TY - JOUR TI - Over-expressing the C3 photosynthesis cycle enzyme Sedoheptulose-1-7 Bisphosphatase improves photosynthetic carbon gain and yield under fully open air CO2fumigation (FACE) AU - Rosenthal, David M AU - Locke, Anna M AU - Khozaei, Mahdi AU - Raines, Christine A AU - Long, Stephen P AU - Ort, Donald R T2 - BMC Plant Biology AB - Abstract Background Biochemical models predict that photosynthesis in C 3 plants is most frequently limited by the slower of two processes, the maximum capacity of the enzyme Rubisco to carboxylate RuBP (V c,max ), or the regeneration of RuBP via electron transport (J). At current atmospheric [CO 2 ] levels Rubisco is not saturated; consequently, elevating [CO 2 ] increases the velocity of carboxylation and inhibits the competing oxygenation reaction which is also catalyzed by Rubisco. In the future, leaf photosynthesis ( A ) should be increasingly limited by RuBP regeneration, as [CO 2 ] is predicted to exceed 550 ppm by 2050. The C 3 cycle enzyme sedoheptulose-1,7 bisphosphatase (SBPase, EC 3.1.3.17) has been shown to exert strong metabolic control over RuBP regeneration at light saturation. Results We tested the hypothesis that tobacco transformed to overexpressing SBPase will exhibit greater stimulation of A than wild type (WT) tobacco when grown under field conditions at elevated [CO 2 ] (585 ppm) under fully open air fumigation. Growth under elevated [CO 2 ] stimulated instantaneous A and the diurnal photosynthetic integral ( A ') more in transformants than WT. There was evidence of photosynthetic acclimation to elevated [CO 2 ] via downregulation of V c,max in both WT and transformants. Nevertheless, greater carbon assimilation and electron transport rates (J and J max ) for transformants led to greater yield increases than WT at elevated [CO 2 ] compared to ambient grown plants. Conclusion These results provide proof of concept that increasing content and activity of a single photosynthesis enzyme can enhance carbon assimilation and yield of C 3 crops grown at [CO 2 ] expected by the middle of the 21st century. DA - 2011/8/31/ PY - 2011/8/31/ DO - 10.1186/1471-2229-11-123 VL - 11 IS - 1 J2 - BMC Plant Biol LA - en OP - SN - 1471-2229 UR - http://dx.doi.org/10.1186/1471-2229-11-123 DB - Crossref ER - TY - JOUR TI - Microbial biomass and soil fauna during the decomposition of cover crops in no-tillage system,Biomassa microbiana e fauna do solo durante a decomposição de plantas de cobertura em sistema plantio direto AU - Gatiboni, L.C. AU - Coimbra, J.L.M. AU - Denardin, R.B.N. AU - Wildner, L.P. T2 - Revista Brasileira de Ciencia do Solo DA - 2011/// PY - 2011/// VL - 35 IS - 4 SP - 1151-1157 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80054981301&partnerID=MN8TOARS ER - TY - JOUR TI - Ammonia volatilization following soil application of conventional urea or urea with urease inhibitor,Volatilização De Amônia do solo após a aplicação de ureia convencional ou com inibidor de urease AU - Tasca, F.A. AU - Ernani, P.R. AU - Rogeri, D.A. AU - Gatiboni, L.C. AU - Cassol, P.C. T2 - Revista Brasileira de Ciencia do Solo AB - Volatilização de NH3 é a principal reação que diminui a eficiência de utilização pelas plantas do N proveniente da ureia, quando ela é aplicada sobre a superfície do solo. A fim de minimizar essa perda, produtos têm sido misturados à ureia para inibir temporariamente a ação da urease. Este trabalho objetivou avaliar alternativas de aplicação de um fertilizante com inibidor de urease, visando a diminuir a volatilização de NH3 relativamente à ureia convencional, em algumas condições ambientais e de solo. Foram desenvolvidos quatro experimentos, todos em condições de laboratório, em 2007 e 2008, em Cambissolo Húmico. Os tratamentos variaram em cada estudo e incluíram combinações de níveis de pH do solo (natural; 5,5; 6,3; e 6,8), umidade do solo (5, 10 ou 20 % de água) e temperaturas ambientais (18 e 35 ºC), além de estados físicos (sólido ou líquido) e de métodos de aplicação dos fertilizantes (na superfície ou incorporado ao solo). As unidades experimentais foram constituídas por bandejas plásticas (23 x 51 x 17 cm) com 12 kg de solo, numa espessura de 15 cm, sobre as quais foram instaladas câmaras coletoras de NH3. A amônia volatilizada foi determinada em várias épocas, nos primeiros 28 dias após a aplicação dos fertilizantes. O pico de volatilização diária de NH3 ocorreu sempre na primeira semana depois da adição dos fertilizantes ao solo, e aconteceu dois a três dias mais tarde para a ureia com inibidor de urease, em relação à ureia convencional. A volatilização de NH3 nem sempre foi maior para a ureia convencional em comparação ao fertilizante contendo inibidor de urease, tampouco para o estado líquido em relação ao granulado. A volatilização de NH3 aumentou com a elevação do pH, da temperatura e da dose aplicada de N e foi menor nos extremos de umidade (solo com 5 % ou com 20 % de água). Para os fertilizantes aplicados sobre a superfície do solo, a taxa máxima de perda diária foi correspondente a 14 kg ha-1 de N, e a perda total acumulada variou de 2 a 50 % do N aplicado, dependendo principalmente do estado físico em que o fertilizante foi aplicado, da umidade do solo e da temperatura ambiente. A incorporação dos fertilizantes amídicos ao solo foi a maneira mais eficaz de minimizar as perdas de N por volatilização. DA - 2011/// PY - 2011/// DO - 10.1590/S0100-06832011000200018 VL - 35 IS - 2 SP - 493-509 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79958785746&partnerID=MN8TOARS ER - TY - JOUR TI - Identification of Plasmodium vivax Proteins with Potential Role in Invasion Using Sequence Redundancy Reduction and Profile Hidden Markov Models T2 - PLoS ONE AB - This study describes a bioinformatics approach designed to identify Plasmodium vivax proteins potentially involved in reticulocyte invasion. Specifically, different protein training sets were built and tuned based on different biological parameters, such as experimental evidence of secretion and/or involvement in invasion-related processes. A profile-based sequence method supported by hidden Markov models (HMMs) was then used to build classifiers to search for biologically-related proteins. The transcriptional profile of the P. vivax intra-erythrocyte developmental cycle was then screened using these classifiers.A bioinformatics methodology for identifying potentially secreted P. vivax proteins was designed using sequence redundancy reduction and probabilistic profiles. This methodology led to identifying a set of 45 proteins that are potentially secreted during the P. vivax intra-erythrocyte development cycle and could be involved in cell invasion. Thirteen of the 45 proteins have already been described as vaccine candidates; there is experimental evidence of protein expression for 7 of the 32 remaining ones, while no previous studies of expression, function or immunology have been carried out for the additional 25.The results support the idea that probabilistic techniques like profile HMMs improve similarity searches. Also, different adjustments such as sequence redundancy reduction using Pisces or Cd-Hit allowed data clustering based on rational reproducible measurements. This kind of approach for selecting proteins with specific functions is highly important for supporting large-scale analyses that could aid in the identification of genes encoding potential new target antigens for vaccine development and drug design. The present study has led to targeting 32 proteins for further testing regarding their ability to induce protective immune responses against P. vivax malaria. DA - 2011/10/3/ PY - 2011/10/3/ DO - 10.1371/journal.pone.0025189 UR - http://dx.doi.org/10.1371/journal.pone.0025189 ER - TY - JOUR TI - NClassG+: A classifier for non-classically secreted Gram-positive bacterial proteins T2 - BMC Bioinformatics AB - Most predictive methods currently available for the identification of protein secretion mechanisms have focused on classically secreted proteins. In fact, only two methods have been reported for predicting non-classically secreted proteins of Gram-positive bacteria. This study describes the implementation of a sequence-based classifier, denoted as NClassG+, for identifying non-classically secreted Gram-positive bacterial proteins.Several feature-based classifiers were trained using different sequence transformation vectors (frequencies, dipeptides, physicochemical factors and PSSM) and Support Vector Machines (SVMs) with Linear, Polynomial and Gaussian kernel functions. Nested k-fold cross-validation (CV) was applied to select the best models, using the inner CV loop to tune the model parameters and the outer CV group to compute the error. The parameters and Kernel functions and the combinations between all possible feature vectors were optimized using grid search.The final model was tested against an independent set not previously seen by the model, obtaining better predictive performance compared to SecretomeP V2.0 and SecretPV2.0 for the identification of non-classically secreted proteins. NClassG+ is freely available on the web at http://www.biolisi.unal.edu.co/web-servers/nclassgpositive/. DA - 2011/1/14/ PY - 2011/1/14/ DO - 10.1186/1471-2105-12-21 UR - http://dx.doi.org/10.1186/1471-2105-12-21 ER - TY - SOUND TI - Turf Selection Innovations AU - Miller, Grady DA - 2011/1/25/ PY - 2011/1/25/ ER - TY - SOUND TI - Weed Control Basics for Sports Turf AU - Miller, Grady DA - 2011/9/20/ PY - 2011/9/20/ ER - TY - CONF TI - The Influence of Athletic Field Paints and Their Application Methods AU - Miller, Grady T2 - North Carolina/South Carolina Parks and Recreation Conference C2 - 2011/9/13/ CY - Charleston, SC DA - 2011/9/13/ PY - 2011/9/13/ ER - TY - SOUND TI - Turf Managers Must Haves AU - Miller, Grady DA - 2011/1/25/ PY - 2011/1/25/ ER - TY - CONF TI - Troubleshooting Athletic Fields in Western NC AU - Miller, Grady T2 - Western Turfgrass Conference C2 - 2011/3/8/ CY - Brevard, NC DA - 2011/3/8/ PY - 2011/3/8/ ER - TY - SOUND TI - Managing Ultradwarf Bermudagrass Golf Greens in NC AU - Miller, Grady DA - 2011/4/5/ PY - 2011/4/5/ ER - TY - SOUND TI - Warm-Season Athletic Field Management Q&A AU - Miller, Grady DA - 2011/1/14/ PY - 2011/1/14/ ER - TY - CONF TI - Managing Lawns during the Worst of Times AU - Miller, Grady T2 - Master-Gardener Conference C2 - 2011/5/11/ CY - Raleigh, NC DA - 2011/5/11/ PY - 2011/5/11/ ER - TY - SOUND TI - Turning Your Fields Green AU - Miller, Grady DA - 2011/1/14/ PY - 2011/1/14/ ER - TY - CONF TI - Zoysiagrass Research at NCSU AU - Miller, Grady T2 - North Carolina Landscape Architect Conference C2 - 2011/5/6/ CY - Durham, NC DA - 2011/5/6/ PY - 2011/5/6/ ER - TY - SOUND TI - Turfgrass Water Requirements AU - Miller, Grady DA - 2011/8/17/ PY - 2011/8/17/ M3 - Workshop ER - TY - SOUND TI - Bentgrass Decline: Influence of Cultural Practices AU - Miller, Grady DA - 2011/12/6/ PY - 2011/12/6/ ER - TY - SOUND TI - Irrigation Management and Smart Irrigation Controllers AU - Miller, Grady DA - 2011/12/6/ PY - 2011/12/6/ ER - TY - SOUND TI - New Discoveries with Athletic Turf Paints AU - Miller, Grady DA - 2011/6/15/ PY - 2011/6/15/ ER - TY - SOUND TI - Selecting Grasses for Lawns AU - Miller, Grady DA - 2011/1/6/ PY - 2011/1/6/ ER - TY - CONF TI - Baseball Fall Fertilization for Overseed and Non-Overseed AU - Miller, Grady T2 - Minor League Baseball Symposium C2 - 2011/9/9/ CY - Durham, NC DA - 2011/9/9/ PY - 2011/9/9/ ER - TY - SOUND TI - Landscape Turf Selection and Management AU - Miller, Grady DA - 2011/1/27/ PY - 2011/1/27/ ER - TY - CONF TI - Smart Irrigation for Turfgrass AU - Miller, Grady T2 - Chatham County Landscape Conference C2 - 2011/2/1/ CY - Silk Hope, NC DA - 2011/2/1/ PY - 2011/2/1/ ER - TY - CONF TI - Irrigation Management and Smart Controllers for P&R Use AU - Miller, Grady T2 - North Carolina/South Carolina Parks and Recreation Conference C2 - 2011/9/13/ CY - Charleston, SC DA - 2011/9/13/ PY - 2011/9/13/ ER - TY - CONF TI - Soil Testing and Fertility Programing AU - Miller, Grady T2 - North Carolina/South Carolina Parks and Recreation Conference C2 - 2011/9/13/ CY - Charleston, SC DA - 2011/9/13/ PY - 2011/9/13/ ER - TY - SOUND TI - NCSU Research at Lake Wheeler Field Lab AU - Miller, Grady DA - 2011/10/6/ PY - 2011/10/6/ ER - TY - SOUND TI - Landscape Fertility Programs AU - Miller, Grady DA - 2011/3/3/ PY - 2011/3/3/ ER - TY - SOUND TI - Granular Fertilizer Programming AU - Miller, Grady DA - 2011/11/15/ PY - 2011/11/15/ ER - TY - SOUND TI - Turf Research Programs at NCSU AU - Miller, Grady DA - 2011/3/3/ PY - 2011/3/3/ ER - TY - CONF TI - Products Necessary for Safe, Attractive, and Playable Athletic Surfaces AU - Miller, Grady T2 - NC and SC Sports Turf Managers Association Meeting C2 - 2011/11/16/ CY - Myrtle Beach, SC DA - 2011/11/16/ PY - 2011/11/16/ ER - TY - SOUND TI - Smart Irrigation AU - Miller, Grady DA - 2011/5/31/ PY - 2011/5/31/ ER - TY - SOUND TI - Irrigation Design Principles AU - Miller, Grady DA - 2011/7/14/ PY - 2011/7/14/ ER - TY - CONF TI - Evaluation of Athletic Field Paints and Turf Colorants and their Impact on Turfgrass Performance AU - Miller, Grady T2 - Turf Center Symposium C2 - 2011/6/23/ CY - Raleigh, NC DA - 2011/6/23/ PY - 2011/6/23/ ER - TY - SOUND TI - Turfgrass Program at NCSU AU - Miller, Grady DA - 2011/7/28/ PY - 2011/7/28/ ER - TY - SOUND TI - Statistical analysis of Specialty Crop Turfgrass Cultivars AU - Miller, Grady DA - 2011/8/9/ PY - 2011/8/9/ ER - TY - CONF TI - Sports Turf Management AU - Miller, Grady T2 - NC Sports Turf Managers Western NC Spring Meeting C2 - 2011/4/28/ CY - Morganton, NC DA - 2011/4/28/ PY - 2011/4/28/ ER - TY - SOUND TI - Sports Turf Research at NCSU AU - Miller, Grady DA - 2011/7/26/ PY - 2011/7/26/ ER - TY - SOUND TI - Establishment of Turfgrasses AU - Miller, Grady DA - 2011/2/17/ PY - 2011/2/17/ ER - TY - JOUR TI - Organic matter accumulation in creeping bentgrass greens AU - Carley, D.S. AU - Goodman, D. AU - Sermons, D.S. AU - Bowman, D. AU - Miller, G. AU - Rufty, T. T2 - Golf Course Manage DA - 2011/// PY - 2011/// VL - 79 IS - 4 SP - 99 ER - TY - JOUR TI - What is important now? AU - Miller, G.L. T2 - SportsTurf DA - 2011/// PY - 2011/// VL - 27 IS - 3 SP - 58 ER - TY - JOUR TI - Turf textbooks 101: What’s currently being taught AU - Bell, G. AU - McQuillen, T. AU - Horvath, B. AU - Stier, J. AU - Rossi, F. AU - Miller, G. AU - McNitt, A. AU - Guertal, B. AU - Scott, B. AU - Goatley, M. AU - Rogers, T. T2 - SportsTurf DA - 2011/// PY - 2011/// VL - 27 IS - 5 SP - 20-23 ER - TY - JOUR TI - Tiger stipe field AU - Miller, G.L. T2 - SportsTurf DA - 2011/// PY - 2011/// VL - 27 IS - 1 SP - 54 ER - TY - JOUR TI - Head games AU - Miller, G.L. T2 - SportsTurf DA - 2011/// PY - 2011/// VL - 27 IS - 7 SP - 54 ER - TY - JOUR TI - Sowing thoughts for fall sports AU - Miller, G.L. T2 - SportsTurf DA - 2011/// PY - 2011/// VL - 27 IS - 9 SP - 46 ER - TY - JOUR TI - First timer AU - Miller, G.L. T2 - SportsTurf DA - 2011/// PY - 2011/// VL - 27 IS - 11 SP - 50 ER - TY - JOUR TI - University turfgrass research update: North Carolina State University AU - Miller, G.L. AU - Reynolds, C. AU - Pinnix, D. AU - Brinton, S. T2 - SportsTurf DA - 2011/// PY - 2011/// VL - 27 IS - 12 SP - 8 ER - TY - JOUR TI - Turning fields green using turf colorants AU - Miller, G.L. T2 - SportsTurf DA - 2011/// PY - 2011/// VL - 27 IS - 1 SP - 16, 18–19 ER - TY - JOUR TI - Maximizing the durability of athletic fields AU - Miller, G.L. T2 - SportsTurf DA - 2011/// PY - 2011/// VL - 27 IS - 1 SP - 22-25 ER - TY - JOUR TI - The effect of calcium on early fiber elongation in cotton ovule culture AU - Taliercio, E. AU - Haigler, C.H. T2 - Journal of Cotton Science DA - 2011/// PY - 2011/// VL - 15 SP - 154–161 SN - 1524-3303 UR - http://journal.cotton.org/journal/2011-15/2/154.cfm ER - TY - CONF TI - Using Colorants on Lawns and Athletic Fields AU - Miller, Grady T2 - Western Turfgrass Conference C2 - 2011/3/8/ CY - Brevard, NC DA - 2011/3/8/ PY - 2011/3/8/ ER - TY - CONF TI - Athletic Field Management AU - Miller, Grady T2 - Missouri Turfgrass Conference C2 - 2011/12/6/ CY - St Louis, MO DA - 2011/12/6/ PY - 2011/12/6/ ER - TY - SOUND TI - NTEP Cultivar Evaluations AU - Miller, Grady DA - 2011/8/10/ PY - 2011/8/10/ ER - TY - SOUND TI - Use of Legacy and Cutless on Zoysiagrass Putting Greens AU - Miller, Grady DA - 2011/8/10/ PY - 2011/8/10/ ER - TY - MGZN TI - High-performance grasses in NC State’s cultivar-evaluation program AU - Miller, G.L. T2 - North Carolina Turfgrass DA - 2011/5// PY - 2011/5// SP - 12,14–17 ER - TY - MGZN TI - Maximizing the durability of athletic fields AU - Miller, G.L. T2 - North Carolina Turfgrass DA - 2011/9// PY - 2011/9// SP - 8–13 ER - TY - MGZN TI - Winterkill: Understanding, preventing, and diagnosing it AU - McCarty, B. AU - Miller, G.L. T2 - North Carolina Turfgrass DA - 2011/11// PY - 2011/11// SP - 10–15 ER - TY - RPRT TI - Soil Management Can Maximize Water Availability AU - Meijer, A. AU - Heitman, J.L. AU - White, J.G. A3 - North Carolina Cooperative Extension DA - 2011/// PY - 2011/// M1 - AG 439 77 M3 - North Carolina State Extension Publications PB - North Carolina Cooperative Extension SN - AG 439 77 ER - TY - RPRT TI - Improved Statewide Soil Moisture Estimation for Hydrologic Assessment and Forecasting AU - Heitman, J.L. AU - White, J.G. AU - Boyles, R. AU - Austin, R. A3 - NC Water Resources Research Institute DA - 2011/// PY - 2011/// M1 - 70251 M3 - WRRI Project Report PB - NC Water Resources Research Institute SN - 70251 ER - TY - JOUR TI - QTL controlling masculinization of ear tips in a maize (Zea mays L.) intraspecific cross AU - Holland, J.B. AU - Coles, N.D. T2 - G3: Genes, Genomes, Genetics AB - Abstract Maize is unique among cereal grasses because of its monoecious flowering habit. Male flowers are normally restricted to the tassel that terminates the primary shoot, whereas female flowers occur as ears at the terminal nodes of lateral branches. We observed Ki14, a tropical maize inbred that produces an ear tipped by a staminate (male) spike under certain environmental conditions, such as long daylengths. Recombinant inbred lines derived from the cross between temperate line B97, which was never observed to produce a staminate ear tip, and Ki14 segregated for the trait under long daylengths. Some progeny lines that had even longer staminate tips than Ki14 were male fertile. We mapped three QTL controlling staminate ear tip using a two-part (binomial plus normal) model. A major QTL on chromosome 3 had a large effect on penetrance of the trait (whether a line would produce staminate ear tips or not) as well as its severity (the length of the staminate tip). This QTL seems to be linked to, but at a distinct position from, a previously mapped QTL controlling the proportion of staminate florets in ears in progeny from crosses between maize and teosinte. Two additional QTL affecting staminate ear tip severity overlapped with QTL controlling photoperiod response previously mapped in this population. Alleles conferring photoperiod sensitivity for delayed flowering at these QTL seem to enhance the production of staminate ear tips under long daylengths. DA - 2011/// PY - 2011/// DO - 10.1534/g3.111.000786 VL - 1 IS - 5 SP - 337-341 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84883041575&partnerID=MN8TOARS KW - maize recombinant inbred lines KW - floral sex determination KW - quantitative trait loci ER - TY - JOUR TI - Mapping QTL controlling southern leaf blight resistance by joint analysis of three related recombinant inbred line populations AU - Negeri, A.T. AU - Coles, N.D. AU - Holland, J.B. AU - Balint-Kurti, P.J. T2 - Crop Science AB - ABSTRACT Southern leaf blight (SLB) is a foliar necrotrophic disease of maize ( Zea mays L.) caused by the ascomycete fungus Cochliobolus heterostrophus (Drechs.) Drechs. It is particularly important in warm humid parts of the world where maize is cultivated, such as the southern Atlantic coast area of the United States and parts of India, Africa, and Western Europe. Quantitative trait loci (QTL) for resistance to SLB disease caused by C. heterostrophus race O were identified in three maize recombinant inbred populations assessed in two environments: Clayton, NC, in the summer and Homestead, FL, in the winter. The three populations were derived from the crosses B73 × CML254, CML254 × B97, and B97 × Ki14. Each of these populations was derived from a cross between a temperate maize line (B73 or B97) and a tropical maize line (Ki14 or CML254). Quantitative trait loci were identified by separate analysis of each population and by joint connected and disconnected analyses of all the populations. The most significant QTL identified were on chromosomes 3, 8, 9,and 10. Joint analysis led to more precise position estimates than separate analysis in each case. Results are discussed in the context of previous SLB QTL analysis studies and a recent flowering time QTL study that used the same populations. The chromosome 8 and 9 QTL colocalized with previously identified flowering time QTL which suggested that the perceived effect on SLB resistance at these QTL may have been mediated through an effect on flowering time DA - 2011/// PY - 2011/// DO - 10.2135/cropsci2010.12.0672 VL - 51 IS - 4 SP - 1571-1579 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79959615426&partnerID=MN8TOARS ER - TY - JOUR TI - Genomic localization of the maize cross-incompatibility gene, Gametophyte factor 1 (ga1) AU - Bloom, J.C. AU - Holland, J.B. T2 - Maydica DA - 2011/// PY - 2011/// VL - 56 IS - 4 SP - 379-387 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84857675839&partnerID=MN8TOARS ER - TY - JOUR TI - Effect of Soil Saturation on Development and 15N-Nitrate Uptake Efficiency of two warm season efficiency of two warm season grasses emerging from dormancy AU - Wherley, Benjamin AU - Bowman, Daniel AU - Shi, Wei AU - Rufty, Thomas, Jr. T2 - Journal of Plant Nutrition AB - Use of effluent on turfgrass is increasing due to population growth and limited water supplies. Because effluent is generated continuously, turf managers may be forced to over-irrigate, leading to soil saturation. Although the nutrients in effluent are readily absorbed by turf, the effects of prolonged soil saturation on uptake are unknown. This research examined the impact of soil saturation on plant development and nitrate uptake of two warm-season turfgrasses emerging from dormancy. Dormant grass/soil cores of hybrid bermudagrass and common centipedegrass were treated to stimulate regrowth, with soil moisture controlled at saturation (∼0.36 cm3 cm−3) or field capacity (0.13 cm3 cm−3). Soil saturation reduced canopy development in both species, but shoot biomass was affected only in bermudagrass. Nitrate uptake by both species was generally unaffected by soil saturation. While extended periods of soil saturation may alter plant development, they do not impair the ability of these turfgrasses to absorb nitrogen. DA - 2011/10// PY - 2011/10// DO - 10.1080/01904167.2011.610489 VL - 34 IS - 13 SP - 2039–2054 SN - 0190-4167 1532-4087 UR - http://dx.doi.org/10.1080/01904167.2011.610489 KW - bermudagrass KW - centipedegrass KW - soil saturation ER - TY - CHAP TI - Coupled Heat and Water Transfer in Soil AU - Heitman, Joshua L. AU - Horton, Robert T2 - Encyclopedia of Agrophysics PY - 2011/// DO - 10.1007/978-90-481-3585-1_33 SP - 155-162 OP - PB - Springer Netherlands SN - 9789048135844 9789048135851 UR - http://dx.doi.org/10.1007/978-90-481-3585-1_33 DB - Crossref ER - TY - CONF TI - Residential Irrigation and Water Conservation Potential of Smart Irrigation Technologies in the Catawba River Basin AU - Vick, Jr., R. L. AU - Grabow, G. L. AU - Huffman, R. L. AU - Miller, G. L. T2 - World Environmental and Water Resources Congress 2011 AB - A three year residential lake water use study in the Catawba River Basin was initiated in 2009 to assess current water withdrawals for landscape irrigation and the water conservation potential of "smart irrigation" technologies. The study is being conducted by North Carolina State University, on properties bordering Duke Energy managed lakes, in North Carolina and South Carolina, that withdraw lake water for landscape irrigation. Assessment of current irrigation water use began in 2009 with a survey to which over 1,400 residences responded (reflecting a 7.4% return rate). Survey results were used to select thirty-six residences (twelve on each of three lakes along the Catawba River) for further evaluation. Water meters with loggers were installed on the main lines of irrigation systems of the selected residences in the summer of 2009 to monitor lake water withdrawals for landscape irrigation under current practices. Two weather stations and four atmometers were also installed in the region to monitor reference evapotransporation during the study. Three types of smart irrigation technologies (two ET-based controllers and one soil-moisture sensor system) were installed at twenty-seven of the study sites at the beginning of the 2010 irrigation season. The technologies were distributed such that each lake had six sites with ET-based controllers, three sites with soil-moisture sensors, and three sites with no intervention, which would serve as a comparison group. Metering of irrigation water withdrawals continued throughout the 2010 irrigation season after installation of smart irrigation technologies. Turf quality assessments were made throughout the year using a visual turf quality rating and a Normalized Difference Vegetative Index (NDVI) obtained with a turf color meter. The study will conclude with data collected in the 2011 irrigation season. C2 - 2011/5/19/ C3 - World Environmental and Water Resources Congress 2011 DA - 2011/5/19/ DO - 10.1061/41173(414)282 PB - American Society of Civil Engineers SN - 9780784411735 UR - http://dx.doi.org/10.1061/41173(414)282 DB - Crossref ER - TY - JOUR TI - Response of Soil Water Chemistry to Simulated Changes in Acid Deposition in the Great Smoky Mountains AU - Cai, Meijun AU - Johnson, Amy M. AU - Schwartz, John S. AU - Moore, Stephen E. AU - Kulp, Matt A. T2 - Journal of Environmental Engineering AB - Watershed recovery from acidic deposition, such as the Noland Divide Watershed in the Great Smoky Mountains National Park, is difficult to predict because of complex biogeochemical processes exhibited in soils. Laboratory soil columns and in situ pan lysimeters were used to investigate soil solution response to simulated reductions in acid deposition. Controlling for influent SO42-, NO3-, and NH4+ concentrations in the column experiments, effluent pH declined similarly to 4.4 among five experimental scenarios from an initial pH of approximately 4.7 and 6.1. Influent-effluent chemical comparisons suggest nitrification and/or SO42- desorption controls effluent pH. Sulfate adsorption occurred when SO42- influent was greater than 25 μmol L-1 and desorption occurred below 15 μmol L-1, which would equate to approximately a 61% reduction in current SO42- deposition levels. Base cation depletion occurred in column experiments, in which 64–60 μmol L-1Ca2+ and 24–27 μmol L-1Mg2+ reductions were measured. Cation depletion rates were pH dependent, primarily caused by soil cation exchange and not weathering. In these soils with base saturation below 7%, complete Ca2+ and Mg2+ depletion was estimated as 90 to 140 years. Protons released by SO42- desorption via ligand exchange are expected to cause further base cation depletion, thereby delaying watershed recovery. Field experiments found SO42- sorption dynamics to be limited by kinetics and hydrologic interflow rates, illustrating how precipitation intensity can influence ion transport from soil to stream. Results from this study provide important information for predicting watershed recovery in the future and suggest needs for further research. DA - 2011/7// PY - 2011/7// DO - 10.1061/(ASCE)EE.1943-7870.0000354 VL - 137 IS - 7 SP - 617-628 J2 - J. Environ. Eng. LA - en OP - SN - 0733-9372 1943-7870 UR - http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0000354 DB - Crossref KW - Acid rain KW - Acids KW - Cations KW - Chemical properties KW - Flow rate KW - Leaching KW - Soil analysis KW - Soil water ER - TY - JOUR TI - Surface Functionality and Carbon Structures in Lignocellulosic-Derived Biochars Produced by Fast Pyrolysis AU - Kim, Pyoungchung AU - Johnson, Amy AU - Edmunds, Charles W. AU - Radosevich, Mark AU - Vogt, Frank AU - Rials, Timothy G. AU - Labbé, Nicole T2 - Energy & Fuels AB - Switchgrass- and pine wood-derived biochars produced by fast pyrolysis were characterized to estimate the degree of thermochemical transformation and to assess their potential use as a soil amendment and to sequester carbon. The feedstocks were pyrolyzed to biochars in an auger reactor at 450, 600, and 800 °C with a residence time of 30 s. Ash contents of switchgrass and pine wood biochars varied from 13 to 22% and from 1.3 to 5.2%, respectively. Nutrients, such as N, P, K, S, Mg, and Ca, in switchgrass biochars ranged from 0.16 to 1.77%. Under combustion conditions, switchgrass chars were decomposed at lower temperatures than pine wood biochars because of the structural differences between the two feedstocks. Principal component analysis of the Fourier transform infrared (FTIR) spectra allowed for the discrimination of all biochars by significant contributions of cellulose-derived functionality at low pyrolysis temperatures, while the same analysis of the Raman spectra presented apparent separation of all biochars by two broad bands at 1587 and 1350 cm–1. These two broad peaks were deconvoluted into pseudo-subpeaks, which revealed that the number of aromatic rings linearly increased with the pyrolysis temperature. Cross-linkages between aromatic rings were also found to increase with thermal treatment, and switchgrass biochars contained a higher number of aromatic rings and cross-linkages than pine wood biochars, which was consistent with turbostratic carbon crystallites in the X-ray diffraction (XRD) pattern. DA - 2011/10/20/ PY - 2011/10/20/ DO - 10.1021/ef200915s VL - 25 IS - 10 SP - 4693-4703 J2 - Energy Fuels LA - en OP - SN - 0887-0624 1520-5029 UR - http://dx.doi.org/10.1021/ef200915s DB - Crossref ER - TY - JOUR TI - Soil Acid-Base Chemistry of a High-Elevation Forest Watershed in the Great Smoky Mountains National Park: Influence of Acidic Deposition AU - Cai, Meijun AU - Johnson, Amy M. AU - Schwartz, John S. AU - Moore, Steve E. AU - Kulp, Matt A. T2 - Water, Air, & Soil Pollution DA - 2011/6/22/ PY - 2011/6/22/ DO - 10.1007/S11270-011-0858-X VL - 223 IS - 1 SP - 289-303 J2 - Water Air Soil Pollut LA - en OP - SN - 0049-6979 1573-2932 UR - http://dx.doi.org/10.1007/S11270-011-0858-X DB - Crossref KW - Soil characteristics KW - Acidic deposition KW - Sulfate adsorption KW - Nitrification KW - Biogeochemical processes KW - Southern Appalachian ER - TY - SOUND TI - Histological analysis of pre- and post-freezing nodal structure of St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze) AU - Claure, T.E. AU - Livingston, D.P. AU - Tuong, T.D. AU - Milla-Lewis, S.R. DA - 2011/10/16/ PY - 2011/10/16/ ER - TY - CONF TI - Recovery of selected Palmer amaranth (Amaranthus palmeri) biotypes from drought stress AU - Chandi, A. AU - Jordan, D.L. AU - York, A.C. AU - Burton, J.D. AU - Milla-Lewis, S.R. AU - Spears, J.F. AU - Whitaker, J. C2 - 2011/// C3 - Proc. South. Weed Sci. Soc. DA - 2011/// VL - 64 SP - 234 ER - TY - SOUND TI - Use of molecular markers for identity preservation in St. Augustinegrass: elucidating the authenticity of ‘Raleigh’ samples from sod farms across the Southeastern United States AU - Kimball, J.A. AU - Zuleta, M.C. AU - Martin, M. AU - Kenworthy, K.E. AU - Chandra, A. AU - Milla-Lewis, S.R. DA - 2011/10/16/ PY - 2011/10/16/ ER - TY - CONF TI - Use of AFLP markers to assess genetic diversity in Palmer Amaranth (Amaranthus palmeri (S. Wats.)) populations from North Carolina and Georgia AU - Chandi, A. AU - Milla-Lewis, S.R. AU - Zuleta, M.C. AU - Jordan, D.L. AU - Burton, J.D. AU - York, A.C. AU - Culpepper, S. C2 - 2011/// C3 - Abstracts of the Weed Science Society of America DA - 2011/// ER - TY - SOUND TI - Turfgrass breeding at NCSU: the first two years AU - Milla-Lewis, S.R. DA - 2011/1/28/ PY - 2011/1/28/ M3 - invited presentation ER - TY - SOUND TI - Characterization of warm-Season turfgrass germplasm using transferred cereal SSR markers AU - Kimball, J.A. AU - Zuleta, M.C. AU - Milla-Lewis, S.R. DA - 2011/10/16/ PY - 2011/10/16/ ER - TY - CONF TI - Genetic analysis of a St. Augustinegrass germplasm collection based on AFLP markers AU - Mulkey, S.E. AU - Zuleta, M.C. AU - Kenworthy, K.E. AU - Lu, H. AU - Milla-Lewis, S.R. C2 - 2011/10/16/ C3 - Proceedings of the American Agronomy International Annual Meeting DA - 2011/10/16/ ER - TY - CONF TI - Evaluation of St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze) germplasm for gray leaf spot resistance AU - Milla-Lewis, S.R. AU - Ma, B. AU - Arellano, C. AU - Zuleta, M.C. AU - Reynolds, W.C. AU - Tredway, L.P. C2 - 2011/10/16/ C3 - Proceedings of the American Agronomy International Annual Meeting DA - 2011/10/16/ ER - TY - JOUR TI - Elucidating the inheritance of evolved resistance to glyphosate in populations of Palmer Amaranth (Amaranthus palmeri (S. Wats.)) from North Carolina AU - Chandi, A. AU - Milla-Lewis, S.R. AU - Zuleta, M.C. AU - Jordan, D.L. AU - Burton, J.D. AU - York, A.C. AU - Culpepper, S. T2 - Weed Society of America DA - 2011/// PY - 2011/// SP - 95 ER - TY - SOUND TI - Development and characterization of simple sequence repeat (SSR) markers for St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze) AU - Mulkey, S.E. AU - Zuleta, M.C. AU - Kenworthy, K.E. AU - Lu, H. AU - Milla-Lewis, S.R. DA - 2011/10/16/ PY - 2011/10/16/ ER - TY - JOUR TI - Spatial and isotopic analysis of watershed soil loss and reservoir sediment accumulation rates in Lake Anna, Virginia, USA AU - Odhiambo, Ben K. AU - Ricker, Matthew C. T2 - Environmental Earth Sciences DA - 2011/5/15/ PY - 2011/5/15/ DO - 10.1007/s12665-011-1098-5 VL - 65 IS - 1 SP - 373-384 J2 - Environ Earth Sci LA - en OP - SN - 1866-6280 1866-6299 UR - http://dx.doi.org/10.1007/s12665-011-1098-5 DB - Crossref KW - Soil erosion KW - Reservoir sedimentation KW - Land use KW - (210)Pb KW - RUSLE2 ER - TY - JOUR TI - Utilizing cover crop mulches to reduce tillage in organic systems in the southeastern USA AU - Reberg-Horton, S. Chris AU - Grossman, Julie M. AU - Kornecki, Ted S. AU - Meijer, Alan D. AU - Price, Andrew J. AU - Place, George T. AU - Webster, Theodore M. T2 - Renewable Agriculture and Food Systems AB - Abstract Organic systems in the southeastern USA offer unique challenges and solutions to crop production due to regional soil and climate characterized by highly weathered soil types, high precipitation and the capacity to grow cover crops in the winter. Recently, the interest of producers and researchers in high-residue cover crops and conservation tillage systems has increased. Various designs of the roller–crimper to manage cover crops have been invented and demonstrated to growers in the southeastern region of the USA over the past 17 years. The impacts of high-residue cover crop mulches on the agronomic systems in the region are diverse. Legume cover crops assist with meeting N demand from cash crops though they decompose rapidly and are seldom sufficient for N demanding crops such as corn. Cereal cover crop mulches can have the opposite effect by immobilizing N and have a longer impact on soil moisture and weed dynamics. While undesirable for many crops, N immobilization is one possible mechanism for weed suppression in legume cash crops planted into cereal residues. Other cover crop weed suppression mechanisms include physical impedance, light availability, allelopathy and microclimate effects. Regardless of the cause, successful weed control by mulches is highly dependent on having substantial biomass. The southeastern region is capable of producing cover crop biomass in excess of 9000 kg ha −1 , which is sufficient for weed control in many cash crops, although supplementary weed control is sometimes necessary. Long-term data are needed to predict when farmers should add supplementary weed control. More work is also needed on how much additional N is required for the cash crops and how best to deliver that N in a high-residue environment using organic sources. DA - 2011/// PY - 2011/// DO - 10.1017/s1742170511000469 VL - 27 IS - 01 SP - 41-48 KW - roller-crimper KW - organic KW - no-till ER - TY - JOUR TI - Estimation of heritability of benzoxazinoid production in rye (Secale cereale) using gas chromatographic analysis AU - Brooks, Ashley M. AU - Danehower, David A. AU - Murphy, J. Paul AU - Reberg-Horton, S. Chris AU - Burton, James D. T2 - Plant Breeding AB - With 4 tables Abstract The 2,4‐dihydroxy‐1,4‐benzoxazin‐3‐one (DIBOA) content of Secale cereale is strongly associated with allelopathy. This has led to interest in developing allelopathic cultivars with increased DIBOA to improve weed control in this important cover crop. Objectives of this study were to determine heritability estimates for DIBOA in rye and determine the utility of gas chromatography (GC) as a screening tool in a rye allelopathy breeding programme. A synthetic population of half‐sib families varying in production of DIBOA was analysed. DIBOA concentrations ranged from 0.52 to 1.15 mg/g dwt tissue (mean = 0.70 mg/g dwt). Analysis of variance indicated significant variability for DIBOA content in rye harvested at the flag leaf stage. Year × location × genotype and block (year × location) interactions were also significant. Several genotypes were consistently ‘high’ or ‘low’ DIBOA producers across all locations and years. Narrow sense heritability estimates were 0.18 ± 0.04 SE on a per plot basis and 0.57 ± 0.07 SE on an entry mean basis. GC analysis was determined to be a good system for moderate throughput screening of lines. DA - 2011/9/6/ PY - 2011/9/6/ DO - 10.1111/j.1439-0523.2011.01885.x VL - 131 IS - 1 SP - 104-109 KW - Secale cereale KW - allelopathy KW - DIBOA KW - benzoxazinoid KW - heritability ER - TY - NEWS TI - Canola and spelt T2 - Organic Grain Project Newsletter PY - 2011/// UR - http://www.organicgrains.ncsu.edu/Newsletters/December2011.htm ER - TY - NEWS TI - Canola Seeding Rate Trial Update T2 - Organic Grain Project Newsletter PY - 2011/9// UR - http://www.organicgrains.ncsu.edu/Newsletters/September2011.htm ER - TY - NEWS TI - Year 1 Results of Organic Official Variety Trials: Corn and Soybeans T2 - Organic Grain Project Newsletter PY - 2011/// UR - http://www.organicgrains.ncsu.edu/Newsletters/December2011.htm ER - TY - NEWS TI - Organic Wheat OVT Results T2 - Organic Grain Project Newsletter PY - 2011/9// UR - http://www.organicgrains.ncsu.edu/Newsletters/September2011.htm ER - TY - JOUR TI - Screening tactics for identifying competitive soybean genotypes AU - Place, G.T. AU - Reberg-Horton, S.C. AU - Carter, T.E. T2 - Communications in Soil Science and Plant Analysis DA - 2011/// PY - 2011/// VL - 42 SP - 2654–2665 ER - TY - JOUR TI - Weed management practices determine plant and arthropod diversity and seed predation in vineyards AU - Sanguankeo, P.P. AU - Leon, R.G. T2 - Weed Research AB - S anguankeo PP & L eón RG (2011). Weed management practices determine plant and arthropod diversity and seed predation in vineyards. Weed Research 51 , 404–412. Summary In the Central Coast of California, USA, wine grape growers are making efforts to identify weed control practices that preserve biodiversity in their vineyards while maintaining yields. A field study was conducted in Paso Robles, California in 2006 and 2007 evaluating the effect on plant and ground dwelling arthropod communities of five weed control practices conducted under the vines within the row (berm): (i) flumioxazin, (ii) simazine, (iii) cultivation, (iv) cover crop and (v) untreated control. The cover crop, cultivation and untreated control had 4–50 times higher plant density and more than 15 times higher plant diversity compared with the herbicide treatments. The arthropod activity‐density differed among treatments only in 2007, being higher in the cover crop and untreated control. There was a positive relationship between plant and arthropod diversity ( r 2 = 0.42, P = 0.02 in 2006; r 2 = 0.64, P < 0.001 in 2007). Laboratory seed predation tests of the two most frequently captured carabid beetles, Calathus ruficollis and Tanystoma maculicolle , indicated they predated more of the common weed species Brassica nigra and Capsella bursa‐pastoris , than other weed species tested. Under field conditions, treatments with higher plant diversity and density favoured arthropod seed predation of these weeds. Predation rates were 20–40% in the cover crop and untreated control, double that observed in the herbicide treatments. The cultivation treatment balanced the benefits of promoting diversity while minimising yield reductions caused by weed competition. The results indicate that weed management practices that promote higher plant diversity and density have the potential to yield ecological benefits within vineyards, for example, enhancing the activity of beneficial organisms. DA - 2011/// PY - 2011/// DO - 10.1111/j.1365-3180.2011.00853.x VL - 51 IS - 4 SP - 404–412 KW - herbicides KW - cover crop KW - cultivation KW - Vitis vinifera KW - grapevines KW - biodiversity KW - weed control ER - TY - JOUR TI - Efecto de tres especies de cobertura viva en el control de malezas en una plantacion de banano organico (Musa AAA cv Williams) AU - Ramos, O. AU - Vaquero, R. AU - Leon, R. AU - Ayuso, F. T2 - Tierra Tropical DA - 2011/// PY - 2011/// VL - 7 SP - 1–10 ER - TY - JOUR TI - Incorporation of municipal biosolids affects organic N mineralization and elephantgrass biomass production AU - Castillo, M.S AU - Sollenberger, L.E. AU - Vendramini, J.M.B. AU - Woodard, K.R. AU - O’Connor, G.A. AU - Silveira, M.L. AU - Sartain, J.B. T2 - Agronomy Journal AB - Municipal biosolids (MBS) represents an alternative source of nutrients for the production of bioenergy crops like elephantgrass ( Pennisetum purpureum Schum.). Two experiments were conducted during 2 yr in Florida to evaluate the effect of soil incorporation vs. surface application of MBS on: (i) elephantgrass dry matter (DM) yield, tissue N and P concentration and removal, and soil C and P (Exp. 1); and (ii) organic N mineralization and DM decomposition rates of MBS measured in the field using a litter bag incubation technique (Exp. 2). In Exp. 1, three treatments supplied 350 kg total N ha −1 yr −1 from surface‐applied municipal biosolids (MBS‐SA), soil‐incorporated municipal biosolids (MBS‐INC), and surface‐applied ammonium nitrate (NH 4 NO 3 ). A fourth treatment provided 700 kg total N ha −1 yr −1 from MBS‐SA (double rate of municipal biosolids, 2x‐MBS). In Exp. 2, MBS was field incubated in litter bags placed on the soil surface or at a 5‐cm soil depth. Elephantgrass DM yield, and N and P removal were greater for MBS‐INC than MBS‐SA. Dry matter yield for MBS‐INC was not different than for NH 4 NO 3 fertilizer (22.5 vs. 24.3 Mg ha −1 ). Removal of N and P increased 39 and 10 kg ha −1 yr −1 , respectively, for MBS‐INC and MBS‐SA. Total organic N mineralized was greater for MBS‐INC (386 g kg −1 ) than MBS‐SA (308 g kg −1 ). Incorporation of MBS increases elephantgrass DM yield and nutrient removal compared to surface application and allows MBS to replace a greater proportion of inorganic N fertilizer. DA - 2011/// PY - 2011/// DO - 10.2134/agronj2010.0497 VL - 103 IS - 3 SP - 899–905 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79957605563&partnerID=MN8TOARS ER - TY - JOUR TI - Runoff water quality and vegetative establishment for ground covers on steep slopes AU - Babcock, D.L. AU - McLaughlin, R.A. T2 - Journal of Soil and Water Conservation DA - 2011/// PY - 2011/// VL - 66 IS - 2 SP - 132-141 ER - TY - JOUR TI - Use of sequence-related amplified polymorphism (SRAP) markers for comparing levels of genetic diversity in centipedegrass (Eremochloa ophiuroides (Munro) Hack.) germplasm AU - Milla-Lewis, Susana R. AU - Kimball, Jennifer A. AU - Zuleta, M. Carolina AU - Harris-Shultz, Karen R. AU - Schwartz, Brian M. AU - Hanna, Wayne W. T2 - Genet Resour Crop Evol DA - 2011/// PY - 2011/// DO - 10.1007/s10722-011-9780-8 VL - 59 IS - 7 SP - 1517-1526 KW - Centipedegrass KW - Eremochloa ophiuroides (Munro) Hack. KW - Genetic diversity KW - Germplasm collection KW - SRAP markers ER - TY - JOUR TI - Soil rhizosphere microbial communities and enzyme activities under organic farming in Alabama AU - Gardner, T. AU - Acosta-Martinez, V. AU - Senwo, Z. AU - Dowd, S.E. T2 - Diversity AB - Evaluation of the soil rhizosphere has been limited by the lack of robust assessments that can explore the vast complex structure and diversity of soil microbial communities. Our objective was to combine fatty acid methyl ester (FAME) and pyrosequencing techniques to evaluate soil microbial community structure and diversity. In addition, we evaluated biogeochemical functionality of the microbial communities via enzymatic activities of nutrient cycling. Samples were taken from a silt loam at 0–10 and 10–20 cm in an organic farm under lettuce (Lactuca sativa), potato (Solanum tuberosum), onion (Allium cepa L), broccoli (Brassica oleracea var. botrytis) and Tall fescue pasture grass (Festuca arundinacea). Several FAMEs (a15:0, i15:0, i15:1, i16:0, a17:0, i17:0, 10Me17:0, cy17:0, 16:1ω5c and 18:1ω9c) varied among the crop rhizospheres. FAME profiles of the soil microbial community under pasture showed a higher fungal:bacterial ratio compared to the soil under lettuce, potato, onion, and broccoli. Soil under potato showed higher sum of fungal FAME indicators compared to broccoli, onion and lettuce. Microbial biomass C and enzyme activities associated with pasture and potato were higher than the other rhizospheres. The lowest soil microbial biomass C and enzyme activities were found under onion. Pyrosequencing revealed significant differences regarding the maximum operational taxonomic units (OTU) at 3% dissimilarity level (roughly corresponding to the bacterial species level) at 0–10 cm (581.7–770.0) compared to 10–20 cm (563.3–727.7) soil depths. The lowest OTUs detected at 0–10 cm were under broccoli (581.7); whereas the lowest OTUs found at 10–20 cm were under potato (563.3). The predominant phyla (85%) in this soil at both depths were Bacteroidetes (i.e., Flavobacteria, Sphingobacteria), and Proteobacteria. Flavobacteriaceae and Xanthomonadaceae were predominant under broccoli. Rhizobiaceae, Hyphomicrobiaceae, and Acidobacteriaceae were more abundant under pasture compared to the cultivated soils under broccoli, potato, onion and lettuce. This study found significant differences in microbial community structure and diversity, and enzyme activities of nutrient cycling in this organic farming system under different rhizospheres, which can have implications in soil health and metabolic functioning, and the yield and nutritional value of each crop. DA - 2011/// PY - 2011/// DO - 10.3390/d3030308 VL - 3 IS - 3 SP - 308-328 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84859391710&partnerID=MN8TOARS ER - TY - JOUR TI - Variations of indicator bacteria in a large urban watershed AU - Ibekwe, A. M. AU - Lesch, S. M. AU - Bold, R. M. AU - Leddy, M. B. AU - Graves, A. K. T2 - Transactions of the ASABE AB - The contamination of water resources by nonpoint-source fecal pollution is a major concern to human health and water quality throughout the world. The Santa Ana River (SAR) in southern California is an impaired stream with historically high fecal coliform counts. This study evaluated the presence of indicator bacteria at 13 sites in the middle Santa Ana River watershed (MSAR). The objectives of this study were to: (1) examine spatial and temporal characteristics of fecal bacteria loading during dry weather (low or baseline) flow, wet weather (storm) flow, and recessional flow (72 h after storm) along two creeks, at two wastewater treatment plant (WWTP) outlets, and at a control site in the MSAR; and (2) determine how the various sampling locations affected indicator bacteria concentrations in the watershed. Total coliform (TC), fecal coliform (FC), E. coli, enterococci, and total bacterial concentrations were characterized at 13 locations in the watershed over a two-year period. Analysis of covariance (ANOCOVA) was used to test each specific set of bacteria counts, site effects, water flow conditions, and the four water quality covariate effects. Our results showed that the control site (S1) and WWTP estimates always showed significantly lower indicator bacteria than the channels influenced by urban runoff and agricultural activities. The water flow effects indicated that the recessional flow transported significantly lower bacterial counts into the watershed than either the dry weather flow or the storm or wet weather flow. In addition, bacterial count estimates changed far more significantly across different sites in comparison to estimates across seasons or time. These results imply that total TC, FC, E. coli, and enterococci bacterial counts in the MSAR watershed were strongly influenced by spatial location effects, with contamination due to local agricultural and/or urban runoff, in contrast to elevated upstream contamination and/or discharge contamination associated with the two WWTPs. Therefore, this study has provided data for evaluation of the Santa Ana River watershed's total maximum daily load (TMDL) management plans that could also be applicable to other large watersheds with different nonpoint-source pollutants. DA - 2011/// PY - 2011/// DO - 10.13031/2013.40653 VL - 54 IS - 6 SP - 2227-2236 ER - TY - JOUR TI - Linking plant ecology and long-term hydrology to improve wetland restoration success AU - Caldwell, P. V. AU - Vepraskas, Michael AU - Gregory, J. D. AU - Skaggs, R. W. AU - Huffman, R. L. T2 - Transactions of the ASABE AB - Although millions of dollars are spent restoring wetlands, failures are common, in part because the planted vegetation cannot survive in the restored hydrology. Wetland restoration would be more successful if the hydrologic requirements of wetland plant communities were known so that the most appropriate plants could be selected for the range of projected hydrology at the site. Here we describe how hydrologic models can be used to characterize the long-term hydrology of wetland plant communities, and we show how these results can be used to define wetland design criteria. In our study, we quantified differences in long-term (40-year) hydrologic characteristics of the pond pine woodland (PPW), nonriverine swamp forest (NRSF), high pocosin (HP), and bay forest (BF) plant communities native to the North Carolina Coastal Plain. We found that the median water level was 8 cm below the land surface in PPW and 9, 2, and 8 cm above the land surface for NRSF, HP, and BF, respectively. When the land surface was inundated, the median duration of inundation was 91 d year-1 for PPW and 317, 243, and 307 d year-1 for NRSF, HP, and BF, respectively. Our models suggested that the PPW received an average of 15% of its water input from groundwater inflow, whereas the other communities we modeled did not appear to receive groundwater inflow. Using these results and soil organic layer thickness, we developed and propose design criteria linking soil, vegetation, and hydrology parameters that should contribute to improved restoration success. DA - 2011/// PY - 2011/// DO - 10.13031/2013.40662 VL - 54 IS - 6 SP - 2129–2137 ER - TY - JOUR TI - Field Evaluation of Bioretention Indicator Bacteria Sequestration in Wilmington, North Carolina AU - Hathaway, J. M. AU - Hunt, W. F. AU - Graves, A. K. AU - Wright, J. D. T2 - JOURNAL OF ENVIRONMENTAL ENGINEERING AB - Although bioretention has been shown to remove or sequester a wide range of pollutants, relatively little study has been performed to evaluate its ability to sequester indicator bacteria. Two adjacent bioretention areas in Wilmington, North Carolina, were studied. The primary difference in the design of the two systems was soil depth. One bioretention cell was constructed with 25 cm of fill soil (Bioretention-S) and one with 60 cm of fill soil (Bioretention-D). The systems performed differently for indicator bacteria on the basis of multiple performance evaluation metrics. Bioretention-D showed concentration reductions of 70% and 89% for E. coli and enterococci, respectively. Effluent concentrations from Bioretention-D compared well to US EPA target values and other studies in literature. Conversely, Bioretention-S showed concentration “reductions” of -119% and -102% for E. coli and enterococci, respectively. Effluent concentrations from Bioretention-S were substantially higher than USEPA target values and other studies in literature. Multiple factors were evaluated to determine the cause of performance differences between the two cells. The 25 cm of fill soil in Bioretention-S exhibited poorer runoff detention, likely because of higher soil water flux and decreased contact time relative to Bioretention-D. These differences seemingly led to diminished indicator bacteria sequestration. The results of this study suggest soil depth and hydraulic loading are important design parameters for bioretention implemented to sequester microbes. DA - 2011/12// PY - 2011/12// DO - 10.1061/(asce)ee.1943-7870.0000444 VL - 137 IS - 12 SP - 1103-1113 SN - 1943-7870 KW - Storm water KW - Bioretention KW - Biofiltration KW - Indicator bacteria KW - E. coli KW - Enterococci ER - TY - JOUR TI - Development and molecular characterization of wheat - Aegilops kotschyi addition and substitution lines with high grain protein, iron, and zinc AU - Rawat, Nidhi AU - Neelam, Kumari AU - Tiwari, Vijay K. AU - Randhawa, Gursharn S. AU - Friebe, Bernd AU - Gill, Bikram S. AU - Dhaliwal, Harcharan S. T2 - GENOME AB - Over two billion people, depending largely on staple foods, suffer from deficiencies in protein and some micronutrients such as iron and zinc. Among various approaches to overcome protein and micronutrient deficiencies, biofortification through a combination of conventional and molecular breeding methods is the most feasible, cheapest, and sustainable approach. An interspecific cross was made between the wheat cultivar ‘Chinese Spring’ and Aegilops kotschyi Boiss. accession 396, which has a threefold higher grain iron and zinc concentrations and about 33% higher protein concentration than wheat cultivars. Recurrent backcrossing and selection for the micronutrient content was performed at each generation. Thirteen derivatives with high grain iron and zinc concentrations and contents, ash and ash micronutrients, and protein were analyzed for alien introgression. Morphological markers, high molecular weight glutenin subunit profiles, anchored wheat microsatellite markers, and GISH showed that addition and substitution of homoeologous groups 1, 2, and 7 chromosomes of Ae. kotschyi possess gene(s) for high grain micronutrients. The addition of 1U/1S had high molecular weight glutenin subunits with higher molecular weight than those of wheat, and the addition of 2S in most of the derivatives also enhanced grain protein content by over 20%. Low grain protein content in a derivative with a 2S-wheat translocation, waxy leaves, and absence of the gdm148 marker strongly suggests that the gene for higher grain protein content on chromosome 2S is orthologous to the grain protein QTL on the short arm of group 2 chromosomes. DA - 2011/11// PY - 2011/11// DO - 10.1139/g11-059 VL - 54 IS - 11 SP - 943-953 SN - 1480-3321 KW - wheat KW - Aegilops kotschyi KW - grain iron KW - grain zinc KW - grain protein KW - microsatellite markers KW - HMW-glutenin subunits KW - genomic in situ hybridization ER - TY - JOUR TI - Variability for Resistance to Phytophthora nicotianae Within a Collection of Nicotiana rustica Accessions AU - Nifong, J. M. AU - Nicholson, J. S. AU - Shew, H. D. AU - Lewis, R. S. T2 - PLANT DISEASE AB - Black shank, caused by Phytophthora nicotianae, is one of the most important diseases affecting tobacco (Nicotiana tabacum) production worldwide. Many current tobacco cultivars possess immunity to race 0 of this pathogen conferred by introgressed dominant genetic factors. Novel alleles conditioning resistance to alternative races are desired. The objective of this research was to evaluate variability for black shank resistance within a collection of N. rustica germplasm using both soilborne disease nurseries and controlled race-specific (race 0 and race 1) inoculations. Nearly all of the 86 accessions studied exhibited very high resistance to race 0, and many displayed levels of race 1 resistance greater than that exhibited by the resistant flue-cured tobacco check, 'K 346'. Materials found to be highly resistant to race 0 and race 1 in growth-chamber experiments also had the best survivability in field disease nurseries. N. rustica accessions TR 6, TR 12, TR 16, TR 21, TR 20, TR 48, TR 54, TR 57, and TR 69 could be sources of novel alleles with large effects on black shank resistance, and could have value for burley and flue-cured tobacco breeding. DA - 2011/11// PY - 2011/11// DO - 10.1094/pdis-11-10-0862 VL - 95 IS - 11 SP - 1443-1447 SN - 1943-7692 ER - TY - JOUR TI - Stocking Strategies as Related to Animal and Pasture Productivity of Endophyte-Free Tall Fescue AU - Burns, J. C. AU - Fisher, D. S. T2 - CROP SCIENCE AB - ABSTRACT Tall fescue ( Festuca arundinacea Schreb.) is a well adapted perennial grass used for pasture across the north–south transition zone in the United States. This 3‐yr trial evaluated three stocking strategies to utilize well‐fertilized spring (April to July) growth of endophyte‐free tall fescue for steer and pasture production. Continuous stocked (CS) was compared with a daily allowance (DA) or lax rotation (LR) (7 to 12 d). Forage mass (in kilograms per hectare) averaged 2673 for CS, 3057 at turn on and 2844 residual for DA, and 2851 at turn on and 2559 residual for the LR. Canopies were similar being mainly leaf (54.9%), followed by dead (32.6%), stem (11.9%), and head (0.5%) fractions. Steer daily gains (0.95 kg), stocking rate (6.7 steers ha −1 ), gain per hectare (585 kg), and effective feed units (3111 kg ha −1 ) were similar among stocking strategies. Canopy in vitro true organic matter disappearance (IVTOD) was similar (747 g kg −1 ) among treatments but differed in crude protein (CP), averaging 186 g kg −1 for CS vs. 198 g kg −1 for rotations. Furthermore, DA was less in CP than LR (189 vs. 207 g kg −1 ) but greater in neutral detergent fiber (NDF) (623 vs. 594 g kg −1 ). Diet selected was similar among treatments in IVTOD (885 g kg −1 ), CP (245 g kg −1 ), and NDF (457 g kg −1 ) as was daily grazing time of 11.5 h when monitored by Vibracorder or 12.3 h when monitored by computer. Well‐fertilized tall fescue pastures free of toxic endophyte can accommodate a range of stocking strategies when efficiently utilized in animal production systems. DA - 2011/11// PY - 2011/11// DO - 10.2135/cropsci2011.01.0022 VL - 51 IS - 6 SP - 2868-2877 SN - 1435-0653 ER - TY - JOUR TI - Resistance to Acetolactate Synthase and Acetyl Co-A Carboxylase Inhibitors in North Carolina Italian Ryegrass (Lolium perenne) AU - Chandi, Aman AU - York, Alan C. AU - Jordan, David L. AU - Beam, Josh B. T2 - WEED TECHNOLOGY AB - Diclofop-resistant Italian ryegrass is widespread in southwestern North Carolina, and growers have resorted to using acetolactate synthase (ALS) inhibitors such as mesosulfuron and pyroxsulam to control this weed in wheat. In the spring of 2007, mesosulfuron failed to control Italian ryegrass in several wheat fields. Seed were collected from six fields in two counties and greenhouse studies were conducted to determine response to mesosulfuron and the acetyl-CoA carboxylase (ACCase) inhibitors diclofop and pinoxaden. All populations were resistant to diclofop and cross-resistant to pinoxaden. Five of the six populations were resistant to diclofop, pinoxaden, and mesosulfuron. An additional study with two biotypes confirmed cross-resistance to the ALS inhibitors imazamox, mesosulfuron, and pyroxsulam. Resistance to mesosulfuron was heritable. DA - 2011/// PY - 2011/// DO - 10.1614/wt-d-11-00050.1 VL - 25 IS - 4 SP - 659-666 SN - 1550-2740 KW - Herbicide-resistant weeds KW - cross-resistance KW - selection pressure KW - wheat ER - TY - JOUR TI - Quantitative Trait Loci Analysis for the Effect of Rht-B1 Dwarfing Gene on Coleoptile Length and Seedling Root Length and Number of Bread Wheat AU - Li, P. AU - Chen, J. AU - Wu, P. AU - Zhang, J. AU - Chu, C. AU - See, D. AU - Brown-Guedira, G. AU - Zemetra, R. AU - Souza, E. T2 - CROP SCIENCE AB - ABSTRACT It has been documented that the dwarfing genes, Rht‐B1b and Rht‐D1b , can reduce wheat ( Triticum aestivum L.) coleoptile length (CL), but their effects on number of roots (RN) and root length (RL) have not been determined. Our objectives were to identify quantitative trait loci (QTL) controlling CL, RN, and RL and to determine if any of the QTL correspond to wheat dwarfing genes. A population consisting of 159 recombinant inbred lines (RILs) was derived from the cross of Rio Blanco ( Rht‐B1b , Rht‐D1a ), a semidwarf cultivar with short CL, and IDO444 ( Rht‐B1a , Rht‐D1a ), a tall germplasm with long CL. The CL, RN, longest root length (LRL), and total root length (TRL) were evaluated at two temperature regimes (18 and 22°C). A major QTL mapped to the Rht‐B1 locus on chromosome 4B explained 64% of the phenotypic variation for CL, 9% for LRL, 26% for TRL, and 14% for plant height. The CL of the semidwarf RILs was significantly less than that of the tall lines while the reverse results were observed for LRL and TRL. Our results indicated that the Rht‐B1 gene had the pleiotropic effect of decreasing CL while increasing LRL and TRL. None of the six QTL for RN were mapped to the regions containing the Rht‐B1 locus although semidwarf RILs had more roots than the tall lines. This study suggested that selection of the Rht‐B1b allele tended to increase root biomass, perhaps ameliorating its negative effect of reduced CL. DA - 2011/11// PY - 2011/11// DO - 10.2135/cropsci2011.03.0116 VL - 51 IS - 6 SP - 2561-2568 SN - 0011-183X ER - TY - JOUR TI - Molecular Analysis of Mutant Alleles for Elevated Palmitate Concentration in Soybean AU - De Vries, Brian D. AU - Fehr, Walter R. AU - Welke, Grace A. AU - Dewey, Ralph E. T2 - CROP SCIENCE AB - ABSTRACT S oybean [ Glycine max (L.) Merr.] oil with increased palmitate concentration may be useful for some food and industrial applications. Chemical mutagenesis was used to develop mutant alleles for elevated palmitate concentration that were designated as fap2 (A21), fap4 (A24), fap5 (A27), fap6 (A25), and fap7 (A30) based on classical genetic analysis. The objective of our study was to determine whether the elevated palmitate phenotypes in any of these lines were associated with mutations in either of the two known 3‐ketoacyl‐ACP synthase II (KAS II) genes of soybean, GmKAS IIA and GmKAS IIB . Deoxyribonucleic acid sequence analysis revealed single nucleotide polymorphisms (SNPs) that differentiated mutant and wild‐type alleles in one of the GmKAS genes in lines A21, A25, A27, and A30 but not in A24. The identified SNPs resulted in nonconservative amino acid substitutions that were predicted to impair enzyme function. The fap2 (A21) allele was associated with two consecutive SNPs within the GmKAS IIA gene, confirming its allelic relationship to fap2 (C1727) that was known to have a mutant SNP within the same gene. The allele designated fap5 (A27) also had a SNP within the GmKAS IIA gene, indicating that its designation should be changed to fap2 (A27). The fap6 (A25) and fap7 (A30) alleles each contained a single SNP at different locations within the GmKAS IIB gene. We propose that the designation of the mutant allele in A25 remain fap6 (A25) and that the allele in A30 be changed from fap7 (A30) to fap6 (A30). DA - 2011/11// PY - 2011/11// DO - 10.2135/cropsci2011.03.0156 VL - 51 IS - 6 SP - 2554-2560 SN - 1435-0653 ER - TY - JOUR TI - Microbiological Evaluation of Water Quality from Urban Watersheds for Domestic Water Supply Improvement AU - Ibekwe, A. Mark AU - Murinda, Shelton E. AU - Graves, Alexandria K. T2 - INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH AB - Agricultural and urban runoffs may be major sources of pollution of water bodies and major sources of bacteria affecting the quality of drinking water. Of the different pathways by which bacterial pathogens can enter drinking water, this one has received little attention to date; that is, because soils are often considered to be near perfect filters for the transport of bacterial pathogens through the subsoil to groundwater. The goals of this study were to determine the distribution, diversity, and antimicrobial resistance of pathogenic Escherichia coli isolates from low flowing river water and sediment with inputs from different sources before water is discharged into ground water and to compare microbial contamination in water and sediment at different sampling sites. Water and sediment samples were collected from 19 locations throughout the watershed for the isolation of pathogenic E. coli. Heterotrophic plate counts and E. coli were also determined after running tertiary treated water through two tanks containing aquifer sand material. Presumptive pathogenic E. coli isolates were obtained and characterized for virulent factors and antimicrobial resistance. None of the isolates was confirmed as Shiga toxin E. coli (STEC), but as others, such as enterotoxigenic E. coli (ETEC). Pulsed field gel electrophoresis (PFGE) was used to show the diversity E. coli populations from different sources throughout the watershed. Seventy six percent of the isolates from urban sources exhibited resistance to more than one antimicrobial agent. A subsequent filtration experiment after water has gone through filtration tanks containing aquifer sand material showed that there was a 1 to 2 log reduction in E. coli in aquifer sand tank. Our data showed multiple strains of E. coli without virulence attributes, but with high distribution of resistant phenotypes. Therefore, the occurrence of E. coli with multiple resistances in the environment is a matter of great concern due to possible transfer of resistant genes from nonpathogenic to pathogenic strains that may result in increased duration and severity of morbidity. DA - 2011/12// PY - 2011/12// DO - 10.3390/ijerph8124460 VL - 8 IS - 12 SP - 4460-4476 SN - 1660-4601 KW - pathogenic Escherichia coli KW - indicator bacteria KW - surface water KW - sediment KW - contamination KW - watershed ER - TY - JOUR TI - Influence of Cover Crops on Weed Management in Strip Tillage Peanut AU - Lassiter, Bridget R. AU - Jordan, David L. AU - Wilkerson, Gail G. AU - Shew, Barbara B. AU - Brandenburg, Rick L. T2 - WEED TECHNOLOGY AB - Experiments were conducted in North Carolina during 2005, 2006, and 2007 to determine peanut and weed response when peanut was planted in strip tillage after desiccation of cereal rye, Italian ryegrass, oats, triticale, wheat, and native vegetation by glyphosate and paraquat before planting with three in-season herbicide programs. Control of common ragweed and yellow nutsedge did not differ among cover crop treatments when compared within a specific herbicide program. Applying dimethenamid or S -metolachlor plus diclosulam PRE followed by imazapic POST was more effective than a chloroacetamide herbicide PRE followed by acifluorfen, bentazon, and paraquat POST. Incidence of spotted wilt in peanut (caused by a Tospovirus ) did not differ when comparing cover crop treatments, regardless of herbicide program. Peanut yield increased in all 3 yr when herbicides were applied POST, compared with clethodim only. Peanut yield was not affected by cover crop treatment. Response to cover crop treatments was comparable, suggesting that growers can select cereal rye, Italian ryegrass, oats, or triticale as an alternative to wheat as a cover crop in peanut systems without experiencing differences associated with in-season weed management. DA - 2011/// PY - 2011/// DO - 10.1614/wt-d-11-00064.1 VL - 25 IS - 4 SP - 568-573 SN - 0890-037X KW - Integrated pest management KW - weed management KW - tomato spotted wilt virus ER - TY - JOUR TI - Identifying Soybean Traits of Interest for Weed Competition AU - Place, George T. AU - Reberg-Horton, S. Chris AU - Dickey, David A. AU - Carter, Thomas E., Jr. T2 - CROP SCIENCE AB - ABSTRACT Organic soybean [ Glycine Max (L.) Merr.] producers rely on a variety of tactics for weed management. The use of soybean cultivars with enhanced ability to compete with weeds may increase weed control. Our objective was to identify genetic traits that may enhance soybean's competitive ability to suppress weeds. Experimental design was a split‐split plot with sets of contrasting soybean genotypes assigned to the main plots, individual genotypes assigned to subplots, and weedy and weed‐free sub‐subplots stripped across blocks for side by side comparison of treatments in weedy and weed‐free conditions. Differences in weed biomass were detected among genotypes in both years at 7 wk after emergence. Narrow‐leaflet small‐seeded natto types were generally poor competitors with weeds. Cultivars released as forage types did not have a consistent advantage over the control. Larger‐seeded tofu genotypes were also variable in weed suppressive ability. However, N04‐8906, the genotype with the greatest 100‐seed weight in this study (24 g), stood out as being among the best for weed suppression, soybean biomass accumulation, ground cover at 3 wk, and early season plant height. Optimum models from multiple regression showed seed size to be the most significant trait measured in overall genotype competitive ability in both years. However, seed size effects on ground cover largely dissipated by 5 wk after emergence. DA - 2011/11// PY - 2011/11// DO - 10.2135/cropsci2010.11.0654 VL - 51 IS - 6 SP - 2642-2654 SN - 1435-0653 ER - TY - JOUR TI - IRRIGATION WATERS AS A SOURCE OF PATHOGENIC MICROORGANISMS IN PRODUCE: A REVIEW AU - Pachepsky, Yakov AU - Shelton, Daniel R. AU - McLain, Jean E. T. AU - Patel, Jitendra AU - Mandrell, Robert E. T2 - ADVANCES IN AGRONOMY, VOL 113 DA - 2011/// PY - 2011/// DO - 10.1016/b978-0-12-386473-4.00007-5 VL - 113 SP - 73-138 SN - 0065-2113 ER - TY - JOUR TI - Genetic Analysis of Populations Derived from Matings of Southern and Northern Soybean Cultivars AU - Feng, L. AU - Burton, J. W. AU - Carter, T. E., Jr. AU - Miranda, L. M. AU - St Martin, S. K. AU - Brownie, C. T2 - CROP SCIENCE AB - ABSTRACT Genetic diversity is one of the important considerations in selecting parents for applied cultivar development in soybean [ Glycine max (L.) Merr.]. Recent studies have shown that southern and northern U.S. soybean cultivars belong to two very distinct gene pools based on pedigree and molecular marker analysis. A study was conducted to evaluate the potential of matings between southern and northern cultivars for applied soybean breeding. Nine populations were derived from matings of two southern soybean cultivars, Johnston and Stonewall, with three ancestral, A.K. (Harrow), Lincoln, and Mandarin, and three improved, Flyer, Sibley, and Zane, northern cultivars. Field trials showed statistically significant differences among and within crosses for mean yield, maturity, height, seed quality, seed weight, protein, oil, and fatty acid composition. There were significant differences in means and genetic variances among populations derived from male (northern) cultivars for mean yield and all other traits recorded. Results suggested that improved northern cultivars would be useful parents for practical breeding programs in the south. Populations derived from Flyer produced the highest mean yields. A significant correlation ( r = –0.82) between coefficient of parentage (CP) value and genetic variance estimate for cross yield may indicate that CP is a useful measurement in predicting genetic variation among matings of inbred soybean cultivars. DA - 2011/11// PY - 2011/11// DO - 10.2135/cropsci2010.12.0718 VL - 51 IS - 6 SP - 2479-2488 SN - 1435-0653 ER - TY - JOUR TI - Flaccidgrass Forage Mass and Canopy Characteristics Related to Steer Digesta Kinetics and Intake AU - Burns, J. C. AU - Fisher, D. S. AU - Pond, K. R. T2 - CROP SCIENCE AB - ABSTRACT ‘Carostan’ flaccidgrass ( Pennisetum flaccidum Griseb.) has potential as a perennial, warm‐season grass for pastures. This 2‐yr study examined digesta kinetics, dry matter intake (DMI), and diet of steers as related to canopy characteristics. Steers ( Bos taurus L.) were continuously and variably stocked at canopy heights of Short (15 to 20 cm), Medium (30 to 40 cm), and Tall (45 to 55 cm) with forage mass (FM) of 1245, 2600, and 3585 kg ha −1 , respectively (linear; p < 0.01). Neither mean retention time nor passage rate of either liquid or digesta phases were altered by FM. Fecal output increased linearly ( p = 0.04) from Short to Tall (0.643 to 0.739 kg 100 −1 kg body weight [BW]) indicating a possible variation in DMI. However, DMI and digestible DMI (based on leaf in vitro dry matter disappearance [IVDMD]) were similar among FM (mean = 1.99 and 1.29 kg 100 −1 kg BW). Leaf composed 24.3% of the three canopies and was not altered by FM. Stem increased linearly ( p = 0.01) from 40.1 to 53.1% with height whereas dead tissue declined linearly ( p = 0.06) from 34.8 to 23.4%. Steers selected diets (1 yr data), regardless of FM, similar in IVDMD (mean = 713 g kg −1 ) and neutral detergent fiber (NDF) (mean = 486 g kg −1 ). In general, steer digesta kinetics were not influenced by FM as animals adjusted grazing behavior to result in similar responses. Flaccidgrass canopies were flexible and no particular optimum FM was detecting for an optimum diet. The influence of FM on pasture productivity (regrowth after defoliation) requires additional study. DA - 2011/11// PY - 2011/11// DO - 10.2135/cropsci2011.05.0284 VL - 51 IS - 6 SP - 2895-2903 SN - 0011-183X ER - TY - JOUR TI - Effects of temperature during soybean seed development on defense-related gene expression and fungal pathogen accumulation AU - Upchurch, Robert G. AU - Ramirez, Martha E. T2 - BIOTECHNOLOGY LETTERS DA - 2011/12// PY - 2011/12// DO - 10.1007/s10529-011-0722-5 VL - 33 IS - 12 SP - 2397-2404 SN - 0141-5492 KW - Defense-related gene expression in seeds KW - Fungal pathogens KW - Glycine max KW - Temperature regimen ER - TY - JOUR TI - Effect of Simulated Aminocyclopyrachlor Drift on Flue-Cured Tobacco AU - Lewis, D. F. AU - Hoyle, S. T. AU - Fisher, L. R. AU - Yelverton, F. H. AU - Richardson, R. J. T2 - WEED TECHNOLOGY AB - Flue-cured tobacco is sensitive to foliar and soil residues of off-target synthetic auxin drift. Aminocyclopyrachlor is a newly developed synthetic auxin herbicide that may be used in right-of-way applications for broadleaf weed and brush control. Aminocyclopyrachlor is considered a reduced-risk alternative in rights-of-way compared with similar compounds because of its low application rate and volatility risk. However, no research is available on the response of field-grown, flue-cured tobacco to aminocyclopyrachlor drift exposure. Research was conducted in 2009 and 2010 at the Border Belt Tobacco Research Station in Whiteville, NC, to determine the response of ‘NC 71’ flue-cured tobacco to five simulated drift rates of aminocyclopyrachlor (0.31, 1.6, 3.1, 15.7, and 31.4 g ae ha −1 ) and one aminopyralid (6.1 g ae ha −1 ) simulated drift rates applied pretransplant incorporated, pretransplant unincorporated, 3 wk after transplant, and 6 wk after transplant. All herbicide rates and application timings caused significant visual tobacco injury, ranging from slight to severe with increasing herbicide drift rates. Tobacco plant heights and fresh weights were reduced at all application timings receiving ≥ 15.7 g ha −1 aminocyclopyrachlor and the comparative aminopyralid rate. DA - 2011/// PY - 2011/// DO - 10.1614/wt-d-11-00037.1 VL - 25 IS - 4 SP - 609-615 SN - 0890-037X KW - Off-target movement KW - synthetic auxin ER - TY - JOUR TI - Distinct Genetic Architectures for Male and Female Inflorescence Traits of Maize AU - Brown, Patrick J. AU - Upadyayula, Narasimham AU - Mahone, Gregory S. AU - Tian, Feng AU - Bradbury, Peter J. AU - Myles, Sean AU - Holland, James B. AU - Flint-Garcia, Sherry AU - McMullen, Michael D. AU - Buckler, Edward S. AU - Rocheford, Torbert R. T2 - PLOS GENETICS AB - We compared the genetic architecture of thirteen maize morphological traits in a large population of recombinant inbred lines. Four traits from the male inflorescence (tassel) and three traits from the female inflorescence (ear) were measured and studied using linkage and genome-wide association analyses and compared to three flowering and three leaf traits previously studied in the same population. Inflorescence loci have larger effects than flowering and leaf loci, and ear effects are larger than tassel effects. Ear trait models also have lower predictive ability than tassel, flowering, or leaf trait models. Pleiotropic loci were identified that control elongation of ear and tassel, consistent with their common developmental origin. For these pleiotropic loci, the ear effects are larger than tassel effects even though the same causal polymorphisms are likely involved. This implies that the observed differences in genetic architecture are not due to distinct features of the underlying polymorphisms. Our results support the hypothesis that genetic architecture is a function of trait stability over evolutionary time, since the traits that changed most during the relatively recent domestication of maize have the largest effects. DA - 2011/11// PY - 2011/11// DO - 10.1371/journal.pgen.1002383 VL - 7 IS - 11 SP - SN - 1553-7404 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-81755187332&partnerID=MN8TOARS ER - TY - JOUR TI - Population structure and marker-trait association analysis of the US peanut (Arachis hypogaea L.) mini-core collection AU - Wang, Ming Li AU - Sukumaran, Sivakumar AU - Barkley, Noelle A. AU - Chen, Zhenbang AU - Chen, Charles Y. AU - Guo, Baozhu AU - Pittman, Roy N. AU - Stalker, H. Thomas AU - Holbrook, C. Corley AU - Pederson, Gary A. AU - Yu, Jianming T2 - THEORETICAL AND APPLIED GENETICS DA - 2011/12// PY - 2011/12// DO - 10.1007/s00122-011-1668-7 VL - 123 IS - 8 SP - 1307-1317 SN - 1432-2242 ER - TY - JOUR TI - Nitrogen and Cutting Height Influence Root Development during Warm-Season Turfgrass Sod Establishment AU - Wherley, B. G. AU - Sinclair, T. R. AU - Dukes, M. D. AU - Schreffler, A. K. T2 - AGRONOMY JOURNAL AB - Effective water conservation in the landscape requires identification of cultural management practices that maximize the genetic rooting potential of establishing turfgrass sod. Nitrogen is critical for successful turfgrass establishment; however, there has recently been debate over whether to restrict N fertilization during summer periods in parts of Florida and the United States. This study was undertaken to examine within four warm‐season turfgrass species, the relative influences of cutting height and N fertility on the (i) rate of root extension and (ii) root biomass produced over a 10‐wk period. ‘Tifway 419’ bermudagrass ( Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy), ‘Empire’ zoysiagrass ( Zoysia japonica Steud.), ‘Argentine’ bahiagrass ( Paspalum notatum Flugge), and ‘Floratam’ St. Augustinegrass ( Stenotaphrum secundatum Walt. Kuntze) were established from 10‐cm diam. by 5‐cm deep plugs of turfgrass sod into 90‐cm tall, clear acrylic tubes. Experimental treatments were arranged in a complete factorial that was repeated over two growing seasons. Rates of root extension were calculated from weekly measures of the deepest visible root in each column. Root extension rates ranged from ∼1.0 to 1.8 cm d −1 during the studies, with bahiagrass exhibiting the most rapid root extension of the four species. The results demonstrated that increasing N fertility during establishment increased rates of root extension into deep soil, particularly in bermudagrass. Height of cut had no effect on rate of root extension for most species, but higher cutting height did promote more rapid root extension in bermudagrass. Although not significantly accelerating vertical root extension in most species, maintaining sod at the higher cutting heights resulted in significantly greater root proliferation within both upper and lower soil depths for all species. The results emphasize the importance of proper N fertility and cutting heights for optimizing root development of different turfgrass species during sod establishment. DA - 2011/// PY - 2011/// DO - 10.2134/agronj2011.0146 VL - 103 IS - 6 SP - 1629-1634 SN - 0002-1962 ER - TY - JOUR TI - Nitrogen Delivery from Legume Cover Crops in No-Till Organic Corn Production AU - Parr, M. AU - Grossman, J. M. AU - Reberg-Horton, S. C. AU - Brinton, C. AU - Crozier, C. T2 - AGRONOMY JOURNAL AB - Sixteen winter annual cover crop cultivars were grown in North Carolina to determine total N accumulation, biological N fixation (BNF) potential, and compatibility with a roller‐crimper‐terminated organic corn ( Zea mays L.) production system. Cover crops and termination dates were tested in a stripped block design. Treatments included hairy vetch ( Vicia villosa Roth), common vetch ( Vicia sativa L.), crimson clover ( Trifolium incarnatum L.), Austrian winter pea ( Pisum sativum L.), berseem clover ( Trifolium alexandrinum L.), subterranean clover ( Trifolium subterraneum L.), narrow leaf lupin ( Lupinus angustifolius L.), and Balansa clover ( Trifolium michelianum Savi.), as well as bicultures of rye ( Secale cereale L.), hairy vetch, and Austrian winter pea. Roller‐crimper termination occurred in mid‐April, early May, and mid‐May. Total biomass, N concentration, and C/N ratios were determined for cover crops at all roll times and natural 15 N abundance at the optimal kill date. Hairy vetch and crimson clover monocultures had the greatest overall biomass in 2009, and bicultures the greatest biomass in 2010. Crimson clover successfully terminated in late April, hairy vetch and Austrian winter pea in mid‐May, and berseem clover and common vetch in late May. All cover crops except lupin and subterranean clover derived between 70 and 100% of their N from the atmosphere. Corn response to cover crop mulches was significantly affected by the time of rolling, with poor stands resulting from competition with insufficiently terminated mulches. Crimson, Balansa, and subterranean clover mulches resulted in poor corn yields despite relatively high levels of total N. The highest corn yields were achieved in hairy vetch and rye plus hairy vetch bicultures. DA - 2011/// PY - 2011/// DO - 10.2134/agronj2011.0007 VL - 103 IS - 6 SP - 1578-1590 SN - 0002-1962 ER - TY - JOUR TI - Characterization of a major QTL for adult plant resistance to stripe rust in US soft red winter wheat AU - Hao, Yuanfeng AU - Chen, Zhenbang AU - Wang, Yingying AU - Bland, Dan AU - Buck, James AU - Brown-Guedira, Gina AU - Johnson, Jerry T2 - THEORETICAL AND APPLIED GENETICS DA - 2011/12// PY - 2011/12// DO - 10.1007/s00122-011-1675-8 VL - 123 IS - 8 SP - 1401-1411 SN - 0040-5752 ER - TY - JOUR TI - Turfgrass Root Response to Subsurface Soil Compaction AU - Matthieu, Donald E. AU - Bowman, Daniel C. AU - Thapa, Bir B. AU - Cassel, D. Keith AU - Rufty, Thomas W. T2 - COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS AB - Soil compaction prevents turfgrass roots from growing deep into the soil and may limit access to water and nutrients. The objective of this study was to characterize the ability of turfgrass roots to penetrate a compacted subsurface layer. Seven turfgrasses were grown in soil columns. Each column was divided into three sections with the top and bottom packed to a bulk density of 1.6 g cm−3, and the middle (treatment) layer packed to 1.6, 1.7, 1.8, 1.9, or 2.0 g cm−3. Subsurface compaction reduced root mass for two of the species, and inhibited deep root growth in all seven species, with the greatest reduction occurring between 1.7 and 1.8 g cm−3. There appears to be little difference between species in ability to penetrate compacted soils, suggesting that soil preparation and routine management practices, rather than grass selection, is the more viable way to handle soil compaction problems in turf. DA - 2011/// PY - 2011/// DO - 10.1080/00103624.2011.622826 VL - 42 IS - 22 SP - 2813-2823 SN - 1532-2416 KW - Compaction KW - rhizosphere KW - soil structure ER - TY - JOUR TI - Screening Tactics for Identifying Competitive Soybean Genotypes AU - Place, G. T. AU - Reberg-Horton, S. C. AU - Carter, T. E. AU - Brinton, S. R. AU - Smith, A. N. T2 - COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS AB - Weed control is the biggest obstacle for farmers transitioning to organic soybean production. The breeding of competitive cultivars may provide organic soybean producers with another weed-management tactic. Soybean breeders need screening protocols to identify competitive genotypes. In 2007 and 2008, we tested two screening tactics to nondestructively estimate canopy coverage during the critical period for weed competition. Overhead photography at 3 and 5 weeks after emergence and light interception measurements at 4 and 6 weeks after emergence were compared in their ability to predict soybean and weed biomass at the end of the critical period for weed competition. Photographic digital image processing techniques were compared. Overhead photography at 5 weeks after emergence was most effective at predicting weed-free soybean biomass but overhead photography at 3 weeks after emergence was best able to predict weed biomass associated with soybean genotypes at the end of the critical period for weed competition. DA - 2011/// PY - 2011/// DO - 10.1080/00103624.2011.614040 VL - 42 IS - 21 SP - 2654-2665 SN - 0010-3624 KW - Crop competitiveness KW - organic crop breeding ER - TY - JOUR TI - Lending technologies, lending specialization, and minority access to small-business loans AU - Mitchell, Karlyn AU - Pearce, Douglas K. T2 - SMALL BUSINESS ECONOMICS DA - 2011/10// PY - 2011/10// DO - 10.1007/s11187-009-9243-1 VL - 37 IS - 3 SP - 277-304 SN - 1573-0913 KW - Small-business loans KW - Lending technologies KW - Lending specialization KW - Relationship lending KW - Fair lending KW - Discrimination KW - Asymmetric information KW - SME finance ER - TY - JOUR TI - Tolerance of three warm-season turfgrasses to increasing and prolonged soil water deficit AU - Cathey, S. E. AU - Kruse, J. K. AU - Sinclair, T. R. AU - Dukes, M. D. T2 - HortScience DA - 2011/// PY - 2011/// VL - 46 IS - 11 SP - 1550-1555 ER - TY - JOUR TI - A simple model for chickpea development, growth and yield AU - Soltani, Afshin AU - Sinclair, Thomas R. T2 - FIELD CROPS RESEARCH AB - Chickpea (Cicer arietinum L.) yield is unstable and low in major producer countries. A robust crop model can assist in evaluation of possible genetic improvements and cultural management practices to improve yield. The objectives of this study were to develop and test a chickpea simulation model that could be used across a wide range of environments. This model simulates phenological development, leaf development and senescence, mass partitioning, plant nitrogen balance, yield formation and soil water balance. Responses of crop processes to environmental factors of solar radiation, photoperiod, temperature, nitrogen and water availability, and genotype differences were included in the model. The model uses a daily time step and readily available weather and soil information. The model was tested using independent data from a wide range of growth and environmental conditions. In most cases, simulated grain yield were similar to observed yield (ranging from 20 to 379 g m−2) with a root mean square root of 26 g m−2 (15% of average measured yield). It was concluded that the model generality, i.e., constant parameters for genotypes across locations, and applicability to a wide range of environmental conditions factors made this model especially useful. DA - 2011/11/14/ PY - 2011/11/14/ DO - 10.1016/j.fcr.2011.06.021 VL - 124 IS - 2 SP - 252-260 SN - 1872-6852 KW - Chickpea KW - Simulation KW - Yield KW - Water KW - Nitrogen ER - TY - JOUR TI - THREE NEW TEOSINTES (ZEA SPP., POACEAE) FROM MEXICO AU - Sanchez G, J. J. AU - Cruz L, L. De AU - Vidal M, V. A. AU - Ron P, J. AU - Taba, S. AU - Santacruz-Ruvalcaba, F. AU - Sood, S. AU - Holland, J. B. AU - Ruiz C, J. A. AU - Carvajal, S. AU - Aragon C, F. AU - Chavez T, V. H. AU - Morales R, M. M. AU - Barba-Gonzalez, R. T2 - AMERICAN JOURNAL OF BOTANY AB - Teosinte species are the closest relatives of maize and represent an important but increasingly rare genetic resource for maize improvement and the study of evolution by domestication. Three morphologically and ecologically distinct teosinte populations were recently discovered in México. The taxonomic status of these rare and endangered populations was investigated by detailed comparisons to previously characterized wild Zea species. •Three new teosinte populations were compared to known teosinte taxa on the basis of morphological, ecogeographic, cytological, and molecular characteristics. Phenetic and phylogenetic analyses were performed using morphological and molecular data, respectively. •The newly discovered populations are distinct from each other and from other Zea species to represent three new entities based on their unique combinations of morphological, ecological, ploidy, and DNA markers. A perennial diploid population from Nayarit is distinguished by early maturing plants, and having male inflorescences with few tassel branches and long spikelets. A perennial tetraploid population from Michoacán is characterized by tall and late maturing plants, and having male inflorescences with many branches. An annual diploid population from Oaxaca is characterized by having male inflorescences with fewer branches and longer spikelets than those found in the sister taxa Z. luxurians and Z. nicaraguensis, plants with high thermal requirements, and very long seed dormancy. •Evidence from multiple independent sources suggests placement of the three new populations of teosinte as distinct entities within section Luxuriantes of the genus Zea. However, more extensive DNA marker or sequence data are required to resolve the taxonomy of this genus. DA - 2011/9// PY - 2011/9// DO - 10.3732/ajb.1100193 VL - 98 IS - 9 SP - 1537-1548 SN - 1537-2197 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84857141107&partnerID=MN8TOARS KW - maize KW - Poaceae KW - teosinte KW - Zea ER - TY - JOUR TI - Registration of 'N7003CN' Maturity-Group-VII Soybean with High Yield and Resistance to Race 2 (HG Type 1.2.5.7-) Soybean Cyst Nematode AU - Carter, T. E., Jr. AU - Koenning, S. R. AU - Burton, J. W. AU - Rzewnicki, P. E. AU - Villagarcia, M. R. AU - Bowman, D. T. AU - Arelli, P. R. T2 - JOURNAL OF PLANT REGISTRATIONS AB - ‘N7003CN’ soybean [ Glycine max (L.) Merr.] (Reg. No. CV‐502, PI 661157) was developed and released by the USDA‐ARS in 2010. It is a high‐yielding, maturity‐group (MG) VII, nontransgenic soybean cultivar adapted to the southeastern USA (30–37° N latitude). N7003CN is the first publicly released MG‐VII soybean that is resistant to race 2 (HG type 1.2.5.7) of the soybean cyst nematode (SCN; Heterodera glycines Ichinohe). Race 2 is the dominant type of SCN in North Carolina. N7003CN is also resistant to races 1 and 14 (HG types 2.3‐ and 1.3.5.6.7, respectively), is moderately resistant to races 4 and 5 (HG types 1.2.3.5.6‐ and 2.5.7‐, respectively), and appears to have partial resistance to race 3 (HG type 5.7). Molecular analysis of N7003CN identified SSR markers associated with SCN resistance genes rhg1 , Rhg4 , and Rhg5 . During 2005–2009 in USDA Uniform Soybean Tests, N7003CN yielded 11 and 2% more than the SCN‐susceptible control cultivars ‘Haskell RR’ and ‘N7002’, respectively (46 environments). During 2005–2009 in the North Carolina State University Official Variety Trials (OVT), the yield of N7003CN was equivalent to that of the SCN‐susceptible control cultivar, ‘NC‐Raleigh’. NC‐Raleigh was the highest‐yielding MG‐VII entry in the OVT. The unusual combination of high yield and SCN race‐2 resistance in group‐VII maturity makes this cultivar potentially desirable for conventional and organic production and as breeding stock for commercial breeding. DA - 2011/9// PY - 2011/9// DO - 10.3198/jpr2010.09.0565crc VL - 5 IS - 3 SP - 309-317 SN - 1940-3496 ER - TY - JOUR TI - Genetic effects on total phenolics, condensed tannins and non-structural carbohydrates in loblolly pine (Pinus taeda L.) needles AU - Aspinwall, Michael J. AU - King, John S. AU - Booker, Fitzgerald L. AU - McKeand, Steven E. T2 - TREE PHYSIOLOGY AB - Carbon allocation to soluble phenolics (total phenolics, proanthocyanidins (PA)) and total non-structural carbohydrates (TNC; starch and soluble sugars) in needles of widely planted, highly productive loblolly pine (Pinus taeda L.) genotypes could impact stand resistance to herbivory, and biogeochemical cycling in the southeastern USA. However, genetic and growth-related effects on loblolly pine needle chemistry are not well characterized. Therefore, we investigated genetic and growth-related effects on foliar concentrations of total phenolics, PA and TNC in two different field studies. The first study contained nine different genotypes representing a range of genetic homogeneity, growing in a 2-year-old plantation on the coastal plain of North Carolina (NC), USA. The second study contained eight clones with different growth potentials planted in a 9-year-old clonal trial replicated at two sites (Georgia (GA) and South Carolina (SC), USA). In the first study (NC), we found no genetic effects on total phenolics, PA and TNC, and there was no relationship between genotype size and foliar biochemistry. In the second study, there were no differences in height growth between sites, but the SC site showed greater diameter (diameter at breast height (DBH)) and volume, most likely due to greater tree mortality (lower stocking) which reduced competition for resources and increased growth of remaining trees. We found a significant site × clone effect for total phenolics with lower productivity clones showing 27–30% higher total phenolic concentrations at the GA site where DBH and volume were lower. In contrast to the predictions of growth–defense theory, clone volume was positively associated with total phenolic concentrations at the higher volume SC site, and PA concentrations at the lower volume GA site. Overall, we found no evidence of a trade-off between genotype size and defense, and genetic potential for improved growth may include increased allocation to some secondary metabolites. These results imply that deployment of more productive loblolly pine genotypes will not reduce stand resistance to herbivory, but increased production of total phenolics and PA associated with higher genotype growth potential could reduce litter decomposition rates and therefore, nutrient availability. DA - 2011/8// PY - 2011/8// DO - 10.1093/treephys/tpr073 VL - 31 IS - 8 SP - 831-842 SN - 1758-4469 KW - carbon allocation KW - clone KW - condensed tannins KW - nutrient cycling KW - phenolics KW - productivity ER - TY - JOUR TI - Analysis of CoQ(10) in Cultivated Tobacco by a High-Performance Liquid Chromatography-Ultraviolet Method AU - Stiff, Michael R. AU - Weissinger, Arthur K. AU - Danehower, David A. T2 - JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY AB - Coenzyme Q (CoQ) is a naturally occurring lipid-soluble quinone that performs multiple functions in all living cells and has become a popular antioxidant supplement, a coadjuvant in the treatment of heart disease, and the object of study for treating neurodegenerative disorders. Although there are many tools for CoQ analysis of microbial and animal samples, there have been relatively few reports of methods for CoQ analysis of green plants. This work describes a method for the routine analysis of coenzyme Q(10) in green leaf tissue of cultivated Nicotiana tabacum (tobacco) using high-performance liquid chromatography (HPLC) with UV detection. The method was applied to the analysis of CoQ(10) in N. tabacum 'KY14' leaves at different stalk positions representing young lanceolate to senescing leaves, and it was found that CoQ(10) increased as leaf position changed down the stalk from 18.69 to 82.68 μg/g fw. The method was also used to observe CoQ(10) in N. tabacum 'NC55' and N. tabacum 'TN90LC' leaves over time, finding that CoQ(10) leaf content remained relatively stable from 3 to 6 weeks but increased in both cultivars at 8 weeks. This method will likely be useful in the analysis of CoQ(10) in the green leaves of other plant species. DA - 2011/9/14/ PY - 2011/9/14/ DO - 10.1021/jf201130z VL - 59 IS - 17 SP - 9054-9058 SN - 0021-8561 KW - ubiquinone KW - coenzyme Q KW - tobacco KW - HPLC ER - TY - JOUR TI - X-ray Microspectroscopy and Chemical Reactions in Soil Microsites AU - Hesterberg, Dean AU - Duff, Martine C. AU - Dixon, Joe B. AU - Vepraskas, Michael J. T2 - JOURNAL OF ENVIRONMENTAL QUALITY AB - Soils provide long-term storage of environmental contaminants, which helps to protect water and air quality and diminishes negative impacts of contaminants on human and ecosystem health. Characterizing solid-phase chemical species in highly complex matrices is essential for developing principles that can be broadly applied to the wide range of notoriously heterogeneous soils occurring at the earth's surface. In the context of historical developments in soil analytical techniques, we describe applications of bulk-sample and spatially resolved synchrotron X-ray absorption spectroscopy (XAS) for characterizing chemical species of contaminants in soils, and for determining the uniqueness of trace-element reactivity in different soil microsites. Spatially resolved X-ray techniques provide opportunities for following chemical changes within soil microsites that serve as highly localized chemical micro- (or nano-)reactors of unique composition. An example of this microreactor concept is shown for micro-X-ray absorption near edge structure analysis of metal sulfide oxidation in a contaminated soil. One research challenge is to use information and principles developed from microscale soil chemistry for predicting macroscale and field-scale behavior of soil contaminants. DA - 2011/5// PY - 2011/5// DO - 10.2134/jeq2010.0140 VL - 40 IS - 3 SP - 667-678 SN - 1537-2537 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79956072636&partnerID=MN8TOARS ER - TY - JOUR TI - Spectroscopic Approaches for Phosphorus Speciation in Soils and Other Environmental Systems AU - Kizewski, Fiona AU - Liu, Yu-Ting AU - Morris, Amanda AU - Hesterberg, Dean T2 - JOURNAL OF ENVIRONMENTAL QUALITY AB - In the past decades, environmental scientists have become increasingly involved in developing novel approaches for applying emerging spectroscopic techniques to complex environmental matrices. The objective of this review is to convey the most common chemical species of phosphorus reported for soils, sediments, model systems, and waste materials based on analyses by four spectroscopic techniques: X-ray absorption near-edge structure, nuclear magnetic resonance, Fourier transform infrared spectroscopy, and Raman spectroscopy. Unique information is provided by each technique at a level of specificity that depends in part on matrix complexity. The X-ray absorption near-edge structure and nuclear magnetic resonance techniques reveal inorganic and organic P species in intact environmental matrices or in chemical extracts, whereas the Fourier transform infrared and Raman techniques can provide more specific bonding information about mineral or adsorbed P species in model analogs of matrix components. The most common P species in soils and sediments as indicated by spectroscopy are hydroxyapatite and octacalcium phosphate minerals, phosphate adsorbed on Fe- and Al-oxides, pyrophosphates and polyphosphates, phosphate mono- and di-esters, and phosphonates. Continued advancements in spectroscopic methods should improve speciation-based models of P mobilization and transformations in the environment. DA - 2011/5// PY - 2011/5// DO - 10.2134/jeq2010.0169 VL - 40 IS - 3 SP - 751-766 SN - 1537-2537 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79956124868&partnerID=MN8TOARS ER - TY - JOUR TI - Soil Organic Matter Accumulation in Creeping Bentgrass Greens: A Chronosequence with Implications for Management and Carbon Sequestration AU - Carley, Danesha Seth AU - Goodman, David AU - Sermons, Shannon AU - Shi, Wei AU - Bowman, Dan AU - Miller, Grady AU - Rufty, Thomas T2 - AGRONOMY JOURNAL AB - Excessive organic matter (OM) accumulation in creeping bentgrass ( Agrostis palustris Huds.) putting greens, and its restriction of permeability, is one of the most difficult problems in turfgrass management. In this transition zone study, we characterized temporal and spatial aspects of OM accumulation, in an attempt to assess the effectiveness of management and to begin to uncover the processes controlling C sequestration. Root zone samples were collected from sand‐based putting greens at 49 golf courses of various ages, generating 212 individual observations. Organic matter accumulated hyperbolically over time in the top 2.5 cm; apparent critical levels of 40 g kg −1 were exceeded within 5 yr. At a depth of 2.5 to 7.6 cm, accumulation was much slower and linear over time, and critical levels were not reached even after 20 yr. Oxygen levels were never depressed more than 15%, indicating that intensive management of the upper soil profile was successfully allowing gas exchange into the root zone. Carbon accumulated in the soil profile hyperbolically, reflecting changes in the large OM pool near the soil surface. The sequestration rate of 59 g m −2 yr −1 over 25 yr was less than that observed by others examining soil under bentgrass greens in different environments. The evidence indicates that OM and C accumulation are strongly influenced by increasing microbial degradation rates as turfgrass systems age. DA - 2011/// PY - 2011/// DO - 10.2134/agronj2010.0335 VL - 103 IS - 3 SP - 604-610 SN - 1435-0645 ER - TY - JOUR TI - Rolled Rye Mulch for Weed Suppression in Organic No-Tillage Soybeans AU - Smith, Adam N. AU - Reberg-Horton, Chris AU - Place, George T. AU - Meijer, Alan D. AU - Arellano, Consuelo AU - Mueller, J. Paul T2 - WEED SCIENCE AB - Rising demand for organic soybeans and high price premiums for organic products have stimulated producer interest in organic soybean production. However, organic soybean producers and those making the transition to organic production cite weed management as their main limitation. Current weed management practices heavily rely on cultivation. Repeated cultivation is expensive and has negative consequences on soil health. Research is needed to improve organic reduced tillage production. Rye cover crop mulches were evaluated for weed suppression abilities and effects on soybean yield. Experiments were planted in 2008 and 2009 at three sites. Rye was planted in the fall of each year and killed at soybean planting with a roller/crimper or flail mower, creating a thick weed-suppressing mulch with potential allelopathic properties. The mulch was augmented with one of three additional weed control tactics: preemergence (PRE) corn gluten meal (CGM), postemergence (POST) clove oil, or postemergence high-residue cultivation. Roll-crimped and flail-mowed treatments had similar weed suppression abilities at most sites. There were no differences between CGM, clove oil, or cultivation at most sites. Sites with rye biomass above 9,000 kg ha −1 of dry matter provided weed control that precluded soybean yield loss from competition. In Goldsboro 2008, where rye biomass was 10,854 kg ha −1 of dry matter, the soybean yield in the rolled rye treatment was not significantly different from the weed-free treatment, yielding at 2,190 and 2,143 kg ha −1 , respectively. Likewise, no difference in soybean yield was found in Plymouth 2008 with a rye biomass of 9,256 kg ha −1 and yields of 2,694 kg ha −1 and 2,809 kg ha −1 in the rolled rye and weed-free treatments, respectively. At low rye biomass levels (4,450 to 6,606 kg ha −1 ), the rolled rye treatment soybean yield was 628 to 822 kg ha −1 less than the weed-free treatment. High rye biomass levels are critical to the success of this production system. However, high rye biomass was, in some cases, also correlated with soybean lodging severe enough to cause concern with this system. DA - 2011/// PY - 2011/// DO - 10.1614/ws-d-10-00112.1 VL - 59 IS - 2 SP - 224-231 SN - 1550-2759 KW - Cover crop mulch KW - weed suppression KW - roller/crimper KW - organic herbicides ER - TY - JOUR TI - Production of pure protein and antibodies and development of immunoassays to detect Ara h 3 levels in peanut varieties AU - Hurlburt, Barry K. AU - Schmitt, David AU - Isleib, Thomas G. AU - Cheng, Hsiaopo AU - Garvey, Cathryn AU - Koenig, Robbin L. AU - Maleki, Soheila J. T2 - INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY AB - Summary Peanuts are one of the most allergenic foods and are widespread in western food products. Therefore, there has been intense research into the allergic nature of the proteins involved. Ara h 3 is one of three immunodominant allergenic proteins. It is a 60‐kDa protein, which forms following cleavage of the preprotein and association of the resultant 40‐ and 20‐kDa subunits. The large subunit has been shown to harbour most of the reactive epitopes and has the protein fold likely responsible for its trypsin inhibitor activity. In this work, we have developed a method for the high‐level expression and purification of recombinant Ara h 3 40‐kDa subunit. Specific antibodies have been produced and applied to the secondary and tertiary screens of hundreds of peanut cultivars. Several of these cultivars were identified that have significantly reduced accumulation of Ara h 3. DA - 2011/7// PY - 2011/7// DO - 10.1111/j.1365-2621.2011.02645.x VL - 46 IS - 7 SP - 1477-1484 SN - 0950-5423 ER - TY - JOUR TI - Potential establishment of alien-invasive forest insect species in the United States: where and how many? AU - Koch, Frank H. AU - Yemshanov, Denys AU - Colunga-Garcia, Manuel AU - Magarey, Roger D. AU - Smith, William D. T2 - BIOLOGICAL INVASIONS DA - 2011/4// PY - 2011/4// DO - 10.1007/s10530-010-9883-8 VL - 13 IS - 4 SP - 969-985 SN - 1573-1464 KW - Alien-invasive species KW - Forest pests KW - Human-mediated dispersal KW - Commodity flow KW - Global trade KW - Establishment rates ER - TY - JOUR TI - Perturbation of Wood Cellulose Synthesis Causes Pleiotropic Effects in Transgenic Aspen AU - Joshi, Chandrashekhar P. AU - Thammannagowda, Shivegowda AU - Fujino, Takeshi AU - Gou, Ji-Qing AU - Avci, Utku AU - Haigler, Candace H. AU - McDonnell, Lisa M. AU - Mansfield, Shawn D. AU - Mengesha, Bemnet AU - Carpita, Nicholas C. AU - Harris, Darby AU - DeBolt, Seth AU - Peter, Gary F. T2 - Molecular Plant AB - Genetic manipulation of cellulose biosynthesis in trees may provide novel insights into the growth and development of trees. To explore this possibility, the overexpression of an aspen secondary wall-associated cellulose synthase (PtdCesA8) gene was attempted in transgenic aspen (Populus tremuloides L.) and unexpectedly resulted in silencing of the transgene as well as its endogenous counterparts. The main axis of the transgenic aspen plants quickly stopped growing, and weak branches adopted a weeping growth habit. Furthermore, transgenic plants initially developed smaller leaves and a less extensive root system. Secondary xylem (wood) of transgenic aspen plants contained as little as 10% cellulose normalized to dry weight compared to 41% cellulose typically found in normal aspen wood. This massive reduction in cellulose was accompanied by proportional increases in lignin (35%) and non-cellulosic polysaccharides (55%) compared to the 22% lignin and 36% non-cellulosic polysaccharides in control plants. The transgenic stems produced typical collapsed or ‘irregular’ xylem vessels that had altered secondary wall morphology and contained greatly reduced amounts of crystalline cellulose. These results demonstrate the fundamental role of secondary wall cellulose within the secondary xylem in maintaining the strength and structural integrity required to establish the vertical growth habit in trees. DA - 2011/3// PY - 2011/3// DO - 10.1093/mp/ssq081 VL - 4 IS - 2 SP - 331-345 J2 - Molecular Plant LA - en OP - SN - 1674-2052 UR - http://dx.doi.org/10.1093/mp/ssq081 DB - Crossref KW - Aspen KW - cellulose synthesis KW - transgenic trees KW - xylem development KW - cell wall KW - lignin KW - irregular xylem KW - growth KW - crystallinity ER - TY - JOUR TI - Multivariate analysis of maize disease resistances suggests a pleiotropic genetic basis and implicates a GST gene AU - Wisser, Randall J. AU - Kolkman, Judith M. AU - Patzoldt, Megan E. AU - Holland, James B. AU - Yu, Jianming AU - Krakowsky, Matthew AU - Nelson, Rebecca J. AU - Balint-Kurti, Peter J. T2 - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA AB - Plants are attacked by pathogens representing diverse taxonomic groups, such that genes providing multiple disease resistance (MDR) are expected to be under positive selection pressure. To address the hypothesis that naturally occurring allelic variation conditions MDR, we extended the framework of structured association mapping to allow for the analysis of correlated complex traits and the identification of pleiotropic genes. The multivariate analytical approach used here is directly applicable to any species and set of traits exhibiting correlation. From our analysis of a diverse panel of maize inbred lines, we discovered high positive genetic correlations between resistances to three globally threatening fungal diseases. The maize panel studied exhibits rapidly decaying linkage disequilibrium that generally occurs within 1 or 2 kb, which is less than the average length of a maize gene. The positive correlations therefore suggested that functional allelic variation at specific genes for MDR exists in maize. Using a multivariate test statistic, a glutathione S-transferase (GST) gene was found to be associated with modest levels of resistance to all three diseases. Resequencing analysis pinpointed the association to a histidine (basic amino acid) for aspartic acid (acidic amino acid) substitution in the encoded protein domain that defines GST substrate specificity and biochemical activity. The known functions of GSTs suggested that variability in detoxification pathways underlie natural variation in maize MDR. DA - 2011/5/3/ PY - 2011/5/3/ DO - 10.1073/pnas.1011739108 VL - 108 IS - 18 SP - 7339-7344 SN - 0027-8424 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79956318799&partnerID=MN8TOARS KW - multivariate mixed model KW - pleiotropy KW - quantitative disease resistance KW - Zea mays (maize) ER - TY - JOUR TI - Historical changes of temperature and vapor pressure deficit during the crop growing season in Iran AU - Gholipoor, M. AU - Sinclair, T. R. T2 - International Journal of Plant Production DA - 2011/// PY - 2011/// VL - 5 IS - 2 SP - 195-205 ER - TY - JOUR TI - Growth performance and antibiotic tolerance patterns of nursery and finishing pigs fed growth-promoting levels of antibiotics AU - Holt, J. P. AU - Heugten, E. AU - Graves, A. K. AU - See, M. T. AU - Morrow, W. E. M. T2 - LIVESTOCK SCIENCE AB - The objective of this study was to evaluate the impact of growth-promoting levels of antibiotics in diets for nursery and finishing pigs on growth performance and antibiotic tolerance patterns. Gilts (n = 200, initial body weight was 6.2 ± 0.003 kg), were allotted based on body weight to one of four treatments in a 2 × 2 factorial randomized complete block design. Nursery treatments consisted of feeding no antibiotics (CON) or an antibiotic diet (ANTI) containing chlortetracycline (CTC; 55 mg/kg). At the end of the nursery phase, one-half of the pigs receiving CON were switched to a diet containing antibiotic (virginiamycin; VIR, 11 mg/kg) and one-half of the pigs receiving ANTI were switched to CON for the remainder of the trial. This created four treatments for the finishing phase, consisting of: control in nursery and finishing (CC), antibiotic in nursery, control in finishing (AC), control in nursery, antibiotic in finishing (CA), or antibiotics throughout (AT). The pigs were weighed at the diet changes during the nursery (weeks 1, 3, and 5) and finishing (weeks 7, 9, 13, 17, and 20) phases. Fecal samples were collected at all diet changes for isolation of fecal coliforms and Enterococcus and subsequently tested for tolerance to CTC and VIR. After 1 week, CON pigs weighed less (7.09 vs. 7.28 kg) and had lower ADG (149 vs. 180 g/day) and ADFI (174 vs. 192 g/day) than ANTI pigs (P < 0.05). No performance differences were observed during the remainder of the study. At the initiation of the study (week 0), the ability of coliforms to grow in the presence of CTC and VIR, respectively, were 68 and 73% and increased to 90 and 96% at week 19 (time effect, P < 0.001). At week 17, tolerance of coliforms to CTC was greater for CA (98%) than AC (86%, time × treatment effect, P < 0.004). Enterococcus tolerance to CTC at week 7 was lower for CC (55%) compared to AT (76%), AC (74%) and CA (83%, time × treatment effect, P < 0.001). At week 9, Enterococcus tolerant to CTC and VIR, respectively, was lower for CC (15 and 18%) than AT (31 and 40%), AC (35 and 35%), and CA (44 and 43%, time × treatment effect, P < 0.001). Antibiotic growth promoters had little impact on growth performance in clean, isolated facilities with high labor inputs. The tolerance of bacteria to antibiotics fluctuated over time and persisted regardless of the use of antibiotic growth promoters. DA - 2011/4// PY - 2011/4// DO - 10.1016/j.livsci.2010.09.007 VL - 136 IS - 2-3 SP - 184-191 SN - 1878-0490 KW - Antibiotics KW - Growth performance KW - Swine ER - TY - JOUR TI - Genetic Improvement of the Pee Dee Cotton Germplasm Collection following Seventy Years of Plant Breeding AU - Campbell, B. T. AU - Chee, P. W. AU - Lubbers, E. AU - Bowman, D. T. AU - Meredith, W. R., Jr. AU - Johnson, J. AU - Fraser, D. E. T2 - CROP SCIENCE AB - One of the most significant, long‐term public U.S. Upland cotton ( Gossypium hirsutum L.) germplasm enhancement programs is known as the Pee Dee germplasm program. The unique, genetic foundation of the Pee Dee germplasm was created using germplasm from Upland, Sea Island ( Gossypium barbadense L.), and primitive diploid cottons. Since the program's inception in 1935, the Pee Dee germplasm program has released >80 improved germplasm lines and cultivars. In this study, the agronomic and fiber quality performance of Pee Dee germplasm was evaluated across southeastern U.S. environments to estimate genetic improvement within the Pee Dee germplasm program. Results suggest that the Pee Dee germplasm enhancement program has (i) maintained usable genetic variation and (ii) maintained high fiber quality potential while concomitantly improving agronomic performance. Although the results highlight the need to continue improving lint percent, lint yield, and bolls m −2 , there is also evidence to suggest that Pee Dee germplasm can continue being utilized to develop the next generation of high‐fiber‐quality and high‐yielding cotton cultivars. DA - 2011/5// PY - 2011/5// DO - 10.2135/cropsci2010.09.0545 VL - 51 IS - 3 SP - 955-968 SN - 1435-0653 ER - TY - JOUR TI - Exotic Scab Resistance Quantitative Trait Loci Effects on Soft Red Winter Wheat AU - Kang, Jing AU - Clark, Anthony AU - Van Sanford, David AU - Griffey, Carl AU - Brown-Guedira, Gina AU - Dong, Yanhong AU - Murphy, J. Paul AU - Costa, Jose T2 - CROP SCIENCE AB - ABSTRACT Fusarium head blight (FHB), caused by Fusarium graminearum , of wheat ( Triticum aestivum L.) is a disease that periodically strikes the mid‐Atlantic region of the United States. Breeding for resistant wheat varieties is an effective method of disease control. The objective of this study was to evaluate the effects of exotic FHB resistance quantitative trait loci (QTL), singly and in combination, on FHB resistance in soft red winter wheat (SRWW). Three FHB resistance QTL on chromosomes 3BS ( Fhb1 ), 2D, and 5A were introgressed from nonadapted Chinese cultivar Ning7840 into the adapted SRWW cultivar McCormick. Eight near‐isogenic lines (NIL) were developed by marker‐assisted backcrossing. The NIL that combined 3BS and 2DL expressed the highest resistance and lowest deoxynivalenol (DON) content in four environments that included three field and one greenhouse studies. These results indicate that the combination of just two QTL (3BS and 2DL) would be useful to breed for improved FHB resistance in SRWW in the mid‐Atlantic region. DA - 2011/5// PY - 2011/5// DO - 10.2135/cropsci2010.06.0313 VL - 51 IS - 3 SP - 924-933 SN - 0011-183X ER - TY - JOUR TI - Delignification of switchgrass cultivars for bioethanol production AU - Xu, J. L. AU - Chen, Y. AU - Cheng, J. J. AU - Sharma-Shivappa, R. R. AU - Burns, J. C. T2 - BioResources DA - 2011/// PY - 2011/// VL - 6 IS - 1 SP - 707-720 ER - TY - JOUR TI - Benchmark study on glyphosate-resistant cropping systems in the United States. Part 6: Timeliness of economic decision-making in implementing weed resistance management strategies AU - Weirich, Jason W. AU - Shaw, David R. AU - Coble, Keith H. AU - Owen, Micheal D. K. AU - Dixon, Philip M. AU - Weller, Stephen C. AU - Young, Bryan G. AU - Wilson, Robert G. AU - Jordan, David L. T2 - PEST MANAGEMENT SCIENCE AB - Abstract BACKGROUND: The introduction of glyphosate‐resistant (GR) crops in the late 1990s made weed control in maize, cotton and soybean simple. With the rapid adoption of GR crops, many growers began to rely solely on glyphosate for weed control. This eventually led to the evolution of GR weeds. Growers are often reluctant to adopt a weed resistance best management practice (BMP) because of the added cost of additional herbicides to weed control programs which would reduce short‐term revenue. This study was designed to evaluate when a grower that is risk neutral (profit maximizing) or risk averse should adopt a weed resistance BMP. RESULTS: Whether a grower is risk neutral or risk averse, the optimal decision would be to adopt a weed resistance BMP when the expected loss in revenue is greater than 30% and the probability of resistance evolution is 0.1 or greater. However, if the probability of developing resistance increases to 0.3, then the best decision would be to adopt a weed resistance BMP when the expected loss is 10% or greater. CONCLUSION: Given the scenarios analyzed, risk‐neutral or risk‐averse growers should implement a weed resistance BMP with confidence that they have made the right decision economically and avoided the risk of lost revenue from resistance. If the grower wants to continue to see the same level of return, adoption of BMP is required. Copyright © 2011 Society of Chemical Industry DA - 2011/7// PY - 2011/7// DO - 10.1002/ps.2175 VL - 67 IS - 7 SP - 785-789 SN - 1526-498X KW - resistance management KW - glyphosate KW - glyphosate resistance KW - glyphosate-resistant crops ER - TY - JOUR TI - Benchmark study on glyphosate-resistant cropping systems in the United States. Part 5: Effects of glyphosate-based weed management programs on farm-level profitability AU - Weirich, Jason W. AU - Shaw, David R. AU - Owen, Micheal D. K. AU - Dixon, Philip M. AU - Weller, Stephen C. AU - Young, Bryan G. AU - Wilson, Robert G. AU - Jordan, David L. T2 - PEST MANAGEMENT SCIENCE AB - Abstract BACKGROUND: Glyphosate‐resistant (GR) crops have changed the way growers manage weeds and implement control strategies. Since the introduction of GR crops, growers in many instances have relied on glyphosate almost exclusively to control a broad spectrum of weeds. This overreliance on glyphosate has resulted in the evolution of glyphosate resistance in some weed species. Growers and scientists are concerned about the sustainability of GR crops and glyphosate. When a grower is making decisions about weed control strategies, economic costs and benefits of the program are primary criteria for selection and implementation. Studies across six states were initiated in 2006 to compare the economics of using a weed resistance best management practice (BMP) system with a grower's standard production system. RESULTS: Resistance BMP systems recommended by university scientists were more costly but provided similar yields and economic returns. Rotation of GR crops resulted in a higher net return (maize and soybean) compared with continuous GR crop (cotton or soybean) or rotating a GR crop with a non‐GR crop (maize). CONCLUSION: Growers can implement weed resistance BMP systems with the confidence that their net returns will be equivalent in the short run, and, in the long term, resistance BMP systems will prevent or delay the evolution of GR weeds in their fields, resulting in substantial savings. Copyright © 2011 Society of Chemical Industry DA - 2011/7// PY - 2011/7// DO - 10.1002/ps.2177 VL - 67 IS - 7 SP - 781-784 SN - 1526-498X KW - resistance management KW - glyphosate KW - glyphosate resistance KW - glyphosate-resistant crops KW - economic benefit ER - TY - JOUR TI - Benchmark study on glyphosate-resistant cropping systems in the United States. Part 4: Weed management practices and effects on weed populations and soil seedbanks AU - Wilson, Robert G. AU - Young, Bryan G. AU - Matthews, Joseph L. AU - Weller, Stephen C. AU - Johnson, William G. AU - Jordan, David L. AU - Owen, Micheal D. K. AU - Dixon, Philip M. AU - Shaw, David R. T2 - PEST MANAGEMENT SCIENCE AB - Abstract BACKGROUND: Weed management in glyphosate‐resistant (GR) maize, cotton and soybean in the United States relies almost exclusively on glyphosate, which raises criticism for facilitating shifts in weed populations. In 2006, the benchmark study, a field‐scale investigation, was initiated in three different GR cropping systems to characterize academic recommendations for weed management and to determine the level to which these recommendations would reduce weed population shifts. RESULTS: A majority of growers used glyphosate as the only herbicide for weed management, as opposed to 98% of the academic recommendations implementing at least two herbicide active ingredients and modes of action. The additional herbicides were applied with glyphosate and as soil residual treatments. The greater herbicide diversity with academic recommendations reduced weed population densities before and after post‐emergence herbicide applications in 2006 and 2007, particularly in continuous GR crops. CONCLUSION: Diversifying herbicides reduces weed population densities and lowers the risk of weed population shifts and the associated potential for the evolution of glyphosate‐resistant weeds in continuous GR crops. Altered weed management practices (e.g. herbicides or tillage) enabled by rotating crops, whether GR or non‐GR, improves weed management and thus minimizes the effectiveness of only using chemical tactics to mitigate weed population shifts. Copyright © 2011 Society of Chemical Industry DA - 2011/7// PY - 2011/7// DO - 10.1002/ps.2176 VL - 67 IS - 7 SP - 771-780 SN - 1526-4998 KW - corn KW - cotton KW - genetically engineered crops KW - genetically modified crops KW - herbicide-tolerant crops KW - herbicide-resistant weeds KW - maize KW - resistance management KW - soybean KW - weed seedbank ER - TY - JOUR TI - Benchmark study on glyphosate-resistant cropping systems in the United States. Part 3: Grower awareness, information sources, experiences and management practices regarding glyphosate-resistant weeds AU - Givens, Wade A. AU - Shaw, David R. AU - Newman, Michael E. AU - Weller, Stephen C. AU - Young, Bryan G. AU - Wilson, Robert G. AU - Owen, Micheal D. K. AU - Jordan, David L. T2 - PEST MANAGEMENT SCIENCE AB - A survey was conducted with nearly 1200 growers in US states (Illinois, Indiana, Iowa, Mississippi, Nebraska and North Carolina) in 2005 with the objective in part of determining the awareness of the potential for development of glyphosate resistance, the experience with glyphosate-resistant (GR) weeds and the sources of information that growers had utilized for information on glyphosate resistance. Growers were asked a series of questions to determine the level of glyphosate resistance awareness and to list the sources of information used to learn about glyphosate resistance issues.The majority of the growers (88%) were aware of a weed's potential to evolve resistance to herbicide, while 44% were aware of state-specific documented cases of GR weeds, and 15% reported having had personal experience with GR weeds. Among sources of information concerning glyphosate resistance issues, farm publications, dealers/retailers and university/extension were the most frequent responses (41, 17 and 14% respectively). Based on a 1-10 effectiveness scale, growers ranked tillage the least effective practice (5.5) and using the correct label rates of herbicides at the proper timing for the size and type of weeds present the most effective practice (8.6) with respect to how effectively the practices mitigated the evolution of GR weeds.Results from this survey can be used by researchers, extension specialists and crop advisors further to bridge the information gap between growers and themselves and better to disseminate information concerning glyphosate resistance and glyphosate resistance management practices through more targeted information and information delivery methods. DA - 2011/7// PY - 2011/7// DO - 10.1002/ps.2178 VL - 67 IS - 7 SP - 758-770 SN - 1526-4998 KW - glyphosate KW - glyphosate resistance KW - grower survey KW - resistance management ER - TY - JOUR TI - Benchmark study on glyphosate-resistant cropping systems in the United States. Part 1: Introduction to 2006-2008 AU - Shaw, David R. AU - Owen, Micheal D. K. AU - Dixon, Philip M. AU - Weller, Stephen C. AU - Young, Bryan G. AU - Wilson, Robert G. AU - Jordan, David L. T2 - PEST MANAGEMENT SCIENCE AB - Glyphosate-resistant (GR) crop technology has dramatically impacted agriculture. The adoption of GR systems in canola, maize, cotton, soybean and sugar beets has been widespread in the United States. However, weed scientists are concerned that growers' current herbicide programs and weed management tactics will affect their sustainability and effectiveness. Without proper management, the potential for weed populations to express a high degree of resistance to glyphosate will adversely impact the utility of glyphosate. In 2005, weed scientists from six universities initiated a long-term research study to assess the sustainability of GR technology. This paper introduces five other articles in this series. Over 150 fields of at least 10 ha were selected to participate in a long-term field-scale study, and each field was split in half. On one-half the grower continued using the current weed management program; on the other half the grower used academic-recommended herbicide resistance best management practices. Field data were collected in 2006-2008 to determine the impact of the two weed management programs on weed populations, diversity, seedbank, crop yields and economic returns. This long-term study will provide invaluable data for determining the sustainability and profitability of diversified weed management programs designed to lower the risk of evolving weed resistance to glyphosate. DA - 2011/7// PY - 2011/7// DO - 10.1002/ps.2160 VL - 67 IS - 7 SP - 741-746 SN - 1526-498X KW - glyphosate KW - glyphosate resistance KW - glyphosate-resistant crops KW - resistance management KW - survey ER - TY - JOUR TI - Benchmark study on glyphosate-resistant crop systems in the United States. Part 2: Perspectives AU - Owen, Micheal D. K. AU - Young, Bryan G. AU - Shaw, David R. AU - Wilson, Robert G. AU - Jordan, David L. AU - Dixon, Philip M. AU - Weller, Stephen C. T2 - PEST MANAGEMENT SCIENCE AB - Abstract A six‐state, 5 year field project was initiated in 2006 to study weed management methods that foster the sustainability of genetically engineered (GE) glyphosate‐resistant (GR) crop systems. The benchmark study field‐scale experiments were initiated following a survey, conducted in the winter of 2005–2006, of farmer opinions on weed management practices and their views on GR weeds and management tactics. The main survey findings supported the premise that growers were generally less aware of the significance of evolved herbicide resistance and did not have a high recognition of the strong selection pressure from herbicides on the evolution of herbicide‐resistant (HR) weeds. The results of the benchmark study survey indicated that there are educational challenges to implement sustainable GR‐based crop systems and helped guide the development of the field‐scale benchmark study. Paramount is the need to develop consistent and clearly articulated science‐based management recommendations that enable farmers to reduce the potential for HR weeds. This paper provides background perspectives about the use of GR crops, the impact of these crops and an overview of different opinions about the use of GR crops on agriculture and society, as well as defining how the benchmark study will address these issues. Copyright © 2011 Society of Chemical Industry DA - 2011/7// PY - 2011/7// DO - 10.1002/ps.2159 VL - 67 IS - 7 SP - 747-757 SN - 1526-4998 KW - glyphosate KW - glyphosate resistance KW - glyphosate-resistant crops KW - selection pressure KW - genetically engineered crops ER - TY - JOUR TI - Allelic Effect Variation at Key Photoperiod Response Quantitative Trait Loci in Maize AU - Coles, N. D. AU - Zila, C. T. AU - Holland, J. B. T2 - CROP SCIENCE AB - Tropical maize ( Zea mays L.) represents a valuable genetic resource containing unique alleles not present in elite temperate maize. The strong delay in flowering in response to long daylength photoperiods exhibited by most tropical maize hinders its incorporation into temperate maize breeding programs. We tested the hypothesis that diverse tropical inbreds carry alleles with similar effects at four key photoperiod response quantitative trait loci (QTL) previously identified in maize. Four tropical maize inbreds were each crossed and backcrossed twice to the temperate recurrent parent B73 to establish four sets of introgression lines. Evaluation of these lines under long daylengths demonstrated that all four QTL have significant effects on flowering time or height in these lines, but the functional allelic effects varied substantially across the tropical donor lines. At the most important photoperiod response QTL on chromosome 10, one tropical line allele even promoted earlier flowering relative to the B73 allele. Significant allelic effect differences among tropical founders were also demonstrated directly in an F 2 population derived from the cross of Ki14 and CML254. The chromosome 10 photoperiod response QTL position was validated in a set of heterogeneous inbred families evaluated in field tests and in controlled environments. DA - 2011/5// PY - 2011/5// DO - 10.2135/cropsci2010.08.0488 VL - 51 IS - 3 SP - 1036-1049 SN - 1435-0653 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79955539611&partnerID=MN8TOARS ER - TY - JOUR TI - Technical note: Use of near-infrared reflectance spectroscopy to predict intake and digestibility in bulls and steers AU - Huntington, G. B. AU - Leonard, E. S. AU - Burns, J. C. T2 - JOURNAL OF ANIMAL SCIENCE AB - Multiple fecal samples were collected from growing Angus bulls (264 to 419 kg of BW, 3.0 to 11.4 kg/d of DMI) to predict DMI of a corn-silage-based diet. Contemporaneous digestion trials were conducted with the same diet in 12 steers in yr 1 to 3 and bulls in yr 4. Near-infrared spectra from fecal samples (n = 730 from 282 growing bulls, n = 240 from 36 steers and 12 bulls for digestion trials) were obtained from dried and ground fecal samples, and modified partial least squares regression was used to develop equations to predict DMI and DM digestibility (DMD). Although mean predicted DMI of the growing bulls (7.52 ± 0.04 kg/d or 22.4 ± 0.1 g/kg of BW) was within 2% of mean measured DMI (7.63 ± 0.06 kg/d or 22.7 ± 0.1 g/kg of BW), the mean of paired differences within samples (0.11 ± 0.04 kg/d or 0.3 ± 0.1 g/kg of BW) was greater (P < 0.01) than zero. Measured DMD (72.3 ± 0.5%) was identical (P < 0.97) to predicted DMD (72.3 ± 0.5%), and DMD for bulls in the digestion trial did not differ (P < 0.27) from DMD for steers. Prediction of intake requires incorporation of some measured values from the set of fecal samples to be predicted. Lack of similarity between spectra of fecal grab samples from the growing bulls and daily fecal collection of steers and bulls in the digestion trials in this study indicates the need for further verification before prediction of DMD with fecal grab samples. DA - 2011/4// PY - 2011/4// DO - 10.2527/jas.2010-3376 VL - 89 IS - 4 SP - 1163-1166 SN - 1525-3163 KW - bull KW - corn silage KW - digestion KW - intake KW - near-infrared reflectance KW - steer ER - TY - JOUR TI - Tall Fescue Forage Mass and Canopy Characteristics on Steer Ingestive Behavior and Performance AU - Burns, J. C. AU - Fisher, D. S. AU - Pond, K. R. T2 - CROP SCIENCE AB - ABSTRACT Tall fescue ( Festuca arundinacea Schreb.) is a well‐adapted perennial pasture species utilized across the north–south transition zone of the United States. This 3‐yr trial evaluated the influence of three forage masses (FM) on steer and pasture responses for spring (April to July) and fall (October) growths. Spring FM averaged 1450 kg ha −1 (Short), 3032 kg ha −1 (Medium), and 3812 kg ha −1 (Tall) for the three treatments. Canopy in vitro true organic matter disappearance (ITOD) decreased linearly from Short (797 g kg −1 ) to Tall (771 g kg −1 ). Steer daily gains (0.88 kg) and gains per hectare (392 kg ha −1 yr −1 ) were not altered by FM, but the mean number of steers per hectare decreased linearly from Short (8.2 steers ha −1 ) to Tall (6.1 steers ha −1 ) as did effective feed units per hectare (2256 to 1712 kg ha −1 yr −1 ). Canopies were predominately leaf (53%) and averaged 847 g kg −1 ITOD with estimates similar among FM treatments. Diet ITOD declined linearly from Short (870 g kg −1 ) to Tall (839 g kg −1 ) as did crude protein (CP) (from 235 to 192 g kg −1 ). In the fall, FM averaged 1556, 3228, and 3494 kg ha −1 for the three FM treatments. Canopy ITOD averaged 774 g kg −1 and was not altered by FM. Canopy leaves averaged 60% with an ITOD of 864 g kg −1 and were similar among FM treatments. Diets selected averaged 834 g kg −1 ITOD and 233 g kg −1 CP and were not altered by FM. Tall fescue pasture free of toxic endophyte needs to be effectively utilized to enhance production and can be managed flexibly in grazing systems. DA - 2011/7// PY - 2011/7// DO - 10.2135/cropsci2010.10.0578 VL - 51 IS - 4 SP - 1850-1864 SN - 1435-0653 ER - TY - JOUR TI - Steer performance, intake, and digesta kinetics of switchgrass at three forage masses AU - Burns, J. C. AU - Fisher, D. S. AU - Pond, K. R. T2 - Agronomy Journal AB - Management strategies to accommodate switchgrass ( Panicum virgatum L.) in production systems have been reported but impact of variation in forage mass (FM) on animal responses and pasture stands are lacking. This 4‐yr study assessed canopy and stand characteristic and steer ( Bos taurus ) responses when ‘Kanlow’ switchgrass was continuously and variably stocked to produce Short (S) (10–16 cm), Medium (M) (20–26 cm), and Tall (T) (35–41 cm) canopy heights. From April to mid‐July (Period 1) FM for S, M, and T average 818, 2164, and 3294 kg ha −1 , respectively. Canopies had similar in vitro organic matter disappearance (IVOMD) (626 g kg −1 ), but increased in neutral detergent fiber (NDF) from S (645 g kg −1 ) to T (665 g kg −1 ). Diets decreased in IVOMD from S (744 g kg −1 ) to T (706 g kg −1 ). Digesta kinetics data were not altered and average daily gain was similar among FM (1.11 kg d −1 ). From mid‐July to late September (Period 2), FM averaged 465, 1282, and 2388 kg ha −1 , respectively, for S, M, and T. Whole canopy IVOMD increased from S (484 g kg −1 ) to T (538 g kg −1 ), whereas NDF was not altered (696 g kg −1 ). Steers selected a diet similar in IVOMD (685 g kg −1 ) and NDF (667 g kg −1 ) among FM. Estimates of dry matter intake (kg 100 −1 kg body weight) increased from S (1.75) to T (2.54). Tiller density decreased from T to S. Continuously stocked switchgrass at 20 to 40 cm remained vegetative with 1279 tillers m −2 after 3 yr of grazing. DA - 2011/// PY - 2011/// DO - 10.2134/agronj2010.0357 VL - 103 IS - 2 SP - 337-350 ER - TY - JOUR TI - Soybean Plastidal Omega-3 Fatty Acid Desaturase Genes GmFAD7 and GmFAD8: Structure and Expression AU - Upchurch, Robert G. AU - Ramirez, Martha E. T2 - CROP SCIENCE AB - ABSTRACT We characterized soybean [ Glycine max (L.) Merr.] FAD7 and FAD8 gene structure and expression responses to temperature and pathogen stress to compare and contrast these features to those reported for higher plant plastidal omega‐3 (ω‐3) desaturases. We found that the genomic structure and deduced amino acid sequence of soybean FAD7 and FAD8 are similar to other higher plant plastidal ω‐3 desaturases: eight exons and seven introns, predicted proteins of 453 amino acid residues containing three conserved histidine motifs, amino terminal chloroplast transit peptides, and molecular masses of 51.3 and 51.4 kDa, respectively. GmFAD7 has 76% amino acid sequence identity to GmFAD8 . Two complete copies of GmFAD7 , one on chromosome 18 and one on chromosome 7, and two complete copies of GmFAD8, one on chromosome 3 and one on chromosome 1 of the ‘Williams 82’ soybean genome, were found with strong sequence similarity to GmFAD7 and GmFAD8 of cultivar Dare. Dare GmFAD7 transcript expression in leaves remained at a relatively low level and was unaffected by any of the temperature treatments we imposed, but GmFAD8 transcript accumulation was sharply upregulated by a cool temperature (20/16°C day/night) after a 12 h exposure and total linolenic acid as a percent of total leaf fatty acids increased from 60 to about 68% after 48 h at the cool temperature. Inoculation of soybean leaves with the fungal pathogen Cercospora kikuchii differentially upregulated the level of GmFAD7 transcripts to twice that of GmFAD8 by 12 h postinoculation. The response of soybean foliar FAD8 expression and linolenic acid levels to cool temperature was similar to observations in other plants. On the other hand, despite increased soybean FAD7 expression in response to foliar pathogen stress the expected associated increase in foliar linolenic acid was not detected. DA - 2011/7// PY - 2011/7// DO - 10.2135/cropsci2010.09.0537 VL - 51 IS - 4 SP - 1673-1682 SN - 1435-0653 ER - TY - JOUR TI - Seed Dormancy in Mexican Teosinte AU - Avendano Lopez, Adriana Natividad AU - Sanchez Gonzalez, Jose de Jesus AU - Ruiz Corral, Jose Ariel AU - De La Cruz Larios, Lino AU - Santacruz-Ruvalcaba, Fernando AU - Sanchez Hernandez, Carla Vanessa AU - Holland, James B. T2 - CROP SCIENCE AB - Seed dormancy in wild Zea species may affect fitness and relate to ecological adaptation. The primary objective of this study was to characterize the variation in seed germination of the wild species of the genus Zea that currently grow in México and to relate this variation to their ecological zones of adaptation. In addition, we compared methods to break dormancy and measured the germination responses of seeds to environment factors that are related to seasonal changes. Teosinte populations representing all the taxonomic and racial groups known in México were collected during the period 2003 to 2008 in twelve states of México. Seed dormancy was classified according to the rate of its loss (depth of dormancy). Results indicated that more than 90% of populations studied had some degree of seed dormancy. Nondormant populations are distributed predominantly in semicold areas, while deep and very deep seed dormancy was found in populations distributed in hot and very hot environments in well defined geographic regions of the Balsas River Basin and in San Felipe Usila, Oaxaca. Mechanical seed scarification was the best method to break dormancy. DA - 2011/9// PY - 2011/9// DO - 10.2135/cropsci2010.09.0538 VL - 51 IS - 5 SP - 2056-2066 SN - 1435-0653 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79961182540&partnerID=MN8TOARS ER - TY - JOUR TI - Registration of Maize Inbred Line GT603 AU - Guo, B. Z. AU - Krakowsky, M. D. AU - Ni, X. AU - Scully, B. T. AU - Lee, R. D. AU - Coy, A. E. AU - Widstrom, N. W. T2 - JOURNAL OF PLANT REGISTRATIONS AB - GT603 (Reg. No. GP‐577, PI 659665) is an inbred line of yellow dent maize ( Zea mays L.) developed and released in 2010 by the USDA‐ARS Crop Protection and Management Research Unit in cooperation with the University of Georgia Coastal Plain Experiment Station. GT603 was developed through seven generations of self‐pollination from the maize population GT‐MAS:gk (PI 561859), which was released as a source of resistance to Aspergillus flavus Link:Fr. GT603 was initially selected from early self‐pollinated lines under the experimental name GT‐P50. Laboratory and field studies demonstrated that GT603 had aflatoxin levels similar to or lower than the related inbred lines GT601 (PI 644026) and GT602 (PI 644027) and the controls Mp313E (PI539859) and Mp715 (PI614819), but it matured earlier than Mp313E and Mp715. The line GT603 is phenotypically different (darker cob and kernel colors and better agronomic traits) from the related lines GT601 and GT602 although the source of resistance may be the same. In hybrid performance tests in 2005 and 2009, GT603 exhibited better combining ability and heterosis with the Stiff Stalk Synthetic (SSS) inbred (B73) than with the non‐SSS inbred (Mo17) for aflatoxin level and grain yield. DA - 2011/5// PY - 2011/5// DO - 10.3198/jpr2010.08.0386crg VL - 5 IS - 2 SP - 211-214 SN - 1940-3496 ER - TY - JOUR TI - Phosphorus leaching in a sandy soil as affected by organic and inorganic fertilizer sources AU - Kang, Jihoon AU - Amoozegar, Aziz AU - Hesterberg, Dean AU - Osmond, Deanna L. T2 - GEODERMA AB - Long-term application of phosphorus (P) to soils as fertilizer or manure can increase the potential for P loss to ground and surface waters. Vertical P transport was investigated in a sandy soil material receiving seven different P fertilizer sources: poultry compost, poultry litter, triple superphosphate [Ca(H2PO4)2·H2O], dairy lagoon liquid, swine lagoon liquid, swine lagoon sludge, and dissolved potassium dihydrogen phosphate (KH2PO4). The P sources were surface-applied to soil columns (6.35-cm diameter, 10-cm long) at two rates equivalent to 75 and 150 kg total P ha−1, and columns were intermittently leached with deionized (DI) water. Column effluents were collected for up to 23 pore volumes and analyzed for dissolved reactive phosphorus (DRP) and dissolved organic carbon (DOC). In addition, a P retardation factor was determined for the soil from a P adsorption isotherm. Transport of P through soil columns receiving liquid P sources was simulated by a one-dimensional equilibrium convective–dispersive equation (CDE) based on water-extractable P (WEP) concentrations. Cumulative amounts of DRP leached were linearly related to the amounts of WEP in P source materials (r2 = 0.87***). The recovery of DRP in the column effluents relative to WEP in the applied materials was 126 ± 15% (mean ± standard error) for organic P sources and 66 ± 2% for inorganic P sources. The use of WEP in the CDE model underpredicted P transport in the columns amended with lagoon liquids compared with dissolved KH2PO4. Results indicated that leaching losses of P from land-applied manures exceed the amounts of WEP in source materials because of organic P mineralization and competitive sorption of DOC. DA - 2011/3/15/ PY - 2011/3/15/ DO - 10.1016/j.geoderma.2010.12.019 VL - 161 IS - 3-4 SP - 194-201 SN - 0016-7061 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79951581004&partnerID=MN8TOARS KW - Adsorption KW - Leaching KW - Organic carbon KW - Phosphorus KW - Water quality ER - TY - JOUR TI - Phosphate Bonding on Noncrystalline Al/Fe-Hydroxide Coprecipitates AU - Liu, Yu-Ting AU - Hesterberg, Dean T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Poorly crystalline minerals have high sorption capacities for environmentally important chemical species, but molecular-level mechanisms of sorption on complex mineral assemblages remain largely unknown. We determined the distribution of orthophosphate (PO(4)) bonding between Al and Fe in relation to structural properties of Al/Fe-hydroxide coprecipitates. Phosphate was sorbed at concentrations between 0.042 and 0.162 mol P mol(-1) Al+Fe on coprecipitates containing 0, 20, 50, 75, or 100 mol % of metal as Al. Phosphorus XANES analyses showed preferential bonding of PO(4) for Al on coprecipitates with 20 and 50 mol % Al, and no preference for either metal at 75 mol % Al, consistent with X-ray photoelectron spectroscopy (XPS) analyses of near-surface metal distributions. Structural ordering and the Fe-hydroxide domain size in coprecipitates decreased with increasing Al proportion, as shown by X-ray diffraction (XRD) and Fe EXAFS analyses. Structural interactions in coprecipitates imparted unique PO(4) sorption properties compared with isolated Al- or Fe-hydroxide. DA - 2011/8/1/ PY - 2011/8/1/ DO - 10.1021/es201597j VL - 45 IS - 15 SP - 6283-6289 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79960947486&partnerID=MN8TOARS ER - TY - JOUR TI - Molecular Characterization of the Mutant fap3(A22) Allele for Reduced Palmitate Concentration in Soybean AU - De Vries, Brian D. AU - Fehr, Walter R. AU - Welke, Grace A. AU - Dewey, Ralph E. T2 - CROP SCIENCE AB - ABSTRACT Reduction of the palmitate concentration in soybean [ Glycine max (L.) Merr.] oil is desirable for reducing the amount of saturated fat in the human diet. Chemical mutagenesis was used to develop the line A22 with the mutant allele designated fap3 (A22) that reduces palmitate concentration in the seed oil. The objective of our study was to determine the molecular basis of the fap3 (A22) mutation and develop a corresponding molecular marker to assist in future efforts for developing soybean cultivars with low saturated fat. DNA sequence analysis of the GmFATB1a gene of soybean revealed a single nucleotide polymorphism (SNP) resulting in a nonconservative amino acid substitution that was likely to be detrimental to the function of the 16:0–acyl carrier protein (ACP) thioesterase (TE) enzyme. An association analysis was conducted using F 2 –derived lines from a cross between the cultivar Archer ( Fap3Fap3 ) and A22 ( fap3fap3 ) that had been analyzed for their palmitate concentration by gas chromatography. Molecular genotyping of these lines established a perfect correlation between lines phenotypically classified as homozygous for the Fap3 allele or homozygous for the fap3 (A22) allele based on their palmitate concentration. The polymorphism in the GmFATB1a gene was used to develop a functional, codominant marker that could be used to distinguish the Fap3 and fap3 (A22) alleles in segregating populations. This marker will be useful for breeders who are developing low‐saturate cultivars with the fap3 (A22) allele. DA - 2011/7// PY - 2011/7// DO - 10.2135/cropsci2010.10.0619 VL - 51 IS - 4 SP - 1611-1616 SN - 0011-183X ER - TY - JOUR TI - Molecular Analysis of GmFAD3A in Two Soybean Populations Segregating for the fan, fap1, and fap(nc) Loci AU - Cardinal, Andrea J. AU - Burton, Joseph W. AU - Camacho-Roger, Ana Maria AU - Whetten, Rebecca AU - Chappell, Andrew S. AU - Bilyeu, Kristin D. AU - Auclair, Jerome AU - Dewey, Ralph E. T2 - CROP SCIENCE AB - Soybeans [ Glycine max (L.) Merr.] have undesirable levels of polyunsaturated fatty acids in their oil that result in oxidative instability and poor flavor. The process of hydrogenation improves the stability but creates undesirable trans fats. Lines carrying fan genes have decreased linolenic acid (18:3) content. Changes in transcription or activity of the desaturase encoded by the GmFAD3 gene cause a reduction in 18:3 content in certain lines. The objectives of this study were to determine the molecular basis of the fan allele in PI 123440, develop molecular markers to assay for the GmFAD3 gene in lines carrying fan (PI 123440), and estimate the variation in the 18:3 explained by the GmFAD3A locus. Sequence analysis of the GmFAD3A from ‘Soyola’, the fan (PI 123440) allele, and ‘Dare’ showed no sequence polymorphisms that would alter the amino acid sequence of the enzyme. RNA blot analysis of a low‐18:3 line carrying a fan (PI 123440) allele, a line with normal 18:3 content, and three of their progenies showed a decrease in steady‐state FAD3A RNA levels in low‐18:3 lines. A marker for GmFAD3A was tested in two populations segregating for fan (PI 123440). Lines homozygous the GmFAD3A allele inherited from PI 123440 had a significant reduction in 18:3 when compared to lines homozygous for the GmFAD3A allele from the normal 18:3 parent. The differences between the two groups explained more than 77.5% of the genetic variation in 18:3 seed‐oil content in the populations. In summary, a reduction in the steady‐state mRNA levels of the GmFAD3A leads to a reduction in 18:3 synthesis within the developing seed in plants containing the fan (PI 123440) allele. DA - 2011/9// PY - 2011/9// DO - 10.2135/cropsci2010.08.0500 VL - 51 IS - 5 SP - 2104-2112 SN - 1435-0653 ER - TY - JOUR TI - Maturity and Regrowth Influences on Quality of Caucasian Bluestem Hay AU - Burns, J. C. T2 - CROP SCIENCE AB - ABSTRACT Caucasian bluestem [CBS; Bothriochloa caucasica (Trin.) C.E. Hubbard ‘Caucasian’] appears adapted to the mid‐Atlantic region. Three experiments, one with sheep and two with steers, were conducted to assess hay quality. In Experiment (Exp.) 1, initial growth was cut at early boot, anthesis, and postanthesis and regrowth cut at early boot and anthesis (five treatments) and evaluated by wether sheep. All treatments, except regrowth anthesis were also evaluated in a preliminary experiment with steers. In Exp. 2, regrowth was cut at the same three initial growth stages as in Exp. 1 and evaluated by steers. Sheep readily ate CBS hay, consuming 1.88 kg 100 kg −1 body weight (BW) when the hay was cut at early boot, with apparent dry matter digestion (DMD) of 647 g kg −1 . Intake decreased linearly by postanthesis to 1.45 kg 100 kg −1 BW with DMD of 548 g kg −1 . Steers also readily ate early‐boot CBS hay, averaging 2.49 kg 100 kg −1 BW with DMD of 661 g kg −1 . Intake decreased linearly by postanthesis to 1.48 kg 100 kg −1 BW with a DMD of 589 g kg −1 . Sheep and steer intake was well correlated ( r = 0.951; P = 0.05) as was DMD ( r = 0.939; P = 0.06). In Exp. 2, steers readily consumed regrowth hay, averaging 2.73 kg 100 kg −1 BW for the early‐boot cut with a DMD of 670 g kg −1 . Intake declined linearly by postanthesis to 1.57 kg 100 kg −1 BW with a DMD of 517 g kg −1 . Hays of CBS can provide desirable quality for animal production systems if it is cut by the early‐boot stage in the mid‐Atlantic region of the United States. DA - 2011/7// PY - 2011/7// DO - 10.2135/cropsci2010.10.0570 VL - 51 IS - 4 SP - 1840-1849 SN - 0011-183X ER - TY - JOUR TI - Intake and Digestibility among Caucasian Bluestem, Big Bluestem, and Switchgrass Compared with Bermudagrass AU - Burns, J. C. T2 - CROP SCIENCE AB - Warm‐season perennial grasses, mainly bermudagrass [ Cynodon dactylon (L.) Pers.], have been a major source of hay for ruminant systems across the upper southern United States. This study compares the quality of Caucasian bluestem [ Bothriochloa caucasica (Trin.) C.E. Hubbard ‘Caucasian’] (CBS) with ‘Kanlow’ switchgrass ( Panicum virgatum L.) (SG), and big bluestem ( Andropogon gerardi Vitman) (BBS), relative to ‘Coastal’ and ‘Tifton 44’ bermudagrasses, as forages for the upper south. Four intake and digestion experiments, with associated diet characteristics, were conducted using steers. In experiment (Exp.) 1, CBS regrowth (45 d) compared with initial growth had greater ( P = 0.01) daily dry matter (DM) intake (DMI) [2.33 vs. 1.91 kg 100 −1 kg body weight (BW)] and apparent DM digestibility (DMD) (664 vs. 617 g kg −1 ). Initial growth bermudagrass had greater ( P < 0.01) DMI than CBS (2.61 vs. 1.91 kg 100 kg −1 BW) and similar DMD (mean = 619 g kg −1 ). In Exp. 2, initial and regrowth (45 d) CBS, compared with SG, had greater ( P < 0.01) DMI (2.06 vs. 1.23 kg 100 −1 kg BW). In Exp. 3, regrowth CBS and BBS had similar DMI (mean = 1.83 kg 100 −1 kg BW) and DMD (mean = 637 g kg −1 ). In Exp. 4, initial and regrowth (53 d) CBS and regrowth (57 d) BBS had similar DMI (mean = 2.29 kg 100 −1 kg BW), but CBS had greater ( P = 0.01) DMD (602 vs. 566 g kg −1 ). The DMI and DMD of all hays in all experiments ( n = 15) were correlated ( r = 0.66, P < 0.01). In general all hays can contribute to ruminant production systems. DA - 2011/9// PY - 2011/9// DO - 10.2135/cropsci2011.01.0050 VL - 51 IS - 5 SP - 2262-2275 SN - 1435-0653 ER - TY - JOUR TI - Influence of summer cover crops and mycorrhizal fungi on strawberry production in the Southeastern United States AU - Garland, B. C. AU - Schroeder-Moreno, M. S. AU - Fernandez, G. E. AU - Creamer, N. G. T2 - HortScience DA - 2011/// PY - 2011/// VL - 46 IS - 7 SP - 985-992 ER - TY - JOUR TI - Identification of Tobacco Haploids on the Basis of Transgenic Overexpression of PAP1 from Arabidopsis thaliana AU - Lewis, Ramsey S. AU - Rose, Cara T2 - CROP SCIENCE AB - ABSTRACT Haploid plants have utility in plant breeding for several purposes. In tobacco ( Nicotiana tabacum L.) gynogenic haploids can be produced from seed due to parthenogenesis. For practical use, a system is needed to identify infrequent haploid plants at the seed or seedling stage. Interspecific hybridization with N. africana is presently used to isolate gynogenic tobacco haploids because a suitable dominant seedling marker does not currently exist for N. tabacum . Here we investigated the utility of a purple seedling trait conferred by overexpression of the Arabidopsis gene, PAP1 , to identify gynogenic haploids produced from seed. Two tobacco cultivars were crossed as females with a genetic stock homozygous at two 35S : PAP1 transgene loci. Gynogenic haploids were recognized as green seedlings among purple F 1 hybrid seedlings. The average frequency of gynogenic haploidy using this system was f = 0.00027. For comparison, the same cultivars were also hybridized as females with N. africana . The average frequency of gynogenic haploidy using this system was approximately seven times higher than that observed for the 35S : PAP1 system. Having a dominant seedling marker for N. tabacum may permit development of genetic stocks that contribute to an increased predisposition for haploid formation via parthenogenesis. In addition, the 35S : PAP1 genetic marker may have utility for identifying androgenic haploids from seed for the purpose of rapidly generating alloplasmic lines of tobacco. DA - 2011/7// PY - 2011/7// DO - 10.2135/cropsci2010.09.0546 VL - 51 IS - 4 SP - 1491-1497 SN - 1435-0653 ER - TY - JOUR TI - Genetic Diversity and Antimicrobial Resistance of Escherichia coli from Human and Animal Sources Uncovers Multiple Resistances from Human Sources AU - Ibekwe, A. Mark AU - Murinda, Shelton E. AU - Graves, Alexandria K. T2 - PLOS ONE AB - Escherichia coli are widely used as indicators of fecal contamination, and in some cases to identify host sources of fecal contamination in surface water. Prevalence, genetic diversity and antimicrobial susceptibility were determined for 600 generic E. coli isolates obtained from surface water and sediment from creeks and channels along the middle Santa Ana River (MSAR) watershed of southern California, USA, after a 12 month study. Evaluation of E. coli populations along the creeks and channels showed that E. coli were more prevalent in sediment compared to surface water. E. coli populations were not significantly different (P = 0.05) between urban runoff sources and agricultural sources, however, E. coli genotypes determined by pulsed-field gel electrophoresis (PFGE) were less diverse in the agricultural sources than in urban runoff sources. PFGE also showed that E. coli populations in surface water were more diverse than in the sediment, suggesting isolates in sediment may be dominated by clonal populations.Twenty four percent (144 isolates) of the 600 isolates exhibited resistance to more than one antimicrobial agent. Most multiple resistances were associated with inputs from urban runoff and involved the antimicrobials rifampicin, tetracycline, and erythromycin. The occurrence of a greater number of E. coli with multiple antibiotic resistances from urban runoff sources than agricultural sources in this watershed provides useful evidence in planning strategies for water quality management and public health protection. DA - 2011/6/8/ PY - 2011/6/8/ DO - 10.1371/journal.pone.0020819 VL - 6 IS - 6 SP - SN - 1932-6203 ER - TY - JOUR TI - General Resistance in Maize to Southern Rust (Puccinia polysora Underw.) AU - Brewbaker, James L. AU - Kim, Soon Kwon AU - So, Yoon Sup AU - Logrono, Manuel AU - Moon, Hyeon Gui AU - Ming, Reiguang AU - Lu, Xiao Wu AU - Josue, Aleksander D. T2 - CROP SCIENCE AB - ABSTRACT Southern corn rust (Puccinia polysora Underw.) is a major tropical disease that can lead to severe yield losses in the tropics. Occasionally it becomes of concern in temperate regions, as in 2010. We summarize 45 yr of research on the occurrence, genetic basis, and breeding of general resistance. Trials were conducted in Colombia, Hawaii, Nigeria, the Philippines, Texas, and Thailand. Temperate maize proved uniformly susceptible. No racially specific monogenes were effective. Resistance varied continuously among tropical inbreds and many of these showed stable intermediate tolerance. Two diallel populations revealed high correlations of inbred values with hybrid array means and slight heterosis for resistance. Narrow‐sense heritabilities were 51% and 66%, and mean square ratios for general to specific combining ability (GCA:SCA) were 7.8 and 10.7 to 1. Generation mean analyses were performed on six sets of families. Mean and additive effects were significant across families, while significant nonadditive effects were rare. Heritability values ranged from 19% to 49%. A set of recombinant lines segregated a primary susceptibility locus on chromosome 6. Studies of 137 near‐isogenic inbred lines (NILs) of resistant tropical inbred Hi27 revealed a dominant susceptibility quantitative trait locus (QTL) in the NIL for dwarf‐1 locus, but linkage could not be confirmed. Premature senescence was associated with rust infections in many NILs, emphasizing the ubiquity of modifying genes. No correlation existed between resistance to southern and common rusts. Resistant tropical inbreds and populations were bred to serve as sources for future improvement. DA - 2011/7// PY - 2011/7// DO - 10.2135/cropsci2010.06.0327 VL - 51 IS - 4 SP - 1393-1409 SN - 1435-0653 ER - TY - JOUR TI - Exploring fecal indicator bacteria in a constructed stormwater wetland AU - Hathaway, J. M. AU - Hunt, W. F. AU - Graves, A. K. AU - Bass, K. L. AU - Caldwell, A. T2 - WATER SCIENCE AND TECHNOLOGY AB - Microbial pollution in surface waters is a concern throughout the world, with both public health and economic implications. One contributing source to such pollution is stormwater runoff, often treated using various types of stormwater control measures. However, relatively little is known regarding microbe sequestration in constructed stormwater wetlands (CSWs), one type of commonly installed stormwater control measure. In this study, indicator bacteria concentrations in both the water and sediment of a CSW were evaluated at multiple locations. Results suggested that fecal coliform concentrations in stormwater runoff decrease through the system, with relatively consistent concentrations noted throughout the second half of the wetland. This potentially indicates a baseline concentration of fecal coliform is present due to internal processes such as animal activity and microbial persistence. However, wetland sediments showed little E. coli present during most sampling events, with minimal patterns existing with respect to sediment sampling location. CSW designs should promote optimization of hydraulic retention time and minimization of stormwater velocities to promote sedimentation and degradation of microbes by way of wetland treatment functions. DA - 2011/// PY - 2011/// DO - 10.2166/wst.2011.539 VL - 63 IS - 11 SP - 2707-2712 SN - 1996-9732 KW - fecal coliform KW - microbe KW - sediment KW - stormwater KW - wetland ER - TY - JOUR TI - Comparison of Conventional, Modified Single Seed Descent, and Doubled Haploid Breeding Methods for Maize Inbred Line Development Using Germplasm Enhancement of Maize Breeding Crosses AU - Jumbo, McDonald AU - Weldekidan, Teclemariam AU - Holland, James B. AU - Hawk, James A. T2 - CROP SCIENCE AB - ABSTRACT Breeding crosses from the Germplasm Enhancement of Maize (GEM) project between exotic accessions and elite Corn Belt Dent inbreds provide a unique opportunity for broadening the genetic base of the U.S. maize ( Zea mays L.) crop by incorporating favorable exotic alleles in elite genetic backgrounds. Genetic gains in the GEM program could be enhanced by identifying more efficient breeding procedures for this purpose. We compared four breeding methods, conventional Germplasm Enhancement of Maize (CG), conventional mass (CM), modified single seed descent (MSSD), and doubled haploid (DH) methods, for their relative capacity to produce superior maize inbred lines and hybrids from three GEM breeding crosses: (ANTIG01 × N16) × DE4, (AR16035 × S02) × S09, and (DKXL212 × S09) × S43b. Testcross evaluations of 50 selected lines from each combination of cross and breeding method were conducted across multiple environments, generally revealing no differences among breeding methods. The MSSD and CM methods had higher proportions of the top 10 lines for grain yield and yield:moisture ratio in the second year testcross reevaluations of about the top 28% of lines. Hybrids from MSSD lines tended to have higher grain moisture, but MSSD hybrids with high yield:moisture ratio could still be identified. The MSSD method may be an effective and efficient alternative to both pedigree and DH methods for developing high performing lines from the GEM breeding crosses as it requires relatively fewer resources. DA - 2011/7// PY - 2011/7// DO - 10.2135/cropsci2010.10.0594 VL - 51 IS - 4 SP - 1534-1543 SN - 0011-183X UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79959605955&partnerID=MN8TOARS ER - TY - JOUR TI - Bushkiller (Cayratia japonica) Response to Selected Herbicides AU - West, Amanda M. AU - Richardson, Robert J. AU - Gardner, Andrew P. AU - Hoyle, Steve T. T2 - INVASIVE PLANT SCIENCE AND MANAGEMENT AB - Abstract Bushkiller, an aggressive perennial vine native to Southeast Asia, has invaded several sites in Alabama, North Carolina, Texas, Louisiana, and Mississippi. Bushkiller has only recently been discovered in North Carolina. The potential economic and environmental consequences associated with established exotic invasive perennial vines and the lack of published control measures for bushkiller prompted research to be conducted at North Carolina State University that may be used in an early-detection rapid-response program. Field and greenhouse studies were conducted to determine bushkiller response to selected foliar-applied herbicides. Field study 1 evaluated efficacy of glyphosate, triclopyr, triclopyr plus 2,4-D, triclopyr plus aminopyralid, and triclopyr plus glyphosate applied postemergence to bushkiller. No control was evident from any treatment at 10 mo after application. In a separate experiment, aminocyclopyrachlor, imazapyr, metsulfuron, sulfometuron, and sulfometuron plus metsulfuron were applied postemergence to bushkiller. Control with aminocyclopyrachlor, imazapyr, sulfometuron, and sulfometuron plus metsulfuron was 88 to 99% at 10 mo after application. Each treatment was also applied to bushkiller in a greenhouse trial. Aminocyclopyrachlor and triclopyr-containing treatments generally resulted in the greatest control, lowest dry weights, and shortest vine lengths among the treatments. These results indicate that several herbicides may be employed initially in an early-detection, rapid-response program for bushkiller. Additional research is needed to determine how effective these herbicides would be in multiple-season treatments that may be required at well established bushkiller infestation sites. DA - 2011/// PY - 2011/// DO - 10.1614/ipsm-d-10-00038.1 VL - 4 IS - 1 SP - 73-77 SN - 1939-747X KW - Herbicide KW - perennial vines ER - TY - JOUR TI - Weed Management with Glyphosate- and Glufosinate-Based Systems in PHY 485 WRF Cotton AU - Whitaker, Jared R. AU - York, Alan C. AU - Jordan, David L. AU - Culpepper, A. Stanley T2 - WEED TECHNOLOGY AB - Glyphosate-resistant (GR) Palmer amaranth has become a serious pest in parts of the Cotton Belt. Some GR cotton cultivars also contain the WideStrike™ insect resistance trait, which confers tolerance to glufosinate. Use of glufosinate-based management systems in such cultivars could be an option for managing GR Palmer amaranth. The objective of this study was to evaluate crop tolerance and weed control with glyphosate-based and glufosinate-based systems in PHY 485 WRF cotton. The North Carolina field experiment compared glyphosate and glufosinate alone and in mixtures applied twice before four- to six-leaf cotton. Additional treatments included glyphosate and glufosinate mixed with S -metolachlor or pyrithiobac applied to one- to two-leaf cotton followed by glyphosate or glufosinate alone on four- to six-leaf cotton. All treatments received a residual lay-by application. Excellent weed control was observed from all treatments on most weed species. Glyphosate was more effective than glufosinate on glyphosate-susceptible (GS) Palmer amaranth and annual grasses, while glufosinate was more effective on GR Palmer amaranth. Annual grass and GS Palmer amaranth control by glyphosate plus glufosinate was often less than control by glyphosate alone but similar to or greater than control by glufosinate alone, while mixtures were more effective than either herbicide alone on GR Palmer amaranth. Glufosinate caused minor and transient injury to the crop, but no differences in cotton yield or fiber quality were noted. This research demonstrates glufosinate can be applied early in the season to PHY 485 WRF cotton without concern for significant adverse effects on the crop. Although glufosinate is often less effective than glyphosate on GS Palmer amaranth, GR Palmer amaranth can be controlled with well-timed applications of glufosinate. Use of glufosinate in cultivars with the WideStrike trait could fill a significant void in current weed management programs for GR Palmer amaranth in cotton. DA - 2011/// PY - 2011/// DO - 10.1614/wt-d-10-00008.1 VL - 25 IS - 2 SP - 183-191 SN - 1550-2740 KW - Carpetweed KW - common lambsquarters KW - common ragweed KW - crop tolerance KW - crowfootgrass KW - entireleaf morningglory KW - fall panicum KW - glyphosate-resistant weeds KW - goosegrass KW - herbicide-resistant cotton KW - large crabgrass KW - Palmer amaranth KW - pitted morningglory KW - pyrithiobac KW - redroot pigweed KW - S-metolachlor KW - sicklepod KW - tall morningglory KW - Widestrike (TM) cotton ER - TY - JOUR TI - The Effects of Weak Genetic Perturbations on the Transcriptome of the Wing Imaginal Disc and Its Association With Wing Shape in Drosophila melanogaster AU - Dworkin, Ian AU - Anderson, Julie A. AU - Idaghdour, Youssef AU - Parker, Erin Kennerly AU - Stone, Eric A. AU - Gibson, Greg T2 - GENETICS AB - Abstract A major objective of genomics is to elucidate the mapping between genotypic and phenotypic space as a step toward understanding how small changes in gene function can lead to elaborate phenotypic changes. One approach that has been utilized is to examine overall patterns of covariation between phenotypic variables of interest, such as morphology, physiology, and behavior, and underlying aspects of gene activity, in particular transcript abundance on a genome-wide scale. Numerous studies have demonstrated that such patterns of covariation occur, although these are often between samples with large numbers of unknown genetic differences (different strains or even species) or perturbations of large effect (sexual dimorphism or strong loss-of-function mutations) that may represent physiological changes outside of the normal experiences of the organism. We used weak mutational perturbations in genes affecting wing development in Drosophila melanogaster that influence wing shape relative to a co-isogenic wild type. We profiled transcription of 1150 genes expressed during wing development in 27 heterozygous mutants, as well as their co-isogenic wild type and one additional wild-type strain. Despite finding clear evidence of expression differences between mutants and wild type, transcriptional profiles did not covary strongly with shape, suggesting that information from transcriptional profiling may not generally be predictive of final phenotype. We discuss these results in the light of possible attractor states of gene expression and how this would affect interpretation of covariation between transcriptional profiles and other phenotypes. DA - 2011/4// PY - 2011/4// DO - 10.1534/genetics.110.125922 VL - 187 IS - 4 SP - 1171-U314 SN - 1943-2631 ER - TY - JOUR TI - Starch Self-Processing in Transgenic Sweet Potato Roots Expressing a Hyperthermophilic alpha-Amylase AU - Santa-Maria, Monica C. AU - Yencho, Craig G. AU - Haigler, Candace H. AU - Thompson, William F. AU - Kelly, Robert M. AU - Sosinski, Bryon T2 - BIOTECHNOLOGY PROGRESS AB - Abstract Sweet potato is a major crop in the southeastern United States, which requires few inputs and grows well on marginal land. It accumulates large quantities of starch in the storage roots and has been shown to give comparable or superior ethanol yields to corn per cultivated acre in the southeast. Starch conversion to fermentable sugars (i.e., for ethanol production) is carried out at high temperatures and requires the action of thermostable and thermoactive amylolytic enzymes. These enzymes are added to the starch mixture impacting overall process economics. To address this shortcoming, the gene encoding a hyperthermophilic α‐amylase from Thermotoga maritima was cloned and expressed in transgenic sweet potato, generated by Agrobacterium tumefaciens‐mediated transformation, to create a plant with the ability to self‐process starch. No significant enzyme activity could be detected below 40°C, but starch in the transgenic sweet potato storage roots was readily hydrolyzed at 80°C. The transgene did not affect normal storage root formation. The results presented here demonstrate that engineering plants with hyperthermophilic glycoside hydrolases can facilitate cost effective starch conversion to fermentable sugars. Furthermore, the use of sweet potato as an alternative near‐term energy crop should be considered. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011 DA - 2011/// PY - 2011/// DO - 10.1002/btpr.573 VL - 27 IS - 2 SP - 351-359 SN - 1520-6033 KW - hyperthermophilic enzymes KW - starch conversion KW - transgenic plants KW - sweet potato KW - biofuels ER - TY - JOUR TI - Microbial and soil properties in bentgrass putting greens: Impacts of nitrogen fertilization rates AU - Liu, Yueyan AU - Dell, Emily AU - Yao, Huaiying AU - Rufty, Thomas AU - Shi, Wei T2 - GEODERMA AB - Nitrogen fertilization is important for maintaining the quality of golf course putting greens, but causes environmental concerns and affects soil organic matter buildup. Belowground biology and processes are vital to address both environmental and organic buildup issues. We examined microbial and soil properties in sand-based bentgrass putting greens that had been unfertilized or fertilized at the rates of 195, 244, and 305 kg N ha−1 yr−1 for over one year after turf establishment. Nitrogen fertilization increased soil organic C by ~ 10% and slightly modified microbial community as revealed by denaturing gradient gel electrophoresis, but had no effects on microbial biomass or C and N mineralization. We observed that changes in soil pH and enzyme activities were the functions of fertilization rates. Soil pH was reduced by ~ 0.3 to 0.8 units as fertilization rates increased. The activities of soil enzymes (β-glucosidase, N-acetyl-β-glucosaminidase, chitinase, and cellulase) were enhanced by fertilization at 195 or 244 kg N ha−1 yr−1, but was equivalent to or even lower than those in the unfertilized control when fertilization rate reached 305 kg N ha−1 yr−1. Results indicated that the activity of soil enzymes could be used as an important metric to diagnose the impacts of fertilization rates on soil. Fertilization rate at approximately 200 kg N ha−1 yr−1 appeared to be appropriate for managing putting greens. DA - 2011/4/15/ PY - 2011/4/15/ DO - 10.1016/j.geoderma.2011.02.009 VL - 162 IS - 1-2 SP - 215-221 SN - 1872-6259 KW - Soil enzyme activity KW - Microbial biomass KW - C and N mineralization KW - N fertilization KW - Turfgrass ER - TY - JOUR TI - Influence of field margin type on weed species richness and abundance in conventional crop fields AU - Reberg-Horton, S. C. AU - Mueller, J. P. AU - Mellage, S. J. AU - Creamer, N. G. AU - Brownie, C. AU - Bell, M. AU - Burton, M. G. T2 - RENEWABLE AGRICULTURE AND FOOD SYSTEMS AB - Abstract Natural vegetation occurring on farms in field margins, fallow fields, ditch systems and neighboring forests, provides increased biodiversity, structural diversity, habitat for wildlife and beneficial insects, and can act as a protective buffer against agrochemical drift. Nevertheless, farmers frequently view these areas as non-productive and as potential sources of weeds, insect pests and diseases. Weed species richness and abundance were examined in crop fields in 2002–2003 at the Center for Environmental Farming Systems near Goldsboro, NC to determine if crop field weed infestation was associated with field margin management (managed versus unmanaged). Weed species abundance and richness were measured over two growing seasons on four occasions in crop fields along permanent transects that extended from the field edge toward the center of the field. The presence/absence of data for all plant species in the field margin was also recorded. For both margin types, managed and unmanaged, more weeds were found near the field edge than in the center of the field. Weed species richness was slightly higher in cropland bordering managed margins than in cropland along unmanaged margins. Several significant interactions led to an examination of nine dominant weed species in each field margin type and their distribution in crop fields. When all sampling dates were pooled, only 42 (40%) of 105 species identified in the field margins were observed in the crop field. Managed margins had lower species richness than unmanaged field margins—less than half the mean number of species (15 versus 6 species, respectively). Contingency table analysis did not reveal any association between plant species occurring in the margin and those found in the crop field. Furthermore, margin type and weed presence in the field margin were not effective predictors of weed occurrence in the crop field as determined by logistic regression. DA - 2011/6// PY - 2011/6// DO - 10.1017/s1742170510000451 VL - 26 IS - 2 SP - 127-136 SN - 1742-1705 KW - field margin KW - weed populations KW - crop edges KW - farm natural areas ER - TY - JOUR TI - Effect of lead (Pb) on the systemic movement of RNA viruses in tobacco (Nicotiana tabacum var. Turkish) AU - Alkhatib, Rami AU - Creamer, Rebecca AU - Lartey, Robert T. AU - Ghoshroy, Soumitra T2 - PLANT CELL REPORTS DA - 2011/8// PY - 2011/8// DO - 10.1007/s00299-011-1051-9 VL - 30 IS - 8 SP - 1427-1434 SN - 0721-7714 KW - Callose KW - Inoculation KW - Plasmodesmata KW - RNA viruses KW - Systemic movement ER - TY - JOUR TI - Development of a PCR assay and marker-assisted transfer of leaf rust resistance gene Lr58 into adapted winter wheats AU - Kuraparthy, Vasu AU - Sood, Shilpa AU - Guedira, Gina-Brown AU - Gill, Bikram S. T2 - EUPHYTICA AB - Leaf rust resistance gene Lr58 derived from Aegilops triuncialis L. was transferred to the hard red winter wheat (HRWW) cultivars Jagger and Overley by standard backcrossing and marker-assisted selection (MAS). A co-dominant PCR-based sequence tagged site (STS) marker was developed based on the sequence information of the RFLP marker (XksuH16) diagnostically detecting the alien segment in T2BS·2BL-2tL(0.95). STS marker Xncw-Lr58-1 was used to select backcross F1 plants with rust resistance. The co-dominant marker polymorphism detected by primer pair NCW-Lr58-1 efficiently identified the homozygous BC3F2 plants with rust resistance gene Lr58. The STS marker Xncw-Lr58-1 showed consistent diagnostic polymorphism between the resistant source and the wheat cultivars selected by the US Wheat Coordinated Agricultural Project. The utility and compatibility of the STS marker in MAS programs involving robust genotyping platforms was demonstrated in both agarose-based and capillary-based platforms. Screening backcross derivatives carrying Lr58 with various rust races at seedling stage suggested the transferred rust resistance in adapted winter wheats is stable in both cultivar backgrounds. Lr58 in adapted winter wheat backgrounds could be used in combination with other resistance genes in wheat rust resistance breeding. DA - 2011/7// PY - 2011/7// DO - 10.1007/s10681-011-0383-4 VL - 180 IS - 2 SP - 227-234 SN - 1573-5060 KW - Wheat KW - Rust resistance KW - Marker-assisted selection KW - Mapping ER - TY - JOUR TI - Surface shading effects on soil C loss in a temperate muck soil AU - Taggart, Matthew J. AU - Heitman, Joshua L. AU - Vepraskas, Michael J. AU - Burchell, Michael R. T2 - Geoderma AB - Histosols are a huge reservoir for C, covering < 1% of the world's land surface but storing up to 12% of total soil C. Thorough comprehension of factors controlling the rate of soil C loss from Histosols is critical for proper management of these C sinks. Two experiments evaluated how formerly cultivated, warm-climate Histosols undergoing wetland restoration respond to decreases in soil temperatures via vegetative shading, under different water table conditions. We compared temperature and soil CO2 efflux differences from intact soil cores under three levels of light reduction in a greenhouse: 0%, 70%, and 90%. Soil in full sun was consistently warmer and showed higher efflux rates than 70% and 90% shade treatments: 4.132, 3.438, and 2.054 μmol CO2 m−2 s−1, respectively. Shade treatments reached peak efflux rates at similar water potential, −2 to − 4 kPa. A field experiment subjected in-situ soil to full sun, 70% light reduction, and light reduction from naturally occurring herbaceous vegetation. Shade treatment effects on soil temperature and C mineralization were evident throughout the growing season. Vegetative shade effects on soil temperature were greatest in August and September when soil under vegetation was 5–11 °C cooler than unshaded soil. Soil CO2 efflux was correlated strongly with soil temperature; daily efflux rates were consistently highest from unshaded soil. Efflux across treatments showed a strong seasonal correlation to soil moisture, increasing as soil dried in response to water table decline. Soil water potential was unaffected by shade treatment, suggesting temperature effects were solely responsible for efflux differences between treatments. All results confirm that surface shading has a strong influence on soil temperatures and C mineralization rates. Management to enhance vegetative shading in wetland restoration projects may be an effective strategy for slowing soil C losses and promoting soil C sequestration when O2 is not limiting. DA - 2011/7// PY - 2011/7// DO - 10.1016/j.geoderma.2011.04.020 VL - 163 IS - 3-4 SP - 238-246 J2 - Geoderma LA - en OP - SN - 0016-7061 UR - http://dx.doi.org/10.1016/j.geoderma.2011.04.020 DB - Crossref KW - Histosols KW - Wetland restoration KW - CO2 efflux KW - Mineralization KW - Soil temperature KW - Shading ER - TY - JOUR TI - Distribution of ten antibiotic resistance genes in E. coli isolates from swine manure, lagoon effluent and soil collected from a lagoon waste application field AU - Graves, A. K. AU - Liwimbi, L. AU - Israel, D. W. AU - Heugten, E. AU - Robinson, B. AU - Cahoon, C. W. AU - Lubbers, J. F. T2 - FOLIA MICROBIOLOGICA DA - 2011/3// PY - 2011/3// DO - 10.1007/s12223-011-0019-z VL - 56 IS - 2 SP - 131-137 SN - 0015-5632 ER - TY - JOUR TI - Cumulative Soil Water Evaporation as a Function of Depth and Time AU - Xiao, X. AU - Horton, R. AU - Sauer, T. J. AU - Heitman, J. L. AU - Ren, T. T2 - VADOSE ZONE JOURNAL AB - Soil water evaporation is an important component of the surface water balance and the surface energy balance. Accurate and dynamic measurements of soil water evaporation enhance the understanding of water and energy partitioning at the land–atmosphere interface. The objective of this study was to measure the cumulative soil water evaporation with time and depth in a bare field. Cumulative water evaporation at the soil surface was measured by the Bowen ratio method. Subsurface cumulative soil water evaporation was determined with the heat pulse method at fine‐scale depth increments. Following rainfall, the subsurface cumulative evaporation curves followed a pattern similar to the surface cumulative evaporation curve, with approximately a 2‐d lag before evaporation was indicated at the 3‐ and 9‐mm soil depths, and several more days' delay in deeper soil layers. For a 21‐d period in 2007, the cumulative evaporation totals at soil depths of 0, 3, 9, 15, and 21 mm were 60, 44, 29, 13, and 8 mm, respectively. For a 16‐d period in 2008, the cumulative evaporation totals at soil depths of 0, 3, 9, 15, and 21 mm were 32, 25, 16, 10, and 5 mm, respectively. Cumulative evaporation results from the Bowen ratio and heat pulse methods indicated a consistent dynamic pattern for surface and subsurface water evaporation with both time and depth. These findings suggest that heat pulse sensors can accurately measure subsurface soil water evaporation during several wetting–drying cycles. DA - 2011/8// PY - 2011/8// DO - 10.2136/vzj2010.0070 VL - 10 IS - 3 SP - 1016-1022 SN - 1539-1663 ER - TY - JOUR TI - Challenges in breeding for yield increase for drought AU - Sinclair, Thomas R. T2 - TRENDS IN PLANT SCIENCE AB - Crop genetic improvement for environmental stress at the molecular and physiological level is very complex and challenging. Unlike the example of the current major commercial transgenic crops for which biotic stress tolerance is based on chemicals alien to plants, the complex, redundant and homeostatic molecular and physiological systems existing in plants must be altered for drought tolerance improvement. Sophisticated tools must be developed to monitor phenotype expression at the crop level to characterize variation among genotypes across a range of environments. Once stress-tolerant cultivars are developed, regional probability distributions describing yield response across years will be necessary. This information can then aid in identifying environmental conditions for positive and negative responses to genetic modification to guide farmer selection of stress-tolerant cultivars. DA - 2011/6// PY - 2011/6// DO - 10.1016/j.tplants.2011.02.008 VL - 16 IS - 6 SP - 289-293 SN - 1878-4372 ER - TY - JOUR TI - Association genetics of carbon isotope discrimination, height and foliar nitrogen in a natural population of Pinus taeda L AU - Cumbie, W. P. AU - Eckert, A. AU - Wegrzyn, J. AU - Whetten, R. AU - Neale, D. AU - Goldfarb, B. T2 - HEREDITY AB - Loblolly pine, Pinus taeda L., is one of the most widely planted, commercially and ecologically important tree species in North America. We took an association genetics approach, using an unimproved population of 380 clonally replicated unrelated trees, to test 3,938 single nucleotide polymorphisms (SNPs) in as many genes for association with phenotypic variation in carbon isotope discrimination, foliar nitrogen concentration and total tree height after two growing seasons. Best linear unbiased prediction (BLUP) was used with a spatial adjustment to remove environmental variation from phenotypic data derived from a common garden experiment. After correction for multiple testing, a total of 14 SNPs were associated with the traits of carbon isotope discrimination (n = 7), height (n = 1) and foliar nitrogen concentration (n = 6) using 380 clones. Tails of the population phenotypic distribution were compared for allele frequency differences, revealing 10 SNPs with allele frequency in at least one tail significantly different from the overall population. Eight associated SNPs were in sequences similar to known genes, such as an AP2 transcription factor related to carbon isotope discrimination and glutamate decarboxylase associated with foliar nitrogen concentration, and others were from unknown genes without homologs in Arabidopsis. DA - 2011/8// PY - 2011/8// DO - 10.1038/hdy.2010.168 VL - 107 IS - 2 SP - 105-114 SN - 0018-067X KW - water use efficiency KW - forest tree KW - population genetics KW - loblolly pine ER - TY - JOUR TI - A novel genetic framework for studying response to artificial selection AU - Wisser, Randall J. AU - Balint-Kurti, Peter J. AU - Holland, James B. T2 - PLANT GENETIC RESOURCES-CHARACTERIZATION AND UTILIZATION AB - Response to selection is fundamental to plant breeding. To gain insight into the genetic basis of response to selection, we propose a new experimental genetic framework allowing for the identification of trait-specific genomic loci underlying population improvement and the characterization of allelic frequency responses at those loci. This is achieved by employing a sampling scheme for recurrently selected populations that allows for the simultaneous application of genetic association mapping and analysis of allelic frequency change across generations of selection. The combined method unites advantages of the two approaches, permitting the estimation of trait-specific allelic effects by association mapping and the detection of rare favourable alleles by their significant enrichment over generations of selection. Our aim is to develop a framework applicable for many crop species in order to gain a broader and deeper understanding of the genetic architecture of response to artificial selection. DA - 2011/7// PY - 2011/7// DO - 10.1017/s1479262111000359 VL - 9 IS - 2 SP - 281-283 SN - 1479-2621 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79960130677&partnerID=MN8TOARS KW - adaptation KW - association mapping KW - plant breeding, quantitative trait KW - selection ER - TY - JOUR TI - Seasonal variations of soil microbial biomass and activity in warm- and cool-season turfgrass systems AU - Yao, Huaiying AU - Bowman, Daniel AU - Shi, Wei T2 - SOIL BIOLOGY & BIOCHEMISTRY AB - Plant growth can be an important factor regulating seasonal variations of soil microbial biomass and activity. We investigated soil microbial biomass, microbial respiration, net N mineralization, and soil enzyme activity in turfgrass systems of three cool-season species (tall fescue, Festuca arundinacea Schreb., Kentucky bluegrass, Poa pratensis L., and creeping bentgrass, Agrostis palustris L.) and three warm-season species (centipedegrass, Eremochloa ophiuroides (Munro.) Hack, zoysiagrass, Zoysia japonica Steud, and bermudagrass, Cynodon dactylon (L.) Pers.). Microbial biomass and respiration were higher in warm- than the cool-season turfgrass systems, but net N mineralization was generally lower in warm-season turfgrass systems. Soil microbial biomass C and N varied seasonally, being lower in September and higher in May and December, independent of turfgrass physiological types. Seasonal variations in microbial respiration, net N mineralization, and cellulase activity were also similar between warm- and cool-season turfgrass systems. The lower microbial biomass and activity in September were associated with lower soil available N, possibly caused by turfgrass competition for this resource. Microbial biomass and activity (i.e., microbial respiration and net N mineralization determined in a laboratory incubation experiment) increased in soil samples collected during late fall and winter when turfgrasses grew slowly and their competition for soil N was weak. These results suggest that N availability rather than climate is the primary determinant of seasonal dynamics of soil microbial biomass and activity in turfgrass systems, located in the humid and warm region. DA - 2011/7// PY - 2011/7// DO - 10.1016/j.soilbio.2011.03.031 VL - 43 IS - 7 SP - 1536-1543 SN - 0038-0717 KW - Microbial biomass KW - Microbial respiration KW - N mineralization KW - Soil enzyme activity KW - Turfgrass ER - TY - JOUR TI - Predicting Soil Phosphorus Fertilizer Rate Using Hierarchical Segmented Regression Models AU - Shuai, Xiufu AU - Yost, Russell S. AU - Smyth, T. Jot T2 - SOIL SCIENCE AB - Predicting soil phosphorus (P) needs and P fertilizer requirements is important for plant nutrition and reducing environmental risk. The P requirement (PR) can be calculated from three components: the current status of soil P (P0), soil P buffer coefficient (PBC), and the soil P critical level (PCL). The PBC and PCL can be predicted from soil clay content using linear-plateau models. The PR, PBC, and PCL form a hierarchical model because PR depends on PBC and PCL, which, in turn, depend on soil clay content. The objective of this study is to estimate the parameters in this hierarchical model to ensure reasonable performance and behavior of PR in a large range of soil clay contents. Results showed that the linear-plateau model described the change of PBC with soil clay content in the range of 39 to 760 g kg−1. This model also described the change of PCL with soil clay content in the range of 80 to 760 g kg−1 for six crops, including cotton, cowpea, maize, peanut, soybean, and wheat. The obtained PR showed irregular behavior of PR within soil clay content range from 288 to 357 g kg−1 when PBC and PCL were independently predicted from soil clay. When the join points in the linear-plateau models of PBC and PCL were set to be equal, the irregular change of PR with soil clay content disappeared. The hierarchically modeled system predicts a decrease in PR with increasing current status of soil P and a curve-plateau trend with soil clay content. DA - 2011/6// PY - 2011/6// DO - 10.1097/ss.0b013e318219db24 VL - 176 IS - 6 SP - 303-306 SN - 0038-075X KW - Phosphorus model KW - phosphorus fertilization KW - PDSS KW - NuMaSS ER - TY - JOUR TI - Inositol Metabolism in Developing Seed of Low and Normal Phytic Acid Soybean Lines AU - Israel, Daniel W. AU - Taliercio, Earl AU - Kwanyuen, Prachuab AU - Burton, Joseph W. AU - Dean, Lisa T2 - CROP SCIENCE AB - While inositol has key roles in phytic acid and raffinosaccharide synthesis, its concentration in developing seed of low phytic acid soybean [ Glycine max (L.) Merr.] lines derived from CX1834 (Wilcox et al., 2000) has not been compared to that of normal lines. Concentrations of metabolites in the phytic acid and raffinosaccharide biosynthesis have been measured in mature seed of CX1834‐derived lines but not throughout seed development. Our objective was to compare concentrations of inositol and metabolites associated with phytic acid and raffinosaccharide synthesis in developing seed of CX1834‐derived and normal lines. Plants were cultured with complete nutrient solutions in growth chambers with 650 to 700 μmol m −2 s −1 of photosynthetically active radiation and a 26/22°C day/night temperature. Seed inositol concentrations were high (60 to 90 mmol kg −1 seed dry wt.) at 20 d after flowering (DAF) and decreased 95% by maturity in both normal and low phytic acid lines. In two of three experiments, low phytic acid lines had significantly ( p ≤ 0.05) greater seed inositol concentrations than normal lines at the first two sampling dates, but differences at maturity were not significant. Seeds of low phytic acid and normal lines had statistically similar concentrations ( p > 0.05) of partially phosphorylated inositol intermediate (inositol triphosphate [IP3]), stachyose, raffinose, and phytase activity throughout development. These results corroborate previous studies that ruled out defects in genes coding myo ‐inositol‐1‐P synthase, inositol kinases, and phytase as the basis for the low seed phytic acid trait in CX1834‐derived lines. DA - 2011/// PY - 2011/// DO - 10.2135/cropsci2010.03.0123 VL - 51 IS - 1 SP - 282-289 SN - 1435-0653 ER - TY - JOUR TI - Runoff water quality and vegetative establishment for groundcovers on steep slopes AU - Babcock, D. L. AU - McLaughlin, R. A. T2 - JOURNAL OF SOIL AND WATER CONSERVATION AB - Construction sites can be a major source of sediment, a common pollutant in surface waters, because steep slopes are often bare during active construction. The use of mulch and polymers has been found to reduce erosion rates and improve runoff water quality on construction sites. Different erosion control methods on steep slopes (2:1) consisting of straw, straw plus 37 kg ha−1 (33 lb ac−1) linear anionic polyacrylamide (straw + PAM), and excelsior blankets were evaluated based on runoff water quality, vegetative establishment, or both at six construction sites. Plots (3 to 9 m [10 to 30 ft] wide by 9 m [29.5 ft] long) were established on cut slopes. Runoff was collected at four of six sites by installing plastic barriers to direct a portion of runoff into containers, later analyzed for turbidity and total suspended solids (TSS) in the laboratory. Large differences in water quality were often not statistically significant for individual storms due to high variability. However, when data were averaged across all storm events, the straw + PAM treatment reduced mean runoff turbidity at three of four sites and mean TSS at two of the four sites compared to straw alone. Maximum reductions in turbidity and TSS were 81% and 56%, respectively. Runoff from the excelsior plots had significantly lower turbidity and TSS than straw plots in one of three sites. Compared to straw + PAM, excelsior had significantly higher turbidity at two of three sites and higher TSS at one of three sites. All differences among treatments for individual storm events occurred within the first three events. Vegetative cover was determined in the field, and aboveground vegetation was harvested to determine biomass production. Neither vegetative cover nor biomass were affected by treatment, and average cover was 60% or less for five of the six sites. Rainfall patterns were largely responsible for vegetative growth, with heavier rainfall soon after seeding tending to reduce cover. DA - 2011/// PY - 2011/// DO - 10.2489/jswc.66.2.132 VL - 66 IS - 2 SP - 132-141 SN - 1941-3300 KW - erosion KW - excelsior KW - ground cover KW - polyacrylamide KW - straw ER - TY - JOUR TI - Predictive Ability Assessment of Linear Mixed Models in Multienvironment Trials in Corn AU - So, Yoon-Sup AU - Edwards, Jode T2 - CROP SCIENCE AB - ABSTRACT Prediction of future performance of cultivars is an important objective of multienvironment trials (MET). A series of linear mixed models with varying degrees of heterogeneous genotypic variance, correlation, and error variance structure were compared for their ability to predict performance in an untested environment in 51 data sets from the Iowa Crop Performance Test for corn ( Zea mays L.). In most cases there was no substantial improvement in predictions among models that included heterogeneity of genotypic variance–covariance components, but the best prediction model included heterogeneous environment‐specific error variances in 63% of data sets analyzed. The largest differences in predictive ability among models appeared to be due to poor estimation of genotypic covariance components in data sets with few common hybrids across 2 yr in a data set. Simulation confirmed the observation from cross validation. Our results suggested that predictions were not improved by modeling heterogeneous genotypic covariance components because of the small number of common hybrids across years. Inclusion of heterogeneous error variances did lead to slight improvements in predictions. DA - 2011/3// PY - 2011/3// DO - 10.2135/cropsci2010.06.0338 VL - 51 IS - 2 SP - 542-552 SN - 1435-0653 ER - TY - JOUR TI - Marker Development and Quantitative Trait Loci in a Fall-Sown Oat Recombinant Inbred Population AU - Maloney, P. V. AU - Lyerly, J. H. AU - Wooten, D. R. AU - Anderson, J. M. AU - Livingston, D. P., III AU - Brown-Guedira, G. AU - Marshall, D. AU - Murphy, J. P. T2 - CROP SCIENCE AB - ABSTRACT Marker‐assisted selection for improved winter survival in oat ( Avena sativa L.) is difficult because the number of simple sequence repeat (SSR) markers available in this species is limited. The objectives of this research were to increase the number of SSR markers on the ‘Fulghum’ × ‘Norline’ recombinant inbred population genetic map and to scan for quantitative trait loci (QTL) associated with winter field survival, crown freezing tolerance, vernalization response, and heading date. New SSR markers were developed from ‘Kanota’ and ‘Ogle’ genomic DNA libraries enriched for eight microsatellite motifs. New primers were evaluated for amplification, reproducibility, and polymorphism in 11 oat lines. Simple sequence repeat markers showing high‐quality polymorphism between Fulghum and Norline were subsequently examined in 128 recombinant inbred lines. Sixty‐five new SSR, four single nucleotide polymorphism (SNP), and one cleaved amplified polymorphic sequence (CAPS) markers were added to the Fulghum × Norline linkage map. This brought the total number of markers mapped on the population to 101. Phenotypic data for winter hardiness component traits in the population were obtained in previous field and controlled chamber experiments. All previously mapped markers and new SSR markers were evaluated and QTL identified. Marker loci on linkage group FN1_3_38 accounted for multiple QTL associated with winter hardiness component traits. The addition of new SSR markers to the Fulghum × Norline map in regions with winter hardiness component trait QTL will enhance marker assisted selection for these important traits. DA - 2011/3// PY - 2011/3// DO - 10.2135/cropsci2010.04.0224 VL - 51 IS - 2 SP - 490-502 SN - 1435-0653 ER - TY - JOUR TI - High throughput Agrobacterium-mediated switchgrass transformation AU - Li, Ruyu AU - Qu, Rongda T2 - BIOMASS & BIOENERGY AB - Switchgrass is one of the most important biomass/bioenergy crops. For its improvement as a feedstock through biotechnological approach, we have developed a high throughput Agrobacterium-mediated transformation system for cv. Alamo and two new elite cultivars, Performer and Colony. Highly regenerable and transformation-competent embryogenic calli were identified and used for genetic transformation. GFP reporter gene was employed to identify transformation events at early stages and to guide modifications at various stages for improvement of transformation efficiency. The modifications included infection under vacuum, co-cultivation at desiccation conditions, resting between co-cultivation and selection, and supplement of L-proline in the callus culture and selection media. Transformation efficiency over 90% was routinely achieved for Performer, and around 50% for Alamo and Colony. The new system substantially improved switchgrass transformation efficiency and will significantly contribute to the genetic improvement of this important biofuel feedstock via biotechnological approach. DA - 2011/3// PY - 2011/3// DO - 10.1016/j.biombioe.2010.11.025 VL - 35 IS - 3 SP - 1046-1054 SN - 1873-2909 KW - Alamo KW - Colony KW - Genetic transformation KW - GFP KW - Panicum vertigam L KW - Performer ER - TY - JOUR TI - Field Evaluation of Four Level Spreader-Vegetative Filter Strips to Improve Urban Storm-Water Quality AU - Winston, R. J. AU - Hunt, William F., III AU - Osmond, D. L. AU - Lord, W. G. AU - Woodward, M. D. T2 - JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING AB - An assessment of the performance of four level spreader–vegetative filter strip (LS-VFS) systems designed to treat urban storm-water runoff was undertaken at two sites in the Piedmont of North Carolina. At each site, a 7.6-m grassed filter strip and a 15.2-m half-grassed, half-forested filter strip were examined. Monitored parameters included rainfall, inflow to, and outflow from each LS-VFS system. A total of 21 and 22 flow-proportional water quality samples were collected and analyzed for the Apex and Louisburg sites, respectively. All studied LS-VFS systems significantly reduced mean total suspended solids (TSS) concentrations (p<0.05), with the 7.6 and 15.2-m buffers reducing TSS by at least 51 and 67%, respectively. Both 15.2-m VFSs significantly reduced the concentrations of total Kjeldahl nitrogen (TKN), total nitrogen (TN), organic nitrogen (Org-N), and NH4-N (p<0.05), whereas results were mixed for the 7.6-m VFSs. Significant pollutant mass reduction was observed (p<0.05) for all nine pollutant forms analyzed in Louisburg, which was caused by infiltration in the VFSs. The effects of VFS length and/or vegetation type are very important for pollutant removal, as effluent pollutant concentrations were lower (with one exception) for the 15.2-m VFSs. The median effluent concentrations for TN and total phosphorus (TP) for the four LS-VFSs were nearly always better than fair water quality benchmarks for the Piedmont of North Carolina, but only met good water quality metrics in one-half of the studied storm events. DA - 2011/3// PY - 2011/3// DO - 10.1061/(asce)ir.1943-4774.0000173 VL - 137 IS - 3 SP - 170-182 SN - 1943-4774 KW - Vegetation KW - Filters KW - Sustainable development KW - Stormwater management KW - Water quality KW - Best Management Practice KW - Urban areas KW - North Carolina ER - TY - JOUR TI - Advancement in Assessment and the Reassessment of the Nutritive Value of Forages AU - Burns, J. C. T2 - CROP SCIENCE AB - ABSTRACT Forages, primary producers of carbon compounds, provide energy and nutrients when consumed by herbivores, resulting in “value‐added” animal products as meat, milk, and fiber and, in some cases, recreation. How a forage supports value‐added products of interest has been a concern since the mid 1800s. The characteristic of a forage that composes its nutritive value (NVAL) and its consumption and conversion by the animal determines the quality of the nutrient entity and provides an estimate of its forage quality. The first system to address forage NVAL emerged in the mid 1880s and was termed the Weende proximate analysis. Forages were separated into crude protein (CP), crude fiber (CF), ether extract (EE), nitrogen‐free extract (NFE), ash, and water. The concept of nutrient entity followed in the 1950s. By the mid 1960s, the neutral detergent fiber (NDF) system partially replaced proximate analysis and the two, along with innovations in solubility, serve as methodologies for estimating NVAL. An assessment of NVAL from the microbial view point was introduced in the early 1960s by the two‐stage in vitro dry matter disappearance (IVDMD) method, followed in the 1970s by continuous cultures. Innovation in spectral technology introduced near infrared spectrophotometry in the mid 1980s providing a rapid analysis of the NVAL fractions. A reassessment of the approach to estimating forage quality, based on the microflora's view of “particle value,” using near infrared spectral scans of the “as fed” forage has been proposed. DA - 2011/3// PY - 2011/3// DO - 10.2135/cropsci2010.06.0334 VL - 51 IS - 2 SP - 390-402 SN - 1435-0653 ER - TY - JOUR TI - Registration of 'SW049029104' Wheat AU - Griffey, C. A. AU - Thomason, W. E. AU - Pitman, R. M. AU - Beahm, B. R. AU - Gundrum, P. G. AU - Liu, S. Y. AU - Chen, J. AU - Paling, J. J. AU - Dunaway, D. W. AU - Brooks, W. S. AU - Vaughn, M. E. AU - Seago, J. E. AU - Will, B. C. AU - Hokanson, E. G. AU - Behl, H. D. AU - Corbin, R. A. AU - Lewis, T. R. AU - Hall, M. D. AU - Custis, J. T. AU - Starner, D. E. AU - Gulick, S. A. AU - Ashburn, S. R. AU - Whitt, D. L. AU - Bockelman, H. E. AU - Murphy, J. P. AU - Navarro, R. A. AU - Souza, E. J. AU - Brown-Guedira, G. L. AU - Kolmer, J. A. AU - Long, D. L. AU - Jin, Y. AU - Chen, X. AU - Cambron, S. E. T2 - JOURNAL OF PLANT REGISTRATIONS AB - ‘SW049029104’ (Reg. No. CV‐1053, PI 658599) soft red winter (SRW) wheat ( Triticum aestivum L.) was developed and released by the Virginia Agricultural Experiment Station in March 2009. SW049029104 was derived from the cross ‘38158’ (PI 619052)/Pioneer variety 2552//‘Roane’ and was tested under the experimental number VA04W‐90. SW049029104 is a broadly adapted, high‐yielding, moderately short, semidwarf (Rht2) cultivar that is resistant to powdery mildew [caused by Blumeria graminis (DC.) E.O. Speer] and Fusarium head blight (caused by Fusarium graminearum Schwabe). In the 2009 USDA‐ARS Uniform Southern SRW Wheat Nursery conducted at 25 locations, SW049029104 ranked first among 40 entries for grain yield (4889 kg ha −1 ) and fourth for grain volume weight (73.2 kg hL −1 ). The milling and baking qualities of SW049029104 exceeded those of ‘USG 3555’ and Pioneer brand 26R61. Flour softness and cookie‐spread diameter of SW049029104 (61.5–64.8 g 100 g −1 and 18.39–18.48 cm) exceeded those of USG 3555 (57.9–61.1 g 100 g −1 and 18.09–18.21 cm) and Pioneer brand 26R61 (54.5–61.1 g 100 g −1 and 18.12–18.13 cm). While flour protein concentration of SW049029104 (8.55–8.66 g 100 g −1 ) was lower than that of USG 3555 (8.88–9.10 g 100 g −1 ) and Pioneer brand 26R61 (9.65–9.66 g 100 g −1 ), its gluten strength, assessed via lactic acid solvent retention capacity (124.7–129.7 g 100 g −1 ), exceeded that of USG 3555 (118.9–124.0 g 100 g −1 ) and Pioneer brand 26R61 (113.5–126.0 g 100 g −1 ). DA - 2011/1// PY - 2011/1// DO - 10.3198/jpr2010.03.0146crc VL - 5 IS - 1 SP - 91-97 SN - 1936-5209 ER - TY - JOUR TI - Registration of 'Bailey' Peanut AU - Isleib, Thomas G. AU - Milla-Lewis, Susana R. AU - Pattee, Harold E. AU - Copeland, Susan C. AU - Zuleta, M. Carolina AU - Shew, Barbara B. AU - Hollowell, Joyce E. AU - Sanders, Timothy H. AU - Dean, Lisa O. AU - Hendrix, Keith W. AU - Balota, Maria AU - Chapin, Jay W. T2 - JOURNAL OF PLANT REGISTRATIONS AB - ‘Bailey’ (Reg. No. CV‐111, PI 659502) is a large‐seeded virginia‐type peanut ( Arachis hypogaea L. subsp. hypogaea var. hypogaea ) with partial resistance to five diseases that occur commonly in the Virginia‐Carolina production area: early leaf spot (caused by Cercospora arachidicola Hori), late leaf spot [caused by Cercosporidium personatum (Berk. & M.A. Curtis) Deighton], Cylindrocladium black rot [caused by Cylindrocladium parasiticum Crous, M.J. Wingf. & Alfenas], Sclerotinia blight (caused by Sclerotinia minor Jagger), and tomato spotted wilt (caused by Tomato spotted wilt tospovirus ). It also has partial resistance to southern stem rot (caused by Sclerotium rolfsii Sacc.). Bailey was developed as part of a program of selection for multiple‐disease resistance funded by growers, seedsmen, shellers, and processors. Bailey was tested under the experimental designation N03081T and was released by the North Carolina Agricultural Research Service (NCARS) in 2008. Bailey was tested by the NCARS, the Virginia Agricultural Experimental Station, and five other state agricultural experiment stations and the USDA‐ARS units participating in the Uniform Peanut Performance Tests. Bailey has an alternate branching pattern, an intermediate runner growth habit, medium green foliage, and high contents of fancy pods and medium virginia‐type seeds. It has approximately 34% jumbo and 46% fancy pods, seeds with tan testas and an average weight of 823 mg seed −1 , and an extra large kernel content of approximately 42%. Bailey is named in honor of the late Dr. Jack E. Bailey, formerly the peanut breeding project's collaborating plant pathologist. DA - 2011/1// PY - 2011/1// DO - 10.3198/jpr2009.12.0742crc VL - 5 IS - 1 SP - 27-39 SN - 1940-3496 ER - TY - JOUR TI - Genetic signals of origin, spread, and introgression in a large sample of maize landraces AU - Heerwaarden, Joost AU - Doebley, John AU - Briggs, William H. AU - Glaubitz, Jeffrey C. AU - Goodman, Major M. AU - Sanchez Gonzalez, Jose de Jesus AU - Ross-Ibarra, Jeffrey T2 - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA AB - The last two decades have seen important advances in our knowledge of maize domestication, thanks in part to the contributions of genetic data. Genetic studies have provided firm evidence that maize was domesticated from Balsas teosinte (Zea mays subspecies parviglumis), a wild relative that is endemic to the mid- to lowland regions of southwestern Mexico. An interesting paradox remains, however: Maize cultivars that are most closely related to Balsas teosinte are found mainly in the Mexican highlands where subspecies parviglumis does not grow. Genetic data thus point to primary diffusion of domesticated maize from the highlands rather than from the region of initial domestication. Recent archeological evidence for early lowland cultivation has been consistent with the genetics of domestication, leaving the issue of the ancestral position of highland maize unresolved. We used a new SNP dataset scored in a large number of accessions of both teosinte and maize to take a second look at the geography of the earliest cultivated maize. We found that gene flow between maize and its wild relatives meaningfully impacts our inference of geographic origins. By analyzing differentiation from inferred ancestral gene frequencies, we obtained results that are fully consistent with current ecological, archeological, and genetic data concerning the geography of early maize cultivation. DA - 2011/1/18/ PY - 2011/1/18/ DO - 10.1073/pnas.1013011108 VL - 108 IS - 3 SP - 1088-1092 SN - 0027-8424 ER - TY - JOUR TI - Site-Specific Weed Management in Cotton Using WebHADSS (TM) AU - Ford, A. J. AU - Dotray, P. A. AU - Keeling, J. W. AU - Wilkerson, J. B. AU - Wilcut, J. W. AU - Gilbert, L. V. T2 - WEED TECHNOLOGY AB - Field trials were established in 2005 and continued in 2006 to evaluate a conventional broadcast herbicide sprayer compared to a variable spray (sensor-activated) weed-sensing sprayer (WSS). The computer-based Herbicide Application Decision Support System (WebHADSS™) was used to determine a portion of the herbicides applied (based on herbicide efficacy and economics). Weed control, herbicide usage, crop yield, and net returns were compared across treatments. The broadcast applications were usually the most effective at controlling weeds. A PPI herbicide did not always improve weed control compared to treatments in which no PPI herbicide was applied. Variable treatments used less herbicide than the broadcast system in both years. Cotton lint yields in broadcast applications were similar to the weed-free check in both years of the study. Variable treatments often provided equivalent net returns (gross yield revenue less weed control cost) to the broadcast treatments. Although herbicide savings were observed in the variable treatments when compared to a broadcast system, a reduction in weed control was observed, indicating the need for future improvements of this system. A site-specific weed management program used in conjunction with WebHADSS™ may have potential in cotton production systems in the Texas Southern High Plains where weed densities are low. DA - 2011/// PY - 2011/// DO - 10.1614/wt-d-10-00060.1 VL - 25 IS - 1 SP - 107-112 SN - 1550-2740 KW - Decision support system KW - Fibermax 960 BR cotton KW - herbicide use KW - net return KW - weed control KW - weed-sensing sprayer KW - variable sprayer application ER - TY - JOUR TI - No-till can increase earthworm populations and rooting depths AU - Kemper, W. Doral AU - Schneider, Nicholas N. AU - Sinclair, Thomas R. T2 - JOURNAL OF SOIL AND WATER CONSERVATION AB - Crops grow by opening their stomata, which allow CO2 to enter their leaves, where CO2 and water can be photosynthesized into carbohydrates using the sun's energy. Photosynthesis occurs in the light only if CO2 continues to diffuse from the atmosphere into the interior of the leaves. However, stomata cannot remain open for CO2 diffusion if water is not continually supplied to the stomata to replenish the water these cells lose via transpiration. If the water flux from the soil is limited under drought conditions, stomata initiate closure and crop growth decreases. The soil profile is the critical storage reservoir, which can absorb and hold the rainfall until it is needed by the crop. The amount of rainfall that can be absorbed, stored, and made available for crop use depends on the porosity and texture of the soil and depth to which crop roots penetrate the soil. DA - 2011/// PY - 2011/// DO - 10.2489/jswc.66.1.13a VL - 66 IS - 1 SP - 13A-17A SN - 0022-4561 ER - TY - JOUR TI - Multiple Mid-Atlantic Field Experiments Show No Economic Benefit to Fungicide Application When Fungal Disease Is Absent in Winter Wheat AU - Weisz, Randy AU - Cowger, Christina AU - Ambrose, Gaylon AU - Gardner, Andrew T2 - PHYTOPATHOLOGY AB - Strobilurin fungicides produce intensified greening and delayed senescence in plants, and have been claimed to enhance yields of field crops in the absence of disease. To help evaluate this claim, available publicly sponsored tests of fungicides on soft red winter wheat in Virginia and North Carolina (n = 42) were analyzed for the period 1994 to 2010. All tests were replicated and had a randomized complete block, split-plot, or split-block design. Each test included 1 to 32 cultivars and one to five fungicides (two strobilurins, one triazole, and two strobilurin-triazole mixtures). There was a total of 311 test-cultivar-fungicide treatment comparisons, where a comparison was the reported yield difference between sprayed and unsprayed treatments of a given cultivar in a given test. Parameters used to calculate the economic benefit or loss associated with fungicide application included a grain price range of $73.49 to 257.21 Mg(-1) ($2 to 7 bu(-1)), a total fungicide application cost of $24.71 to 74.13 ha(-1) ($10 to 30 acre(-1)), and a 0.14 to 0.21 Mg ha(-1) (2.3 to 3.4 bu acre(-1)) loss in yield from driving over wheat during application (with a sprayer 27.4 or 18.3 m [90 or 60 feet] wide, respectively). The yield increase needed to pay for a fungicide application at each combination of cost and price was calculated, and the cumulative probability function for the fungicide yield-response data was modeled. The model was used to predict the probability of achieving a break-even yield, and the probabilities were graphed against each cost-price combination. Tests were categorized as "no-disease" or "diseased" based on reports of the researchers rating the tests. Subsets of the data were analyzed to assess the profitability of the triazole fungicide and the strobilurin-containing fungicides separately in no-disease versus diseased experiments. From the results, it was concluded that, with routine fungicide application based solely on wheat growth stage, total fungicide application costs had to be <$24.71 ha(-1) ($10 acre(-1)) in order to average a ≥ 50% probability of breaking even or making a profit (compared with not spraying). By contrast, if fungicides were applied when fungal disease was present, total application costs of ≤ $47 ha(-1) ($19 acre(-1)) for strobilurins and ≤ $72 ha(-1) ($29 acre(-1)) for propiconazole alone were associated with a ≥ 50% probability of breaking even or making a profit at a wheat price of $184 Mg(-1). The results do not support the application of strobilurin or triazole fungicides to mid-Atlantic wheat crops for "plant health" in the absence of disease. Rather, they support basing the decision to apply fungicide on observation of disease, if an economic return for the input is desired. DA - 2011/3// PY - 2011/3// DO - 10.1094/phyto-03-10-0096 VL - 101 IS - 3 SP - 323-333 SN - 0031-949X ER - TY - JOUR TI - Genome-wide association study of quantitative resistance to southern leaf blight in the maize nested association mapping population AU - Kump, Kristen L. AU - Bradbury, Peter J. AU - Wisser, Randall J. AU - Buckler, Edward S. AU - Belcher, Araby R. AU - Oropeza-Rosas, Marco A. AU - Zwonitzer, John C. AU - Kresovich, Stephen AU - McMullen, Michael D. AU - Ware, Doreen AU - Balint-Kurti, Peter J. AU - Holland, James B. T2 - NATURE GENETICS DA - 2011/2// PY - 2011/2// DO - 10.1038/ng.747 VL - 43 IS - 2 SP - 163-U120 SN - 1061-4036 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79251575784&partnerID=MN8TOARS ER - TY - JOUR TI - Genome-wide association study of leaf architecture in the maize nested association mapping population AU - Tian, Feng AU - Bradbury, Peter J. AU - Brown, Patrick J. AU - Hung, Hsiaoyi AU - Sun, Qi AU - Flint-Garcia, Sherry AU - Rocheford, Torbert R. AU - McMullen, Michael D. AU - Holland, James B. AU - Buckler, Edward S. T2 - NATURE GENETICS DA - 2011/2// PY - 2011/2// DO - 10.1038/ng.746 VL - 43 IS - 2 SP - 159-U113 SN - 1546-1718 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79251561130&partnerID=MN8TOARS ER - TY - JOUR TI - Effect of dietary boron on physiological responses in growing steers inoculated with bovine herpesvirus type-1 AU - Fry, R. S. AU - Brown, T. T., Jr. AU - Lloyd, K. E. AU - Hansen, S. L. AU - Legleiter, L. R. AU - Robarge, W. P. AU - Spears, J. W. T2 - RESEARCH IN VETERINARY SCIENCE AB - Thirty-six Angus and Angus × Simmental steers were fed one of three dietary treatments; (1) control (no supplemental B), (2) 5 mg supplemental B/kg, and (3) 15 mg supplemental B/kg for 47 days to determine the effects of dietary boron (B) on disease resistance following an inoculation with bovine herpesvirus type-1 (BHV-1). On day 34 of the study steers were inoculated intranasally with BHV-1. Rectal temperatures began to elevate at day 2, and plasma tumor necrosis factor-α concentrations increased (P < 0.05) by day 2 following BHV-1 inoculation. Plasma acute phase proteins were increased (P < 0.01) while plasma interferon-γ was decreased (P < 0.05) by day 4 post-inoculation. Supplementation of B increased (P < 0.001) plasma B concentrations in a dose-responsive manner. However, dietary B did not affect the duration and severity of clinical signs of BHV-1 and had minimal effects on plasma acute phase proteins and cytokines. DA - 2011/2// PY - 2011/2// DO - 10.1016/j.rvsc.2010.04.016 VL - 90 IS - 1 SP - 78-83 SN - 1532-2661 KW - Boron KW - Cattle KW - BHV-1 KW - Acute phase proteins KW - Cytokines KW - Plasma B ER - TY - JOUR TI - Cellulase Activity as a Mechanism for Suppression of Phytophthora Root Rot in Mulches AU - Richter, Brantlee Spakes AU - Ivors, Kelly AU - Shi, Wei AU - Benson, D. M. T2 - PHYTOPATHOLOGY AB - Wood-based mulches are used in avocado production and are being tested on Fraser fir for reduction of Phytophthora root rot, caused by Phytophthora cinnamomi. Research with avocado has suggested a role of microbial cellulase enzymes in pathogen suppression through effects on the cellulosic cell walls of Phytophthora. This work was conducted to determine whether cellulase activity could account for disease suppression in mulch systems. A standard curve was developed to correlate cellulase activity in mulches with concentrations of a cellulase product. Based on this curve, cellulase activity in mulch samples was equivalent to a cellulase enzyme concentration of 25 U ml –1 or greater of product. Sustained exposure of P. cinnamomi to cellulase at 10 to 50 U ml –1 significantly reduced sporangia production, but biomass was only reduced with concentrations over 100 U ml –1 . In a lupine bioassay, cellulase was applied to infested soil at 100 or 1,000 U ml –1 with three timings. Cellulase activity diminished by 47% between 1 and 15 days after application. Cellulase applied at 100 U ml –1 2 weeks before planting yielded activity of 20.08 μmol glucose equivalents per gram of soil water (GE g –1 aq) at planting, a level equivalent to mulch samples. Cellulase activity at planting ranged from 3.35 to 48.67 μmol GE g –1 aq, but no treatment significantly affected disease progress. Based on in vitro assays, cellulase activity in mulch was sufficient to impair sporangia production of P. cinnamomi, but not always sufficient to impact vegetative biomass. DA - 2011/2// PY - 2011/2// DO - 10.1094/phyto-04-10-0125 VL - 101 IS - 2 SP - 223-230 SN - 0031-949X ER - TY - JOUR TI - Application Placement Equipment for Bahiagrass (Paspalum notatum) Suppression along Roadsides AU - Gannon, Travis W. AU - Yelverton, Fred H. T2 - WEED TECHNOLOGY AB - Experiments were initiated during 2003 and 2004 to evaluate application placement equipment for plant growth regulator (PGR) applications along bahiagrass roadsides. Recently designed equipment combine low-volume application and pesticide placement technology. Application placement equipment conceal the image of a traditional spray application. Evaluated application placement equipment included a wet-blade mower (Burch Wet Blade) and rotary-wick applicator (Weedbug™) compared with a traditional broadcast spray. Wet-blade mowers are designed to mow and simultaneously apply a pesticide solution to a cut stem or leaf in a single pass, whereas rotary-wick applicators are designed to wick a solution onto foliage. Evaluated PGRs included imazapic (9, 35, or 53 g ha −1 ) and sulfometuron-methyl (26 g ha −1 ). Bahiagrass injury varied with application placement equipment and was greater with rotary-wick applications in 2003, compared with foliar broadcast applications and the wet-blade mower. Bahiagrass seedhead suppression ranged from 31 to 60% with application placement equipment in July 2003 compared with 93% for a broadcast spray. In 2004, rotary wick- or broadcast-applied PGRs provided excellent (> 90%) seedhead suppression. Although application placement equipment may have advantages to broadcast-spray applications, evaluated equipment did not enhance bahiagrass suppression along roadsides in North Carolina compared with a foliar broadcast spray. Additional research is needed to determine if this type of application may provide consistent results with other species and compounds. DA - 2011/// PY - 2011/// DO - 10.1614/wt-d-10-00074.1 VL - 25 IS - 1 SP - 77-83 SN - 1550-2740 KW - Seedhead suppression KW - plant growth regulator KW - low-volume application KW - wet blade KW - rotary wick KW - roadside turf ER - TY - JOUR TI - An accurate DNA marker assay for stem rust resistance gene Sr2 in wheat AU - Mago, R. AU - Brown-Guedira, Gina AU - Dreisigacker, S. AU - Breen, J. AU - Jin, Y. AU - Singh, R. AU - Appels, R. AU - Lagudah, E. S. AU - Ellis, J. AU - Spielmeyer, W. AU - al. T2 - THEORETICAL AND APPLIED GENETICS DA - 2011/3// PY - 2011/3// DO - 10.1007/s00122-010-1482-7 VL - 122 IS - 4 SP - 735-744 SN - 1432-2242 ER - TY - JOUR TI - Effects of soybean seed size on weed competition AU - Place, G.T. AU - Reberg-Horton, S.C. AU - Carter, T.E. AU - Smith, A.N. T2 - Agronomy Journal AB - Organic soybean [ Glycine max (L.) Merr.] producers must rely on various, nonherbicidal tactics for weed management. Increased soybean seed size may be one method to increase the competitiveness of the soybean canopy. Soybean varieties Hutcheson, NC‐Roy, and NC‐Raleigh were separated into four or five seed size classes. Seed sizes ranged from 5.15 to 6.75 mm diam. This range of seed size resulted in seed weights of 10 to 20 g per 100 seed. Each seed size class was grown in weedy and weed‐free conditions at Kinston, NC during 2007 and 2008 and at Plymouth, NC during 2008. Redroot pigweed ( Amaranthus retroflexus L.) overseeding was done to create uniform weed densities. Increasing soybean seed size resulted in greater soybean canopy coverage with the greatest effect at 3 weeks after emergence (WAE) ( P < 0.001, P = 0.003, and P < 0.001 at Kinston 2007, Kinston 2008, and Plymouth 2008, respectively) compared with 5 WAE ( P = 0.02, P = 0.07, and P = 0.02 at Kinston 2007, Kinston 2008, and Plymouth 2008, respectively). Plants from larger seed sizes had more soybean biomass in all sites when grown with weeds, but in only two sites under weed‐free conditions. Larger seed size improved soybean competitiveness by increasing petiole length and plant height. In the two sites with higher weed population densities, planting larger soybean seed reduced weed biomass at 7 WAE. Results suggest that use of larger planting seed may improve weed control in organic soybean production. DA - 2011/// PY - 2011/// DO - 10.2134/agronj2010.0195 VL - 103 IS - 1 SP - 175–181 SN - 1435-0645 ER -