@article{milla-lewis_zuleta_van esbroeck_quesenberry_kenworthy_2013, title={Cytological and Molecular Characterization of Genetic Diversity in Stenotaphrum}, volume={53}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2012.04.0234}, abstractNote={St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] is a warm‐season turfgrass broadly distributed across the southern United States. Here, we investigated genetic diversity and ploidy levels in publicly available plant introductions and cultivars of St. Augustinegrass as an aid to more effective use of these materials in breeding programs. Ploidy assignment of genotypes was problematic in some cases because of a lack of agreement between flow cytometry–inferred ploidy level and chromosome counts indicating that DNA content of higher ploidy genotypes was not a simple multiple of the diploid genome. Cytological investigations indicated five different ploidy levels (diploid, triploid, aneuploid, tetraploid, and hexaploid) with chromosome numbers ranging from 2n = 2x = 18 to 2n = 6x = 54. Principal coordinate and cluster analyses separated genotypes into distinct groups that were mostly congruent with ploidy levels. Moreover, analysis of molecular variance results based on amplified fragment length polymorphism genotyping indicated that 46% of the total variation could be explained by differences between ploidy levels. A clear positive correlation was observed between ploidy level and number of scored bands, with polyploids showing an increased number of bands. Variation in chromosome number is an important source of genetic variation in S. secundatum, and knowledge of the genetic relationships among accessions of this species can be an important consideration for the proper utilization of this germplasm in applied cultivar development.}, number={1}, journal={CROP SCIENCE}, publisher={Crop Science Society of America}, author={Milla-Lewis, Susana R. and Zuleta, M. Carolina and Van Esbroeck, George A. and Quesenberry, Kenneth H. and Kenworthy, Kevin E.}, year={2013}, month={Jan}, pages={296–308} }
 @article{chung_longfellow_walsh_kerdieh_van esbroeck_balint-kurti_nelson_2010, title={Resistance loci affecting distinct stages of fungal pathogenesis: use of introgression lines for QTL mapping and characterization in the maize - Setosphaeria turcica pathosystem}, volume={10}, ISSN={["1471-2229"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-77953126070&partnerID=MN8TOARS}, DOI={10.1186/1471-2229-10-103}, abstractNote={Abstract}, number={1}, journal={BMC PLANT BIOLOGY}, publisher={Springer Science \mathplus Business Media}, author={Chung, Chia-Lin and Longfellow, Joy M. and Walsh, Ellie K. and Kerdieh, Zura and Van Esbroeck, George and Balint-Kurti, Peter and Nelson, Rebecca J.}, year={2010}, month={Jun} }
 @article{balint-kurti_yang_van esbroeck_jung_smith_2010, title={Use of a Maize Advanced Intercross Line for Mapping of QTL for Northern Leaf Blight Resistance and Multiple Disease Resistance}, volume={50}, ISSN={["1435-0653"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-77749277550&partnerID=MN8TOARS}, DOI={10.2135/cropsci2009.02.0066}, abstractNote={Northern leaf blight [NLB; caused by Exserohilum turcicum (Pass) K.J. Leonard and E.G. Suggs] is an important fungal disease of maize (Zea mays L.) in the United States and worldwide. The IBM population, an advanced intercross recombinant inbred line population derived from a cross between the lines Mo17 and B73, was evaluated in three environments (Aurora, NY, in 2006 and 2007 and Clayton, NC in 2007) for two traits related to NLB resistance, weighted mean disease (WMD) and incubation period (IP), and for days to anthesis (DTA). Two WMD quantitative trait loci (QTL) in bins 2.00/2.01 and 4.08 were detected from the overall analysis; of these, only the QTL in bin 4.08 was detected in all three environments analyzed separately. Likewise, only one IP QTL, in bin 2.02, was detected in all three environments and from the overall analysis. Several environment‐specific QTL for each trait were also detected. Several DTA QTL were detected with the strongest effect detected in bin 8.05. Correlations between disease resistance traits and days to anthesis were uniformly low. The results from this study were compared to those of previous studies that used the IBM population to identify QTL for two other maize foliar diseases, southern leaf blight {causal agent Cochliobolus heterostrophus (Drechs.) Drechs. [anamorph = Bipolaris maydis (Nisikado and Miyake) Shoemaker; synonym = Helminthosporium maydis (Nisikado and Miyake)]} and gray leaf spot [causal agent Cercospora zeae‐maydis (Tehon and E.Y. Daniels)]. Although we did not find QTL conferring resistance to all three diseases, significant correlations between resistances to these diseases in the IBM population were identified, implying the existence of loci (and possibly genes) affecting resistance to all three diseases.}, number={2}, journal={CROP SCIENCE}, publisher={Crop Science Society of America}, author={Balint-Kurti, Peter J. and Yang, Junyun and Van Esbroeck, George and Jung, Janelle and Smith, Margaret E.}, year={2010}, pages={458–466} }
 @inproceedings{murphy_maxwell_miranda_lyerly_parks_srnic_perugini_cowger_marshall_van esbroeck_et al._2009, title={Qualitative powdery mildew mapping update}, booktitle={Eastern Wheat Workers/Southern Small Grain Workers NCERA184 Conference}, publisher={Baltimore, Md.: Eastern Wheat Workers/Southern Small Grain Workers}, author={Murphy, J. P. and Maxwell, J. J. and Miranda, L. M. and Lyerly, J. H. and Parks, W. R. and Srnic, G. and Perugini, L. and Cowger, C. and Marshall, D. and Van Esbroeck, G. and et al.}, year={2009}, pages={28–30} }
 @article{van esbroeck_corral_gonzalez_holland_2008, title={A Comparison of leaf appearance rates among teosinte, maize landraces and modern maize}, volume={53}, number={2}, journal={Maydica}, author={Van Esbroeck, G. A. and Corral, J. A. R. and Gonzalez, J. J. S. and Holland, J. B.}, year={2008}, pages={117–123} }
 @article{van esbroeck_bowman_may_calhoun_1999, title={Genetic similarity indices for ancestral cotton cultivars and their impact on genetic diversity estimates of modern cultivars}, volume={39}, number={2}, journal={Crop Science}, author={Van Esbroeck, G. A. and Bowman, D. T. and May, O. L. and Calhoun, D. S.}, year={1999}, pages={323–328} }
 @article{kiniry_tischler_van esbroeck_1999, title={Radiation use efficiency and leaf CO2 exchange for diverse C-4 grasses}, volume={17}, ISSN={["0961-9534"]}, DOI={10.1016/S0961-9534(99)00036-7}, abstractNote={Biomass accumulation of different grass species can be quantified by leaf area index (LAI) development, the Beer–Lambert light interception function, and a species-specific radiation-use efficiency (RUE). The object of this field study was to compare RUE values and leaf CO2 exchange rates (CER) for four C4 grasses. Biomass, LAI, and fraction of photosynthetically active radiation (PAR) intercepted were measured during three growing seasons. CER was measured on several dates and at several positions in the canopies. Switchgrass (Panicum virgatum L.) had the greatest RUE whereas sideoats grama [Bouteloua curtipendula (Michaux) Torrey] had the lowest. Big bluestem (Andropogon gerardii Vitman) and eastern gamagrass [Tripsacum dactyloides (L.) L.] values were intermediate. The two species with the greatest differences in RUE, switchgrass and sideoats grama, had similar relative amounts partitioned to roots. Likewise differences among species in the accumulation of soil carbon showed trends similar to total shoot biomass production. The light extinction coefficients (k) of switchgrass, big bluestem, and eastern gamagrass were smaller than for sideoats grama, implying that light was more effectively scattered down into the leaf canopy of the first three grasses. Whole canopy CER values were calculated with a stratified canopy approach, using LAI values, the Beer–Lambert formula with appropriate extinction coefficients, and CER light response curves. Differences among species in RUE were similar to these values for estimated whole-canopy CER divided by the fraction of light that was intercepted. High LAI along with low k contributed to higher RUE in switchgrass, in spite of lower values for single-leaf CER.}, number={2}, journal={BIOMASS & BIOENERGY}, author={Kiniry, JR and Tischler, CR and Van Esbroeck, GA}, year={1999}, pages={95–112} }
 @article{sanderson_reed_ocumpaugh_hussey_van esbroeck_read_tischler_hons_1999, title={Switchgrass cultivars and germplasm for biomass feedstock production in Texas}, volume={67}, ISSN={["0960-8524"]}, DOI={10.1016/S0960-8524(98)00132-1}, abstractNote={Switchgrass (Panicum virgatum L.) is a warm-season perennial grass indigenous to North America with excellent potential as a bioenergy crop. Our objective was to determine the yield potential and adaptability of switchgrass cultivars and germplasms in diverse Texas environments where the species might be used as a bioenergy crop. We determined the adaptability of several switchgrass cultivars and germplasms at five ecologically different locations (Beeville, College Station, Dallas, Stephenville, and Temple) in Texas in two experiments during 1992 to 1996. Alamo switchgrass was the best adapted commercially available switchgrass cultivar for biomass feedstock production in Texas in these trials with yields of 8 to 20 Mg ha−1. A single harvest in the fall maximized biomass yield and maintained switchgrass stands. Although very tolerant of moderate or even severe drought, switchgrass failed to yield under chronic extreme drought. At Beeville in 1996, there was no harvestable switchgrass growth because of extreme drought. Upland cultivars from the midwest matured early and did not produce as much biomass as lowland cultivars from the southern U.S. The predominant factor affecting switchgrass productivity in these Texas locations seemed to be rainfall amount. The highest biomass yield at each location generally occurred in years of greatest April to September rainfall. Soil type did not appear to have much influence on biomass production. Soil organic carbon increased from 11.1 to 15. 8 g kg−1 in the upper 30 cm of soil (average of four locations) during 1992 to 1996. These increases in organic carbon indicate a good potential for sequestering carbon through biomass production.}, number={3}, journal={BIORESOURCE TECHNOLOGY}, author={Sanderson, MA and Reed, RL and Ocumpaugh, WR and Hussey, MA and Van Esbroeck, G and Read, JC and Tischler, C and Hons, FM}, year={1999}, month={Mar}, pages={209–219} }
 @article{van esbroeck_bowman_van't hof_jividen_1999, title={Variation among cotton cultivars for the number of fiber initials per seed}, number={1999}, journal={Beltwide Cotton Conferences. Proceedings}, author={Van Esbroeck, G. A. and Bowman, D. T. and Van't Hof, J. and Jividen, G. M.}, year={1999}, pages={487} }
 @article{van esbroeck_bowman_calhoun_may_1998, title={Changes in the genetic diversity of cotton in the USA from 1970 to 1995}, volume={38}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci1998.0011183X003800010006x}, abstractNote={Despite concern about genetic vulnerability, little is known about the recent changes in the genetic diversity of upland cotton (Gossypium hirsutum L.). The objectives of this study were to determine the trends in the genetic diversity of upland cotton in the USA during the last 25 yr and to investigate probable causes for these changes. Two estimates of genetic diversity, coefficient of parentage (rp) and field uniformity (ri; rp weighted by the proportion of the hectarage occupied), were made for cultivars occupying over 1% of the hectarage within a region (Southeast, South‐central, Southwest, and West) from 1970 to 1995 at 5‐yr intervals. An average of 17 (range = 8–46) cultivars accounted for 97% of the cotton hectarage within a region. Regional rp values were relatively stable at 0.12 to 0.15 from 1970 to 1990 and then sharply increased to 0.20 in 1995. Higher rp values in commonly grown cultivars than in released cultivars indicated that much of the genetic diversity in cotton remains unused by growers. Field uniformity (ri) remained at about 0.30 for all regions during the past 25 yr because increases in rp were matched with an increase in the number of cultivars grown and/or a decline in the proportion of the area planted to any single cultivar. The frequent use of several parents for the creation of new cultivars and the planting of only a small portion of the available cultivars has led to a high level of genetic uniformity.}, number={1}, journal={CROP SCIENCE}, author={Van Esbroeck, GA and Bowman, DT and Calhoun, DS and May, OL}, year={1998}, pages={33–37} }
 @article{van esbroeck_bowman_1998, title={Cotton germplasm diversity and its importance to cultivar development}, volume={2}, number={3}, journal={Journal of Cotton Science}, author={Van Esbroeck, G. and Bowman, D. T.}, year={1998}, pages={121–129} }
 @article{van esbroeck_bowman_1998, title={Hybrid rank and variance of corn at sites with contrasting humic matter content}, volume={38}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci1998.0011183X003800020011x}, abstractNote={Widely adapted, high-yielding genotypes are most easily detected at sites in which differences among hybrids are large and where rankings are similar to the target environment. The objectives of this study were to determine if the relative yields, hybrid variances, and correlations with state-wide means for corn (Zea mays L.) hybrids differed among sites with low and high humic matter (HM) content. Five years of corn yield data from sites with contrasting HM content (0.032 vs. 0.059 g cm -3 ) located near Plymouth, NC, were collected. An analysis was performed for each year and maturity group which contained 12 to 48 hybrids. Mean yields averaged 12% (0.91 Mg ha -1 ) less at the high than low HM sites. Hybrid x HM interactions were significant (P < 0.05) in about half of all trials but rarely involved changes in the rank order among hybrids, indicating that duplicating trials on the two soil types was not warranted. Despite lower yields at the high HM sites, ranges and hybrid variances were larger in these sites. Maximum yields were less affected by soil type than minimum yields, indicating greater stress tolerance in high-yielding hybrids. A differential response among hybrids to some additional stress appeared to account for greater hybrid variances observed at the high HM sites. Correlations with state-wide mean performance were greater for high than low HM sites. Locating test sites on soils with high HM content may be an efficient way to detect hybrids capable of producing high yields under a range of soil and climatic conditions.}, number={2}, journal={CROP SCIENCE}, author={Van Esbroeck, GA and Bowman, DT}, year={1998}, pages={347–352} }
 @article{van esbroeck_hussey_sanderson_1998, title={Selection response and developmental basis for early and late panicle emergence in Alamo switchgrass}, volume={38}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci1998.0011183X003800020010x}, abstractNote={For many determinate crop species, delayed flowering, associated with the production of more mainstem leaves and/or a reduced rate of leaf appearance, extends the vegetative phase and results in higher biomass yields. Studies were carried out on 'Alamo' switchgrass (Panicum virgatum L.), a potential biofuel crop, to determine the realized heritability and developmental basis for variation in the time to panicle emergence. A single cycle of divergent selection for time of panicle emergence (earliest and latest 3%) was carried out. Time of panicle emergence for the parent and progeny generation was evaluated in the field for 2 yr and 1 yr in a greenhouse trial. For the parental generation, leaf emergence was monitored weekly and final leaf numbers were recorded. Panicle emergence for the selected early and late parents differed by an average of 22 d (10 d earlier and 12 d later than the original population). Realized heritabilities in the year following establishment were 1.0 and 0.92 for early and late panicle emergence, respectively. The early and late parent plants initiated growth at the same time in spring and produced leaves at the same rate; however, late plants produced from 0.7 to 2.1 more mainstem leaves than early plants. Similar leaf appearance rates, combined with higher final leaf numbers on late than on early plants, strongly suggested that late panicle emergence resulted from delayed floral initiation. This study showed that there is considerable genetic variation for flowering time in Alamo switchgrass and that the extended period of vegetative growth in late flowering types was associated with the production of more leaves.}, number={2}, journal={CROP SCIENCE}, author={Van Esbroeck, GA and Hussey, MA and Sanderson, MA}, year={1998}, pages={342–346} }
 @book{van esbroeck_bowman_may_1997, title={Pedigrees and distinguishing characteristics of upland and pima cotton germplasm lines released between 1972 and 1996}, publisher={Raleigh, N.C.: N.C. Agricultural Research Service, North Carolina State University}, author={Van Esbroeck, G. A. and Bowman, D. T. and May, O. L.}, year={1997} }