@article{jordan_wells_washburn_barnes_corbett_2022, title={Crop yield and estimated financial return from subsurface drip irrigation for corn, cotton, and peanut over the life of the system}, volume={8}, ISSN={["2374-3832"]}, DOI={10.1002/cft2.20167}, abstractNote={Core Ideas
Subsurface drip irrigation increased corn, cotton, and peanut yield in some (not all) years.
Financial returns over the irrigation system's life did not differ from dryland production.
Subsurface irrigation supports economic viability some years but not over the system's life.
}, number={2}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, author={Jordan, David and Wells, Randy and Washburn, Derek and Barnes, Steve and Corbett, Tommy}, year={2022} }
 @article{jordan_hare_wells_2022, title={Peanut response to a commercial blend of nitrogen, phosphorus, potassium, and fulvic acid}, volume={8}, ISSN={["2374-3832"]}, DOI={10.1002/cft2.20180}, abstractNote={Core Ideas
A commercial blend of nitrogen, phosphorus, potassium, and fulvic acid did not affect peanut yield.
Lack of response to the foliar product was consistent across diverse environments.
A commercial blend of nitrogen, phosphorus, potassium, and fulvic acid is not recommended.
}, number={2}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, author={Jordan, David L. and Hare, Andrew T. and Wells, Randy}, year={2022} }
 @article{finch_vann_wells_fisher_brown_2020, title={Impacts of lower-leaf removal timing, number, and nitrogen application to flue-cured tobacco}, volume={6}, ISSN={["2374-3832"]}, url={https://doi.org/10.1002/cft2.20059}, DOI={10.1002/cft2.20059}, abstractNote={AbstractThe removal and exclusion of lower‐stalk tobacco (Nicotiana tobacum L.) from harvest continues to be encouraged by industry. Very little information addresses the timing aspect of leaf removal, specifically when it occurs near floral initiation. Research was conducted in 2016 and 2017 to evaluate each possible treatment combination of two lower‐leaf removal programs (0 and 8 leaves/plant), three removal timings (2 wk before topping, at topping, and 2 wk after topping), and two N application rates (0 and 10 lb/ac). Soil plant analysis development (SPAD) measurements consistently revealed a lighter leaf color in treatments consisting of leaf removal 2 wk before topping, regardless of N application rate. Foliar cured leaf samples from upper‐stalk positions also contained less total N when eight leaves (2.25%) were removed relative to zero leaves (2.32%). These results indicate that subsequent N fertilizer application did not supply N as efficiently as remobilization from lower, older leaves. In the 8‐leaf removal program, both cured leaf yield and value declined by 27% relative to the 0‐leaf program. Despite significant losses in yield and value, the 8‐leaf program completely eliminated lug grades of tobacco. Leaf removal timing and N application rate did not affect yield, quality, value, or grade distribution. Our results suggest that there is no agronomic or cost to removing lower leaves 2 wk before or after topping; however, commercial farmers may find this information to be of use from a time management perspective, should they decide to implement this practice.}, number={1}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, publisher={Wiley}, author={Finch, Camden E. and Vann, Matthew C. and Wells, Randy and Fisher, Loren R. and Brown, A. Blake}, year={2020} }
 @article{finch_vann_fisher_wells_brown_2019, title={Lower-Leaf Removal and Nitrogen Application Programs for Flue-Cured Tobacco Production}, volume={111}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2018.10.0637}, abstractNote={Core Ideas
Lower‐leaf removal will reduce cured leaf yield but can reduce the portion of lower‐demand stalk positionsNitrogen application after leaf removal is of limited value and is currently discouragedIf these programs are to find commercial success, a higher selling price should be offered by leaf purchasers
With a current global over‐supply of flue‐cured tobacco (Nicotiana tabacum L.), tobacco producers in North Carolina have been encouraged to remove the lowermost leaves prior to harvest due to their low value in manufactured products. The objective of this research was to compare lower‐leaf removal programs. Research was conducted in 2016 and 2017 to quantify the agronomic effects of three lower‐leaf removal programs (0, 4, and 8 leaves plant−1) and the subsequent delivery of four N application rates (0, 5.6, 11.2, and 16.9 kg N ha−1 above base recommendation). All treatments combinations were applied during the early flowering stage of growth (8–10 wk after transplanting), when plants were approximately 120 cm tall. Programs absent of leaf removal generally produced the highest cured leaf yield. The addition of 16.9 kg N ha−1 increased yield when compared to lower N application rates within the 4‐leaf removal program. Nitrogen application did not affect yield in the 8‐leaf removal program. Cured leaf value was greatest in the 0‐leaf removal program (USD $10,131 ha−1) and was reduced in the 4‐ and 8‐leaf programs by $1611 and $2645 ha−1, respectively. Lower‐stalk positions were nearly eliminated in the 8‐leaf removal program, while the 4‐leaf removal program reduced their presence by more than 50%. Ultimately, if these programs are to be encouraged or required by industry, the removal of four leaves per plant proved to be more practical when paired with additional N, due to moderate yield reduction and lower‐stalk leaf production.}, number={4}, journal={AGRONOMY JOURNAL}, author={Finch, Camden E. and Vann, Matthew C. and Fisher, Loren R. and Wells, Randy and Brown, A. Blake}, year={2019}, pages={1933–1939} }
 @article{vann_fisher_wells_jordan_heitman_2017, title={Alternative Ridging Practices for Flue-Cured Tobacco Production in North Carolina}, volume={3}, ISSN={2374-3832}, url={http://dx.doi.org/10.2134/cftm2017.02.0016}, DOI={10.2134/cftm2017.02.0016}, abstractNote={Core Ideas
Alternative ridging methods could prove beneficial for tobacco producers.
Conservation tillage efforts have demonstrated little success.
Fine‐textured soils will require special management considerations.
Soil resistance is considered to be a limiting production factor.
Coarse‐textured soils appear to be better suited than fine‐textured soils.
With increasing farm size and the necessity for timely field preparation, flue‐cured tobacco (Nicotiana tabacum L.) producers in North Carolina would benefit from alternatives to current ridging practices. Research was conducted in 2012 and 2013 to evaluate the effects of differing ridging methods on soil physical properties and the growth and development of flue‐cured tobacco. In each environment, two alternative ridging methods were compared with the grower standard of spring ridging (SR): fall ridging (FR) and rotary ridging (RR) in the Piedmont, and FR and no ridging (NR) in the Coastal Plain. In the Piedmont, FR reduced leaf yield and value when compared with RR and SR systems. Reduced yield and value were a result of high soil resistance that inhibited plant growth. In the Coastal Plain, treatments imposed did not affect the soil physical properties or tobacco yield and quality. Results indicate that FR and NR systems are acceptable alternative ridging methods for the production of flue‐cured tobacco in the sandy Coastal Plain growing region. Alternatively, FR should not be used in the Piedmont growing region due to the fine soil texture that is prone to high resistance.}, number={1}, journal={Crop, Forage & Turfgrass Management}, publisher={Wiley}, author={Vann, Matthew C. and Fisher, Loren R. and Wells, Randy and Jordan, David L. and Heitman, Joshua L.}, year={2017}, month={Jun}, pages={cftm2017.02.0016} }
 @article{collins_edmisten_wells_whitaker_2017, title={The effects of mepiquat chloride applied to cotton at early bloom and physiological cutout}, volume={21}, number={3}, journal={Journal of Cotton Science}, author={Collins, G. D. and Edmisten, K. L. and Wells, R. and Whitaker, J. R.}, year={2017}, pages={183–189} }
 @article{wells_eickholt_lewis_vann_fisher_2016, title={Heat Unit Accumulation and Days to Anthesis Relationship in Tobacco Genotypes with an Introgressed QTL Affecting Leaf Number}, volume={56}, ISSN={["1435-0653"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84990194504&partnerID=MN8TOARS}, DOI={10.2135/cropsci2016.04.0278}, abstractNote={Plant breeders and crop managers would benefit from an increased ability to predict the requirements for onset of anthesis in tobacco (Nicotiana tabacum L.). This study was performed to determine the relationship in the field between heat unit (HU) accumulation and the onset of anthesis in tobacco genotypes varying for the zygosity of an introgressed quantitative trait loci (QTL) designated as Many Leaves (Ml) affecting flowering team and leaf number. Three commercially important cultivars or breeding lines (Speight 168, K326, and NCTG‐61), their nearly isogenic homozygous (MlMl) and heterozygous (Mlml) counterparts, and three BC6F3 null‐segregant (mlml) lines, were evaluated at three locations and over 2 yr. Days to anthesis (DTA) and HU accumulation were determined. In each environment, the MlMl, Mlml, and mlml genotypes were found to be grouped according to the zygosity of the Ml trait, with the mlml genotypes flowering first followed by Mlml and MlMl genotypes, respectively. An exception to this trend was Speight 168 MlMl, which consistently fell within the Mlml grouping for DTA. No consistent relationships were observed between HU and DTA, which was highly variable among environments. Integrated HU (area under the HU curve) during the 28 d after transplanting (DAT) was positively associated (R2 = 0.98; P = 0.0001) with the range of DTA among all genotypes. Integrated HU was a better indicator of the pattern of HU attainment than merely the amount. Early HU exposure seemed important in determining the range in DTA amongst the genotypes examined.}, number={6}, journal={CROP SCIENCE}, author={Wells, Randy and Eickholt, David P. J. and Lewis, Ramsey and Vann, Matthew C. and Fisher, Loren R.}, year={2016}, pages={3228–3236} }
 @article{foote_edmisten_wells_collins_roberson_jordan_fisher_2016, title={Influence of nitrogen and mepiquat chloride on cotton canopy reflectance measurements}, volume={20}, number={1}, journal={Journal of Cotton Science}, author={Foote, W. and Edmisten, K. and Wells, R. and Collins, G. and Roberson, G. and Jordan, D. and Fisher, L.}, year={2016}, pages={1–7} }
 @article{wells_2016, title={The use of obsolete and modern cultivars to examine advances in yield and dry matter partitioning}, volume={20}, number={3}, journal={Journal of Cotton Science}, author={Wells, R.}, year={2016}, pages={246–252} }
 @misc{foote_edmisten_wells_jordan_2015, title={Defoliant effects on cover crop germination, cover crop growth, and subsequent cotton (Gossypium hirsutum) development}, volume={19}, number={2}, journal={Journal of Cotton Science}, author={Foote, W. and Edmisten, K. and Wells, R. and Jordan, D.}, year={2015}, pages={258–267} }
 @article{riar_wells_edmisten_jordan_bacheler_2013, title={Cotton Yield and Canopy Closure in North Carolina as Influenced by Row Width, Plant Population, and Leaf Morphology}, volume={53}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2012.08.0490}, abstractNote={ABSTRACTCotton (Gossypium hirsutum L.) yield is partly determined by crop geometry, which is a function of row width and plant population. Field experiments were conducted in North Carolina during 2007 and 2008 to test the hypothesis that row width will be the determining factor in attaining canopy closure and hence greater fiber yield in North Carolina. The influences of both plant population and leaf morphology on the row width effects were also examined. Okra‐leaf (FiberMax 800 BR) and normal‐leaf (FiberMax 960 BR) cultivars were planted at 38‐ and 97‐cm row widths at populations of 7, 12, and 18 plants m−2. Cotton grown at 38‐cm row width yielded more than cotton grown at 97‐cm rows in some but not all environments. The percentage of canopy closure and the percentage of photosynthetically active radiation interception showed a close relationship over row width, leaf morphology, plant population, and environment (r2 = 0.84, P < 0.001). Higher plant population increased light interception and canopy closure early in the season. However, with time, these differences were reduced and were absent by the last observations. Row width was an important cause of greater canopy closure but this did not consistently translate into yield differences and yields were more closely affected by cumulative rainfall. Economic analysis found no loss of profit in the lowest plant population in either row width indicating that seed costs could be reduced without decreasing yield.}, number={4}, journal={CROP SCIENCE}, author={Riar, Ranjit and Wells, Randy and Edmisten, Keith and Jordan, David and Bacheler, Jack}, year={2013}, pages={1704–1711} }
 @article{viator_gwathmey_cothren_reed_vories_nuti_edmisten_wells_2008, title={Influence of ultranarrow row and conventional row cotton on the last effective boll population}, volume={100}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2007.0289}, abstractNote={The last effective boll population (LEBP) is the basis for many cotton (Gossypium hirsutum L.) management decisions such as defoliation timing. The objective of this research was to determine the last effective boll population based on first position bolls for both ultranarrow row cotton (UNRC), grown in rows spaced 25 cm or less, and conventional cotton (CONC) grown in rows spaced 96 to 102 cm. Experimental sites included locations in North Carolina, Tennessee, Mississippi, Arkansas, and Texas. At each site, UNRC and CONC plots were planted in a RCB design. At first flower, 15 plants per plot were flagged for subsequent flower tagging. On each flagged plant, all first position flowers were tagged every 2 d throughout the reproductive stage with date and nodes above white flower (NAWF) data for each plant. Tagged bolls were handpicked, sorted, counted, and seedcotton was weighed and recorded by NAWF for each plot. The last effective boll population was considered that NAWF position where cotton could be economically produced. Cotton could be produced economically at NAWF 2 and 3 for UNRC and CONC, respectively. Lint yield did not differ significantly between UNRC and CONC across site‐years. The UNRC produced the majority of seedcotton on NAWF 3 to 5, while CONC produced the most seedcotton at NAWF 4 to 6. Boll numbers showed a similar pattern. These data demonstrate that physiological cutout occurred at NAWF <5 in both UNRC and CONC.}, number={5}, journal={AGRONOMY JOURNAL}, author={Viator, Ryan P. and Gwathmey, C. Owen and Cothren, J. Tom and Reed, Jack T. and Vories, Earl D. and Nuti, Russell C. and Edmisten, Keith L. and Wells, Randy}, year={2008}, pages={1327–1331} }
 @article{stewart_edmisten_wells_collins_2007, title={Measuring canopy coverage with digital imaging}, volume={38}, ISSN={["0010-3624"]}, DOI={10.1080/00103620701277718}, abstractNote={Abstract Sampling plant canopies for their ability to intercept sunlight has traditionally been done with destructive or time‐consuming methods. Although nondestructive methods are available, they are either time consuming or subject to large variation. A commercially available software was utilized to analyze digital images of a cotton (Gossypium hirsutum L.) canopy in an effort to quantify canopy coverage. Digital images were obtained from a vertical perspective using a stationary camera stand. Images were analyzed using Adobe Photoshop 4.0 (Adobe Systems, Inc., Seattle, WA) software. Using functions within the software, plant material in the image was separated from the soil and converted to black. The soil surface was converted to white. The resulting black and white image was analyzed with Javascript software developed at North Carolina State University that counts the black and white pixels in each image. The resulting percentage of black pixels in the image was termed percent ground cover for the canopy. Percent ground cover was well correlated with leaf area index (LAI) over a low range of LAI with r2=0.74. This method provides a reasonable estimation of canopy coverage and proved to be a simple and efficient method of sampling a plant canopy. As image processing software becomes more refined, this and other techniques will become powerful tools for plant science research.}, number={7-8}, journal={COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS}, author={Stewart, Alexander M. and Edmisten, Keith L. and Wells, Randy and Collins, Guy D.}, year={2007}, pages={895–902} }
 @article{nuti_viator_casteel_edmisten_wells_2006, title={Effect of planting date, mepiquat chloride, and glyphosate application to glyphosate-resistant cotton}, volume={98}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2005.0360}, abstractNote={Management decisions and common misapplication of glyphosate may impact fruiting of glyphosate‐resistant (GR) cotton (Gossypium hirsutum L.). Experiments were conducted to determine if planting date affected the ability of GR cotton to compensate for fruit loss after misapplication of glyphosate and to evaluate mepiquat chloride's (MC) contribution to fruiting. Field studies were conducted in Rocky Mount, North Carolina, from 2001 to 2003. Treatments included optimum and late planting and a series of five glyphosate, 0.84 kg a.e. (acid equivalent) ha−1, treatments representing recommended and common misapplication timings including a control. The 10 planting date and glyphosate combinations were factored across treatments of MC and no‐MC as needed according to growing conditions in 2001 and 2002. All plots were treated with MC in 2003. Optimal‐planted cotton produced more than late‐planted cotton. Yield was reduced in optimal‐planted cotton in 2001 and late‐planted cotton in 2001 and 2002 when glyphosate contacted plants after the four‐leaf stage. Misapplication of gyphosate did not affect yield in 2003. Yield was improved with MC by 11% in 2001. Bolls were at higher nodes in late‐planted cotton and cotton not treated with MC. Glyphosate contact after the four‐leaf stage in 2001 and 2002 shifted the fruitload above Node 10. Late planting of cotton decreases opportunities for fruiting compensation when glyphosate reduced early boll retention. Results support previous research showing application methods that allow glyphosate contact to GR cotton plants after the four‐leaf stage increase risk of yield reduction regardless of planting date.}, number={6}, journal={AGRONOMY JOURNAL}, author={Nuti, Russell C. and Viator, Ryan P. and Casteel, Shaun N. and Edmisten, Keith L. and Wells, Randy}, year={2006}, pages={1627–1633} }
 @article{lanier_jordan_spears_wells_johnson_2005, title={Peanut response to inoculation and nitrogen fertilizer}, volume={97}, number={1}, journal={Agronomy Journal}, author={Lanier, J. E. and Jordan, D. L. and Spears, J. F. and Wells, R. and Johnson, P. D.}, year={2005}, pages={79–84} }
 @article{viator_nuti_edmisten_wells_2005, title={Predicting cotton boll maturation period using degree days and other climatic factors}, volume={97}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2005.0494}, abstractNote={Degree days are often used for cotton (Gossypium hirsutum L.) growth monitoring and management. The objectives of this research are to determine if 15.5°C is an accurate lower‐threshold temperature to monitor the boll maturation period (BMAP) for cotton in the northern, rainfed region of the U.S. Cotton Belt, to investigate other climatic factors in this cotton region that may improve the accuracy of the current degree day system for cotton, and to evaluate degree day models that include both an upper‐ and lower‐threshold temperature. Cotton was planted at three different timings in 2001 and 2002 to provide different climatic regimes during the BMAP. On 10 typical plants per plot, all first‐position flowers were individually tagged with date of flower opening and were then harvested at full maturity. Daily weather data consisted of maximum, minimum, and average air temperature; maximum and average soil temperature; average soil moisture; maximum and average solar radiation; and maximum and average photosynthetically active radiation. The 17°C degree day model, which used 17°C as the lower threshold, provided the best adjusted r2 (0.2715) of all the single‐variable models; the degree day 15.5°C model had an adjusted r2 of 0.2276. The best model using both upper and lower temperature thresholds was DD3017, using 30 and 17°C as the thresholds, and had an adjusted r2 of 0.2452. Adding average, minimum, and maximum air temperatures to the DD15.5, DD17, and DD3017 models reduced coefficient of variation and mean square error and increased adjusted r2 values.}, number={2}, journal={AGRONOMY JOURNAL}, author={Viator, RP and Nuti, RC and Edmisten, KL and Wells, R}, year={2005}, pages={494–499} }
 @article{viator_nuti_wells_edmisten_2005, title={Stem and root carbohydrate dynamics in modern vs. obsolete cotton cultivars}, volume={36}, ISSN={["1532-2416"]}, DOI={10.1080/00103620500196366}, abstractNote={Abstract Starch reserves in the lower stem and root are important sources of photoassimilates for completion of reproductive development in cotton. The objective of this research was to determine if carbohydrate levels in the lower stem and roots have been altered because of more than 100 years of breeding efforts. In 2001 and 2002, 33 cultivars released from 1900 to 2000 were evaluated. In addition, two elite lines were included in 2002. Plants were sampled at first bloom and cutout. Tissues were analyzed for starch content and concentration by using a colorimetric technique. Analysis of variance by year revealed cultivar differences for starch concentration at both sample times, but starch content was only significant at first bloom in 2002. These differences, though, did not show a strong relationship with release date, indicating that a century of breeding efforts had not altered stem and root starch dynamics. Orthogonal contrast did reveal differences in starch content and concentration between obsolete, modern, and elite lines. However, these differences were not consistent across experimental years. At first bloom in 2001, modern cultivars had lower root and stem starch concentrations, 69.8 and 63.6 mg g−1, compared to 94.5 and 84.8 mg g−1 for the obsolete lines. Modern cultivars also had lower root starch content, 537.5 mg, compared to 784.4 mg for the obsolete lines. At cutout in 2001, modern cultivars had lower root and stem starch concentrations, 20.6 and 20.9 mg g−1, compared 39.7 and 32.4 mg g−1 for the obsolete lines. Modern cultivars also had lower stem starch content, 349.0 mg, compared to 518.4 mg for the obsolete lines. These same trends were not seen in 2002. In 2002, modern cultivars did not differ from obsolete cultivars for all parameters. Elite lines, though, had higher stem starch concentrations at cutout, 56.9 mg g−1 compared to 39.5 and 46.6 mg g−1 for the obsolete and modern lines, respectively. Elite lines also had higher stem starch contents at cutout, 318.6 mg compared to 181.7 and 195.7 mg for the obsolete and modern lines, respectively. This higher stem starch concentration and content for elite lines may indicate higher photosynthetic rates. Environmental conditions seem to affect starch dynamics more than genetics when one considers the high significance of year on most data in this study.}, number={15-16}, journal={COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS}, author={Viator, RP and Nuti, R and Wells, R and Edmisten, K}, year={2005}, pages={2165–2177} }
 @article{thomas_burke_robinson_pline-srnic_edmisten_wells_wilcut_2005, title={Yield and physiological response of nontransgenic cotton to simulated glyphosate drift}, volume={19}, ISSN={["1550-2740"]}, DOI={10.1614/WT-03-194R}, abstractNote={Field studies were conducted in 2001 in Lewiston, NC, and in 2002 at Clayton and Lewiston, NC, to investigate the response of nontransgenic cotton to simulated glyphosate drift in a weed-free environment. Nontransgenic cotton variety ‘Fibermax 989’ was planted in a conventional seedbed at all locations. Glyphosate treatments were applied early postemergence (EPOST) at the four-leaf growth stage of cotton at 0, 8.7, 17.5, 35, 70, 140, 280, 560, and 1,120 g ai/ha and represent 0, 0.78, 1.55, 3.13, 6.25, 12.5, 25, 50, and 100% of the commercial use rate, respectively. Rates as low as 140 g/ha caused lint yield reductions depending on year and location. When averaged over all locations, lint yield reductions of 4, 49, 72, and 87% compared with nontreated cotton were observed with glyphosate rates of 140, 280, 560, and 1,120 g/ha, respectively. Visual injury and shikimic acid accumulation were evident at glyphosate rates greater or equal to 70 g/ha. Collectively, visual injury and shikimic acid accumulation at 7 d after EPOST treatment might be used as a diagnostic indicator to predict potential yield reductions from simulated glyphosate drift. Nomenclature: Glyphosate; cotton, Gossypium hirsutum L. ‘Fibermax 989’. Additional index words: Shikimic acid. Abbreviations: DAT, days after early postemergence treatment; DD, degree-day; EPOST, early postemergence; EPSPS, 5-enolpyruvylshikimate-3-phosphate synthase [EC 2.5.1.19]; HPLC, high-performance liquid chromatography; PDS, postemergence-directed; POST, postemergence; PRE, preemergence.}, number={1}, journal={WEED TECHNOLOGY}, author={Thomas, WE and Burke, IC and Robinson, BL and Pline-Srnic, WA and Edmisten, KL and Wells, R and Wilcut, JW}, year={2005}, pages={35–42} }
 @article{niyogi_chang_saxena_holt_alapaty_booker_chen_davis_holben_matsui_et al._2004, title={Direct observations of the effects of aerosol loading on net ecosystem CO2 exchanges over different landscapes}, volume={31}, ISSN={["0094-8276"]}, DOI={10.1029/2004gl020915}, abstractNote={We present the first direct, multisite observations in support of the hypothesis that atmospheric aerosols affect the regional terrestrial carbon cycle. The daytime growing season (summer) CO2 flux observations from six sites (forest, grasslands, and croplands) with collocated aerosol and surface radiation measurements were analyzed for high and low diffuse radiation; effect of cloud cover; and effect of high and low aerosol optical depths (AOD). Results indicate that, aerosols exert a significant impact on net CO2 exchange, and their effect may be even more significant than that due to clouds. The response appears to be a general feature irrespective of the landscape and photosynthetic pathway. The CO2 sink increased with aerosol loading for forest and crop lands, and decreased for grassland. The cause for the difference in response between vegetation types is hypothesized to be canopy architecture.}, number={20}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Niyogi, D and Chang, HI and Saxena, VK and Holt, T and Alapaty, K and Booker, F and Chen, F and Davis, KJ and Holben, B and Matsui, T and et al.}, year={2004}, month={Oct} }
 @article{lanier_jordan_barnes_matthews_grabow_griffin_bailey_johnson_spears_wells_2004, title={Disease management in overhead sprinkler and subsurface drip irrigation systems for peanut}, volume={96}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2004.1058}, abstractNote={Experiments were conducted during 2001 and 2002 at one location in North Carolina to compare development of early leaf spot (Cercospora arachidicola Hori), pod yield, and market grade characteristics when peanut (Arachis hypogea L.) was grown under overhead sprinkler irrigation (OSI) and subsurface drip irrigation (SDI) and fungicides were not applied or applied biweekly or based on weather advisories. Incidence of early leaf spot was lower when peanut was grown under SDI compared with OSI when fungicides were not applied. Fewer fungicide applications were needed when applications were based on weather advisories rather than when applied biweekly. There was no difference in early leaf spot control or leaf defoliation resulting from disease when fungicides were applied regardless of irrigation system or fungicide application approach. Pod yield was higher in 2001 under SDI compared with OSI when fungicides were not applied; yield was similar in 2002. Disease severity was much higher in 2001 than in 2002 and most likely explains differences in pod yield between years. No difference in yield was noted when fungicides were applied, regardless of irrigation system. The percentage of extra large kernels (%ELK) was lower in 1 of 2 yr under SDI compared with OSI. There were no differences in percentages of fancy pods (%FP), sound splits (%SS), and other kernels (%OK) among irrigation systems and fungicide programs. In a separate experiment where fungicides were applied biweekly, pod yield, %FP, and %ELK were similar under SDI and OSI but greater than nonirrigated peanut. The %OK was lower when peanut was irrigated.}, number={4}, journal={AGRONOMY JOURNAL}, author={Lanier, JE and Jordan, DL and Barnes, JS and Matthews, J and Grabow, GL and Griffin, WJ and Bailey, JE and Johnson, PD and Spears, JF and Wells, R}, year={2004}, pages={1058–1065} }
 @article{thomas_pline_wilcut_edmisten_wells_viator_paulsgrove_2004, title={Glufosinate does not affect floral morphology and pollen viability in glufosinate-resistant cotton}, volume={18}, ISSN={["1550-2740"]}, DOI={10.1614/WT-03-032R1}, abstractNote={Studies were conducted to determine whether glufosinate treatments to glufosinate-resistant cotton caused changes in floral morphology, pollen viability, and seed set. Four glufosinate treatments were included: (1) glufosinate applied postemergence over the top (POST) at the four-leaf stage, (2) glufosinate applied POST at the eight-leaf stage, (3) the first two treatments sequentially, and (4) a POST application at the four-leaf stage followed by (fb) a postemergence-directed stem application (PDS) at the eight-leaf stage. Glufosinate was consistently applied at 0.49 kg ai/ha. A nontreated control was included. Glufosinate treatments did not affect stigma height, length of the staminal column, or pollen viability. However, the distance from the top anther to the tip of the stigma was less in plants treated with an eight-leaf POST treatment than in nontreated plants, although this difference is not likely to influence pollen deposition because in both cases anthers reached above the stigma tip. Plants receiving four-leaf POST fb eight-leaf PDS treatment with glufosinate had eight seeds per boll less than nontreated plants; however, the more rigorous four-leaf POST fb eight-leaf POST treatment did not differ from the nontreated in seeds per boll.}, number={2}, journal={WEED TECHNOLOGY}, author={Thomas, WE and Pline, WA and Wilcut, JW and Edmisten, KL and Wells, R and Viator, RR and Paulsgrove, MD}, year={2004}, pages={258–262} }
 @article{thomas_pline-srnic_thomas_edmisten_wells_wilcut_2004, title={Glyphosate negatively affects pollen viability but not pollination and seed set in glyphosate-resistant corn}, volume={52}, ISSN={["1550-2759"]}, DOI={10.1614/WS-03-134R}, abstractNote={Abstract Experiments were conducted in the North Carolina State University Phytotron greenhouse and field locations in Clayton, Rocky Mount, and Lewiston-Woodville, NC, in 2002 to determine the effect of glyphosate on pollen viability and seed set in glyphosate-resistant (GR) corn. Varieties representing both currently commercial GR corn events, GA21 and NK603, were used in phytotron and field studies. All glyphosate treatments were applied at 1.12 kg ai ha−1 at various growth stages. Regardless of hybrid, pollen viability was reduced in phytotron and field studies with glyphosate treatments applied at the V6 stage or later. Scanning electron microscopy of pollen from affected treatments showed distinct morphological alterations correlating with reduced pollen viability as determined by Alexander stain. Transmission electron microscopy showed pollen anatomy alterations including large vacuoles and lower starch accumulation with these same glyphosate treatments. Although pollen viability and pollen production were reduced in glyphosate treatments after V6, no effect on kernel set or yield was found among any of the reciprocal crosses in the phytotron or field studies. There were also no yield differences among any of the hand self-pollinated (nontreated male × nontreated female, etc.) crosses. Using enzyme-linked immunosorbent assay to examine CP4-5-enolpyruvlshikimate-3-phosphate synthase expression in DKC 64-10RR (NK603) at anthesis, we found the highest expression in pollen with progressively less in brace roots, ear leaf, anthers, roots, ovaries, silks, stem, flag leaf, and husk. Nomenclature: Glyphosate; corn, Zea mays L.; ‘DK 662RR’; ‘DK 687RR’; ‘DKC 64-10RR/SIL’.}, number={5}, journal={WEED SCIENCE}, author={Thomas, WE and Pline-Srnic, WA and Thomas, JF and Edmisten, KL and Wells, R and Wilcut, JW}, year={2004}, pages={725–734} }
 @article{lanier_jordan_spears_wells_johnson_barnes_hurt_brandenburg_bailey_2004, title={Peanut response to planting pattern, row spacing, and irrigation}, volume={96}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2004.1066}, abstractNote={Experiments were conducted from 1999 through 2002 in North Carolina to compare interactions of planting pattern, plant population, and irrigation on peanut (Arachis hypogaea L.) pod yield and market grade characteristics. In additional experiments, pod yield and severity of tomato spotted wilt tospovirus associated with the cultivars NC‐V 11, NC 12C, VA 98R, and Perry were compared in single row (rows spaced 91 cm apart) and standard twin row (two rows spaced 18 cm apart on 91‐cm centers) planting patterns when peanut was dug and vines inverted on two digging dates spaced 10 to 16 d apart. In a third set of experiments, pod yield, market grade characteristics, and severity of tomato spotted wilt tospovirus were compared when the cultivars NC‐V 11 and Perry were planted in single row, standard twin row, and narrow twin row (two rows spaced 18 cm apart on 46‐cm centers) planting patterns. Peanut pod yield was higher in standard twin row planting patterns than when grown in single row planting patterns in some but not all experiments. Planting peanut in the narrow twin row pattern did not increase peanut pod yield over the standard twin row planting pattern. Less tomato spotted wilt was observed in standard or narrow twin row planting patterns compared with single row planting patterns. Planting peanut in single rows spaced 46 cm apart did not improve yield over peanut planted in single rows spaced 91 cm apart or the standard twin row planting pattern, regardless of irrigation treatment.}, number={4}, journal={AGRONOMY JOURNAL}, author={Lanier, JE and Jordan, DL and Spears, JF and Wells, R and Johnson, PD and Barnes, JS and Hurt, CA and Brandenburg, RL and Bailey, JE}, year={2004}, pages={1066–1072} }
 @article{rinehardt_edmisten_wells_faircloth_2004, title={Response of ultra-narrow and conventional spaced cotton to variable nitrogen rates}, volume={27}, ISSN={["1532-4087"]}, DOI={10.1081/PLN-120030379}, abstractNote={Abstract Insufficient nitrogen (N) uptake in cotton (Gossypium hirsutum L.) has been shown to delay maturity and decrease lint yields, while excessive amounts will cause a host of disadvantages, ranging from increased insect damage to defoliation difficulties. Proper nitrogen fertilization rates are therefore essential to maximizing lint production while minimizing input costs. This test was designed to determine if ultra–narrow row cotton (UNRC) has similar nitrogen requirements as conventional row cotton (CRC). Two sites, one in peanuts and the other fallow the previous growing season, and four nitrogen rates (45, 67, 90, and 112 kg N ha−1) were used to compare soil fertility and nitrogen effects on petiole nitrate concentrations, lint yields, and ginning percentages. Although petiole nitrate concentrations between early and peak bloom were lower in ultra–narrow row cotton with 45 and 67 kg N ha−1, there was no correlation between petiole nitrate concentrations and lint yield. Conventional spacing receiving 67 kg N ha−1 had the highest lint production at both locations, while application of 90 kg N ha−1 produced the highest yields in UNRC at both locations. Ultra–narrow row cotton produced numerically higher yields than conventional row at all nitrogen rates at the location without a previous legume crop, but no significant trend was observed. Ultra–narrow row cotton lint percentages were significantly lower than conventional spacing, independent of nitrogen application rate.}, number={4}, journal={JOURNAL OF PLANT NUTRITION}, author={Rinehardt, JM and Edmisten, KL and Wells, R and Faircloth, JC}, year={2004}, pages={743–755} }
 @article{faircloth_edmisten_wells_stewart_2004, title={The  influence of defoliation timing on yields and quality of two cotton cultivars}, volume={44}, DOI={10.2135/cropsci2004.1650}, abstractNote={The timing of certain cotton (Gossypium hirsutum L.) management practices varies according to the yield potential and quality characteristics associated with a variety. A defoliation timing study was performed to (i) determine if certain cultivars respond differently to defoliation timings and (ii) compare the use of the open boll percentage at defoliation (OBPD), nodes above cracked boll (NACB), and micronaire readings at defoliation for their effectiveness in timing defoliation. The study was conducted in 1999, 2000, and 2001. Treatments consisted of two proprietary cultivars (ST 474 and DP 5409), each defoliated on the basis of OBPD measurements. At the time of defoliation, NACB was recorded and lint samples were retained for later high volume instrumentation (HVI) analysis. Neither variety produced consistently higher yields than the other in this study. In 2000, delaying defoliation from 40 to 60 OBPD would have resulted in a significant addition of approximately 75 kg lint ha−1 for either variety. Stoneville 474 micronaire was highest in all years suggesting that timely defoliation is more critical to ST 474 cotton compared with DP 5409 in years when overall conditions are favorable for high micronaire. DP 5409 fiber length (UHM) values were consistently higher than ST 474 and UHM was unaffected by changes in OBPD values regardless of variety. Stoneville 474 had higher uniformity index (UI) values in all three years and delaying defoliation produced mixed results. The data demonstrate that proper defoliation timing strategies aimed at optimizing quality can vary across varieties. Proper defoliation timing in the two varieties examined in this study varied little with respect to yields. Both NACB and micronaire readings taken at defoliation were more effective for timing defoliation to optimize micronaire readings than OBPD.}, number={1}, journal={Crop Science}, author={Faircloth, J. C. and Edmisten, K. L. and Wells, R. and Stewart, A. M.}, year={2004}, pages={165–172} }
 @article{faircloth_edmisten_wells_stewart_2004, title={Timing defoliation applications for maximum yields and optimum quality in cotton containing a fruiting gap}, volume={44}, DOI={10.2135/cropsci2004.1580}, abstractNote={Stresses during cotton (Gossypium hirsutum L.) square and boll formation can result in fruit abscission from several continuous nodes, resulting in a fruiting gap on the plant. This gap may cause a shift in benchmarks for timing various agronomic practices aimed at maximizing cotton yield and optimizing quality. A cotton defoliation timing study was performed in 1999, 2000, and 2001 to (i) see if the creation of a fruiting gap would influence defoliation timing and to (ii) compare the use of the open boll percentage at defoliation (OBPD), nodes above cracked boll (NACB), and micronaire readings at defoliation as tools for timing defoliation. In late July or early August each year, a fruiting gap was created by physically removing fruit from several continuous nodes on plants. Plots were defoliated on the basis of various OBPD values. Upon defoliation, OBPD and NACB were taken and lint was retained to determine the micronaire at defoliation. In both 1999 and 2000, there was a yield advantage to delaying defoliation beyond 60 OBPD in treatments containing a gap. However, in 2001 there was no yield advantage to delaying defoliation. This may have been due to optimal late‐season growing conditions experienced in 2001. In years when micronaire readings are high, data suggested cotton not containing a fruiting gap is more likely to be above discount levels for high micronaire and should not be defoliated past 60 OBPD. In both 1999 and 2000, trends confirmed a direct relationship between OBPD and both yield and micronaire. Overall, these studies demonstrated that in some years, where no fruiting gaps exist, it might be possible to terminate cotton before the 60% open boll recommendation without sacrificing yields. These results would allow farmers to shift defoliation, and hence harvest, to a time when there are fewer risks of quality‐based discounts. While a significant interaction prohibited the examination of the use of micronaire at defoliation as a technique for timing defoliation, there did not appear to be a significant advantage to using either NACB or OBPD for timing defoliation.}, number={1}, journal={Crop Science}, author={Faircloth, J. C. and Edmisten, K. L. and Wells, R. and Stewart, A. M.}, year={2004}, pages={158–164} }
 @article{pline_wells_little_edmisten_wilcut_2003, title={Glyphosate and water-stress effects on fruiting and carbohydrates in glyphosate-resistant cotton}, volume={43}, DOI={10.2135/cropsci2003.0879}, abstractNote={Crop ScienceVolume 43, Issue 3 p. 879-885 Crop Physiology & Metabolism Glyphosate and Water-Stress Effects on Fruiting and Carbohydrates in Glyphosate-Resistant Cotton Wendy A. Pline, Wendy A. Pline Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire, RG42 6ET U.K.Search for more papers by this authorRandy Wells, Randy Wells Dep. of Crop Science, North Carolina State Univ., Raleigh, NC, 27695-7620Search for more papers by this authorGary Little, Gary Little Dep. of Crop Science, North Carolina State Univ., Raleigh, NC, 27695-7620Search for more papers by this authorKeith L. Edmisten, Keith L. Edmisten Dep. of Crop Science, North Carolina State Univ., Raleigh, NC, 27695-7620Search for more papers by this authorJohn W. Wilcut, Corresponding Author John W. Wilcut john_wilcut@ncsu.edu Dep. of Crop Science, North Carolina State Univ., Raleigh, NC, 27695-7620Corresponding author (john_wilcut@ncsu.edu)Search for more papers by this author Wendy A. Pline, Wendy A. Pline Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire, RG42 6ET U.K.Search for more papers by this authorRandy Wells, Randy Wells Dep. of Crop Science, North Carolina State Univ., Raleigh, NC, 27695-7620Search for more papers by this authorGary Little, Gary Little Dep. of Crop Science, North Carolina State Univ., Raleigh, NC, 27695-7620Search for more papers by this authorKeith L. Edmisten, Keith L. Edmisten Dep. of Crop Science, North Carolina State Univ., Raleigh, NC, 27695-7620Search for more papers by this authorJohn W. Wilcut, Corresponding Author John W. Wilcut john_wilcut@ncsu.edu Dep. of Crop Science, North Carolina State Univ., Raleigh, NC, 27695-7620Corresponding author (john_wilcut@ncsu.edu)Search for more papers by this author First published: 01 May 2003 https://doi.org/10.2135/cropsci2003.8790Citations: 9Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract Water stress and glyphosate treatments to glyphosate-resistant (GR) cotton (Gossypium hirsutum L.) can cause abscission of young bolls although the interaction of these factors is not well defined. Studies were conducted to quantify the effects of water stress and glyphosate treatments on fruit retention, fruit placement, and carbohydrate partitioning in GR and conventional cotton varieties grown in a phytotron environment. Glyphosate-resistant plants treated with glyphosate at the four-leaf stage, postemergence (POST), and at the eight-leaf stage, POST-directed (PDIR), had fewer first-position bolls after 0 and 1 d of water stress than nontreated GR and conventional plants but did not differ after 2 and 3 d of water stress. Glyphosate-treated GR plants reached first bloom 3 to 4 d later than nontreated plants. Five-day-old bolls from plants of one genotype, SG 125RR, treated with glyphosate had lower fructose content than bolls from nontreated plants. Subtending leaf carbohydrates and boll sucrose, glucose, and starch content did not differ after glyphosate treatments. Increasing water stress caused reductions in subtending leaf glucose, sucrose, and starch content, as well as reductions in boll starch and sucrose content. Reductions in boll starch and sucrose content in response to water stress may indicate the potential for abscission. Water stress and glyphosate treatments to GR cotton do not alter carbohydrate profiles in boll or leaf tissues in a like manner. Differences in carbohydrate profiles of young bolls and leaves from glyphosate-treated and water-stressed cotton plants suggest that water stress and glyphosate treatments may promote fruit abscission in different manners. Citing Literature Volume43, Issue3May–June 2003Pages 879-885 RelatedInformation}, number={3}, journal={Crop Science}, author={Pline, W. A. and Wells, R. and Little, G. and Edmisten, K. L. and Wilcut, J. W.}, year={2003}, pages={879–885} }
 @article{pline_edmisten_wilcut_wells_thomas_2003, title={Glyphosate-induced reductions in pollen viability and seed set in glyphosate-resistant cotton and attempted remediation by gibberellic acid (GA(3))}, volume={51}, ISSN={["0043-1745"]}, DOI={10.1614/0043-1745(2003)051[0019:GIRIPV]2.0.CO;2}, abstractNote={Abstract Glyphosate treatments to glyphosate-resistant (GR) cotton can cause increased fruit loss compared with untreated plants, likely due to reductions in pollen viability and alterations in floral morphology that may reduce pollination efficiency. This study was conducted to determine whether both stamen and pistil are affected by glyphosate treatments by measuring seed set from reciprocal reproductive crosses made between glyphosate-treated GR, untreated GR, and conventional nontransgenic cotton. Pollen viability was 51 and 38% lower for the first and second week of flowering, respectively, in GR plants treated with a four-leaf postemergence (POST) treatment and an eight-leaf POST-directed treatment of glyphosate than in GR plants that were not treated. Seed set per boll was significantly reduced when the pollen donor parent was glyphosate treated vs. untreated for the first 2 wk of flowering. There were no significant differences between treatments applied to male parents as measured by seed set at Weeks 3 and 4 of flowering. Seed set was not influenced by glyphosate treatments applied to female parents at any time. Retention of bolls resulting from crosses was reduced by glyphosate treatment of male parents during the first and third week of flowering but was not affected by glyphosate treatment of female parents. The application of gibberellic acid (GA), which has been shown to reverse male sterility in tomato (Lycopersicon esculentum L.) and to enhance boll retention in cotton, was investigated for similar effects in glyphosate-treated GR cotton. The GA treatments to glyphosate-treated plants increased the anther–stigma distance 12-fold, stigma height, and pollen viability in the second week of flowering but decreased the number of seeds in second-position bolls on Fruiting branches 1 through 3, decreased the number of first-position bolls per plant, and increased the number of squares in comparison with glyphosate-treated GR plants not receiving GA. Although GA applications to glyphosate-treated GR cotton have some remedial effect on pollen viability, the GA-induced increase in the anther–stigma difference exacerbates the increase in anther–stigma distance caused by glyphosate, resulting in low pollination. Nomenclature: Glyphosate; cotton, Gossypium hirsutum L. ‘Delta Pine & Land 5415RR’, ‘Delta Pine & Land 5415’.}, number={1}, journal={WEED SCIENCE}, author={Pline, WA and Edmisten, KL and Wilcut, JW and Wells, R and Thomas, J}, year={2003}, pages={19–27} }
 @article{pline_wilcut_edmisten_wells_2002, title={Physiological and morphological response of glyphosate-resistant and non-glyphosate-resistant cotton seedlings to root-absorbed glyphosate}, volume={73}, ISSN={["1095-9939"]}, DOI={10.1016/S0048-3575(02)00014-7}, abstractNote={The level of tolerance in herbicide-resistant plants may vary among different tissues or growth stages. Studies were conducted to determine relative tissue sensitivity in glyphosate-resistant (GR) and non-GR cotton seedlings to the herbicide glyphosate. Glyphosate is often applied as a pre-plant treatment (burndown) in minimal tillage cotton production systems to remove any unwanted, emerged vegetation. Timing of these glyphosate applications may be in close proximity to the time of planting and seedling emergence. As glyphosate leaches from roots of nearby senescing weeds, it may be absorbed into the roots of cotton seedlings. Therefore, cotton seedlings were grown in hydroponic solutions containing technical grade glyphosate to ensure constant exposure to glyphosate. In all tissues, GR cotton required a greater concentration of glyphosate to reach 50% fresh weight reduction than non-GR cotton. Glyphosate inhibited the growth of non-GR cotton cotyledons, hypocotyls, and roots 50% at concentrations of 23, 69, and 27μM glyphosate, respectively. In contrast, growth of GR cotton cotyledons, hypocotyls, and roots was inhibited by 50% at 3.5-, 8-, and 5-fold greater glyphosate concentrations, respectively, than non-GR cotton tissues. Correspondingly, shikimic acid, an intermediate in the shikimic acid pathway, which accumulates upon 5-enolpyruvyl 3-shikimate phosphate synthase (EPSP synthase) inhibition, reached levels of 17.3, 21.6, and 8.8μMg−1 fresh weight at 1 mM glyphosate in non-GR cotyledons, hypocotyls, and roots, respectively. In contrast, shikimic acid levels in GR cotton were 4.2, 14.0, and 8.2μMg−1 fresh weight at 1 mM glyphosate for cotyledons, hypocotyls, and roots, respectively. Thus, roots of GR and non-GR cotton accumulate similar amounts of shikimic acid, whereas GR cotyledons and hypocotyls accumulated less shikimic acid than the corresponding non-GR tissues in response to glyphosate treatments. Additionally, glyphosate inhibited the development of lateral roots at concentrations of 0.01 or 0.1μM glyphosate greater, in GR and non-GR cotton, respectively. Lateral roots of GR and non-GR cotton inhibited by glyphosate appeared shorter and were surrounded by a thick layer of necrotic cells or root exudate which was not present in roots from plants grown in media not containing glyphosate. The quantity of GR CP4-EPSP synthase was 4.7 and 6.6 times greater in cotyledons than in hypocotyls and roots, respectively. Tissues from dark-grown GR cotton seedlings contained 1.2–2.1 times less CP4-EPSP synthase than their light-grown counterparts. Because lateral root development was inhibited, fresh weight was reduced, and shikimic acid accumulated following treatment with glyphosate in both GR and non-GR cotton, the potential exists for glyphosate to negatively affect cotton seedling establishment.}, number={1}, journal={PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY}, author={Pline, WA and Wilcut, JW and Edmisten, KL and Wells, R}, year={2002}, month={May}, pages={48–58} }
 @article{pline_viator_wilcut_edmisten_thomas_wells_2002, title={Reproductive abnormalities in glyphosate-resistant cotton caused by lower CP4-EPSPS levels in the male reproductive tissue}, volume={50}, ISSN={["0043-1745"]}, DOI={10.1614/0043-1745(2002)050[0438:RAIGRC]2.0.CO;2}, abstractNote={Abstract Glyphosate treatments to glyphosate-resistant (GR) cotton have been associated with poor pollination and increased boll abortion. Anatomical studies were conducted to characterize the effect of glyphosate treatments on the development of male and female reproductive organs of cotton flowers at anthesis. In comparison with nontreated plants, glyphosate applied at both the four-leaf stage postemergence (POST) and at the eight-leaf stage POST directed inhibited the elongation of the staminal column and filament, which increased the distance from the anthers to the receptive stigma tip by 4.9 to 5.7 mm during the first week of flowering. The increased distance from the anthers to the stigma resulted in 42% less pollen deposited on stigmas of glyphosate-treated plants than in nontreated plants. Moreover, pollen from glyphosate-treated plants showed numerous morphological abnormalities. Transmission electron microscopy showed the presence of large vacuoles, numerous starch grains, and less organized pockets of the endoplasmic reticulum containing fewer ribosomes in pollen from glyphosate-treated plants than from nontreated plants. Pollen development in glyphosate-treated plants is likely inhibited or aborted at the vacuolate microspore and vacuolate microgamete stages of microgametogenesis, resulting in immature pollen at anthesis. Although stigmas from glyphosate-treated plants were 1.2 to 1.4 mm longer than those from nontreated plants, no other anatomical differences in stigmas were visibly evident. The presence of the GR 5-enolpyruvylshikimate-3-phosphate synthase (CP4-EPSPS) enzyme from Agrobacterium sp. strain CP4 was quantified in reproductive and vegetative tissues using enzyme-linked immunosorbent assay. The content of CP4-EPSPS in the stigma, anther, preanthesis floral bud (square), and flower petals was significantly less than that in the vegetative leaf tissue. Glyphosate effects on the male reproductive development resulting in poor pollen deposition on the stigma, as well as production of aborted pollen with reduced viability, provide a likely explanation for reports of increased boll abortion and pollination problems in glyphosate-treated GR cotton. Nomenclature: Glyphosate; cotton, Gossypium hirsutum L. ‘Delta Pine & Land 5415RR’, ‘Delta Pine & Land 50’, ‘Delta Pine & Land 90’, ‘SureGrow 125RR’.}, number={4}, journal={WEED SCIENCE}, author={Pline, WA and Viator, R and Wilcut, JW and Edmisten, KL and Thomas, J and Wells, R}, year={2002}, pages={438–447} }
 @article{wells_2002, title={Stem and root carbohydrate dynamics of two cotton cultivars bred fifty years apart}, volume={94}, DOI={10.2134/agronj2002.8760}, abstractNote={Little is known concerning carbohydrate pools within the nonleaf and nonreproductive portions of the cotton (Gossypium hirsutum L.) plant. A 2‐yr field study was conducted to ascertain both the concentration and total content of soluble carbohydrate and starch in upper stems, lower stems, vegetative branches, and roots of two cultivars released approximately 50 yr apart [Deltapine (DPL) 14 and 5690] from the same breeding program. In addition, yield, canopy photosynthesis, nodes above white flower, and white flowers per square meter were measured in the second year. Cultivar main effect was significant for soluble carbohydrate, total carbohydrate (soluble carbohydrate + starch), root dry weight, and total stem and root dry weight per plant. These differences are reflected by the generally greater dry weight and larger soluble carbohydrate concentration of DPL 5690 at 143 d after planting in 1994. Deltapine 5690 also exhibited larger late‐season, integrated canopy photosynthesis in 1994, attributing to its larger soluble carbohydrate content. There was an initial increase in total stem and root carbohydrate per plant in each year followed by a decrease. Timing of the maxima and minima differed between years and between cultivars in 1994. Both the upper/lower stem carbohydrate ratios and the upper/lower stem starch ratios indicate declining upper‐stem carbohydrate as flowering approached a hiatus and a shift in carbohydrate content towards the lower half of the stem. The data indicate that carbohydrate concentration and content per plant vary throughout the season; however, the cultivars exhibited little alteration in carbohydrate trends due to breeding efforts.}, number={4}, journal={Agronomy Journal}, author={Wells, R.}, year={2002}, pages={876–882} }
 @article{pline_edmisten_oliver_wilcut_wells_allen_2002, title={Use of digital image analysis, viability stains, and germination assays to estimate conventional and glyphosate-resistant cotton pollen viability}, volume={42}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2002.2193}, abstractNote={AbstractBecause the success of labor‐intensive hand crosses by breeders is dependent upon pollen viability, quick, simple, and inexpensive methods for viability assessment are of interest. Four such cotton pollen viability assays were compared to determine differences in viability estimates, and relative accuracy by correlation to seed set. The methods compared were Brewbaker & Kwack (B & K) medium, B & K medium plus aniline blue, a fluorochromatic reaction method (FCR), and Alexander's stain. Additionally, digital images of germinated pollen grains were analyzed by means of morphometry software to quantify pollen tube area per pollen grain, as a proposed additional method of assessing viability. Pollen from conventional, nontreated glyphosate‐resistant (GR) and glyphosate‐treated GR cotton (Gossypium hirsutum L.) plants was tested by each method. Glyphosate treatments to GR cotton reduced pollen viability and corresponding seed set in all methods tested. Pollen germination measured by the B & K method was most closely related to seed set per boll, while Alexander's stain gave the highest estimates of viability. The FCR method indicated that many pollen grains from glyphosate‐treated GR cotton were irregularly shaped and only partially flourescein diacetate (FD) stained. All methods tested showed similar high correlation (0.7–0.8) of pollen viability to seed set. Morphometric analysis of digital images of germinated pollen found the greatest pollen tube area to pollen grain ratio with B & K medium + 30 mM sucrose. Because the B & K method most closely predicted the linear magnitude of seed set reduction to reduced pollen viability, allowed the use of morphometry software analysis, and was one of the simplest and least equipment‐demanding methods, it may provide broad utility for those assessing cotton pollen viability.}, number={6}, journal={CROP SCIENCE}, author={Pline, WA and Edmisten, KL and Oliver, T and Wilcut, JW and Wells, R and Allen, NS}, year={2002}, pages={2193–2200} }
 @article{pline_price_wilcut_edmisten_wells_2001, title={Absorption and translocation of glyphosate in glyphosate-resistant cotton as influenced by application method and growth stage}, volume={49}, ISSN={["0043-1745"]}, DOI={10.1614/0043-1745(2001)049[0460:AATOGI]2.0.CO;2}, abstractNote={Abstract The influence of herbicide placement and plant growth stage on the absorption and translocation patterns of 14C-glyphosate in glyphosate-resistant cotton was investigated. Plants at four growth stages were treated with 14C-glyphosate on a 5-cm2 section of the stem, which simulated a postemergence-directed spray (PDS) application, or on the newest mature leaf, which simulated a postemergence (POST) application. Plants were harvested 3 and 7 d after treatment and divided into the treated leaf or treated stem, mature leaves, immature leaves and buds, stems, roots, fruiting branches (including the foliage on the fruiting branch), squares, and bolls. The PDS versus POST application main effect on absorption was significant. Absorption of 14C-glyphosate applied to stem tissue was higher in PDS applications than in POST applications. Plants receiving PDS applications absorbed 35% of applied 14C-glyphosate, whereas those receiving POST applications absorbed 26%, averaged over growth stages at application. Absorption increased from the four-leaf growth stage to the eight-leaf stage in POST applications but reached a plateau at the eight-leaf stage. Plants with PDS applications showed an increase in absorption from the four- to eight- to twelve-leaf stages and reached a plateau at the 12-leaf stage. Translocation of 14C-glyphosate to roots was greater at all growth stages with PDS treatments than with POST treatments. Herbicide placement did not affect translocation of 14C-glyphosate to squares and bolls. Squares and bolls retained 0.2 to 3.7% of applied 14C-glyphosate, depending on growth stage. Separate studies were conducted to investigate the fate of foliar-applied 14C-glyphosate at the four- or eight-leaf growth stages when harvested at 8- or 10-leaf, 12-leaf, midbloom (8 to 10 nodes above white bloom), and cutout (five nodes above white bloom, physiological maturity) stages. Thirty to 37% of applied 14C-glyphosate remained in the plant at cutout in four- and eight-leaf treatment stages, respectively. The concentration of 14C-glyphosate in tissue (Bq g−1 dry weight basis) was greatest in mature leaves and immature leaves and buds in plants treated at the four-leaf stage. Plants treated at the eight-leaf stage and harvested at all growth stages except cutout showed a higher concentration of 14C-glyphosate in squares than in other plant tissue. Accumulation of 14C-glyphosate in squares reached a maximum of 43 Bq g−1 dry weight at harvest at the 12-leaf stage. This concentration corresponds to 5.7 times greater accumulation of 14C-glyphosate in squares than in roots, which may also be metabolic sinks. These data suggest that reproductive tissues such as bolls and squares can accumulate 14C-glyphosate at higher concentrations than other tissues, especially when the herbicide treatment is applied either POST or PDS during reproductive stages (eight-leaf stage and beyond). Nomenclature: Glyphosate; cotton, Gossypium hirsutum L. ‘Delta Pine 5415RR’.}, number={4}, journal={WEED SCIENCE}, author={Pline, WA and Price, AJ and Wilcut, JW and Edmisten, KL and Wells, R}, year={2001}, pages={460–467} }
 @article{wells_2001, title={Leaf pigment and canopy photosynthetic response to early flower removal in cotton}, volume={41}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2001.4151522x}, abstractNote={Loss of reproductive organs from cotton (Gossypium hirsutum L.) often results in compensatory growth that culminates in altered morphologic, physiologic, and photosynthetic patterns. This field study examined the change in leaf chlorophyll (Chl) and anthocyanin (Ant) contents and their relationship to canopy photosynthetic patterns in response to the removal of flowers for the first 2 wk of flowering. Flower removal caused an extended flowering period in all years except 1995 when temperatures were highest. The largest yield differences occurred in 1994, while there were no significant differences in any other year. Differences in canopy photosynthesis occurred on at least one date in each year that measurements were made. In 1997, significant differences were observed on four dates and plants from the removal treatment had 15% larger area under the seasonal photosynthetic curve. Chlorophyll concentrations were higher in leaves from the flower removal treatment after 100 d after planting. Anthocyanin levels were higher in controls during the same period, indicating significant negative relationships between Ant levels and either Chl a/b ratio or Chl concentration. Pigment differences late in plant ontogeny appeared to be associated with delayed senescence of plants from the removal treatment. While pigment levels late in development were associated with canopy photosynthesis, not all treatment differences could be related to Chl loss. In 2 yr, significant differences in canopy photosynthesis occurred prior to differences in Chl concentration, implicating other morphological and physiological adaptations in response to early fruit loss.}, number={5}, journal={CROP SCIENCE}, author={Wells, R}, year={2001}, pages={1522–1529} }
 @article{cui_carter_burton_wells_2001, title={Phenotypic diversity of modern Chinese and North American soybean cultivars}, volume={41}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2001.1954}, abstractNote={Chinese and North American (NA) soybean breeding programs have a 70‐yr history of genetic progress in relative isolation from each other. Because both programs rest upon a genetic base that is primarily Chinese in origin, the actual genetic distinctness of Chinese and NA breeding is not clear. The objectives of this study were to (i) develop a phenotypic similarity (PS) index for a large group of Chinese and NA cultivars, on the basis of biochemical, morphological, and agronomic traits, (ii) compare Chinese and NA cultivars for PS through cluster analysis, and (iii) use results to develop guidelines for management of the contrasting Chinese and NA breeding programs as reservoirs of diversity. Chinese (47) and NA (25) cultivars were evaluated for 25 traits in growth chambers. Traits pleiotropic to maturity were avoided. Significant (P < 0.05) differences between Chinese and NA cultivars were noted for leaf and seed traits. Multivariate analysis captured 79% of the total genotypic variation among the 72 cultivars and was used to develop PS estimates. Cluster analysis of PS showed a much greater phenotypic diversity among Chinese than among NA cultivars and a striking distinctness between the two groups. The contrasting nature of Chinese and NA cultivars in this study is theorized to reflect that (i) the NA cultivars may trace to a subset of the Chinese cultivar genetic base, and/or (ii) Chinese and NA cultivars may have diverged phenotypically via breeder selection pressure. Cluster results here, based on PS, agreed roughly with previous cluster analyses, which were derived from pedigree analysis. The physical distinctness of NA and Chinese cultivars shows that introgression of Chinese cultivars into NA breeding should broaden NA germplasm's agronomic, morphological, and biochemical diversity. Introgression may be accomplished most effectively by avoiding matings of Chinese and NA cultivars from the same phenotypic cluster.}, number={6}, journal={CROP SCIENCE}, author={Cui, ZL and Carter, TE and Burton, JW and Wells, R}, year={2001}, pages={1954–1967} }
 @article{anis-ur-rehman_isleib_2001, title={Reproductive allocation on branches of Virginia-type peanut cultivars bred for yield in North Carolina}, volume={41}, number={1}, journal={Crop Science}, author={Anis-Ur-Rehman, W. R. and Isleib, T. G.}, year={2001}, pages={72–77} }
 @article{pline_wilcut_duke_edmisten_wells_2002, title={Tolerance and accumulation of shikimic acid in response to glyphosate applications in glyphosate-resistant and nonglyphosate-resistant cotton (Gossypium hirsutum L.)}, volume={50}, ISSN={["0021-8561"]}, DOI={10.1021/jf0110699}, abstractNote={Measurement of shikimic acid accumulation in response to glyphosate inhibition of 5-enolpyruvylshikimate-3-phosphate synthase is a rapid and accurate assay to quantify glyphosate-induced damage in sensitive plants. Two methods of assaying shikimic acid, a spectrophotometric and a high-performance liquid chromatography (HPLC) method, were compared for their accuracy of recovering known amounts of shikimic acid spiked into plant samples. The HPLC method recovered essentially 100% of shikimic acid as compared with only 73% using the spectrophotometric method. Relative sensitivity to glyphosate was measured in glyphosate-resistant (GR) and non-GR cotton leaves, fruiting branches, and squares (floral buds) by assaying shikimic acid. Accumulation of shikimic acid was not observed in any tissue, either GR or non-GR, at rates of 5 mM glyphosate or less applied to leaves. All tissues of non-GR plants accumulated shikimic acid in response to glyphosate treatment; however, only fruiting branches and squares of GR plants accumulated a slight amount of shikimic acid. In non-GR cotton, fruiting branches and squares accumulated 18 and 11 times, respectively, more shikimic acid per micromolar of translocated glyphosate than leaf tissue, suggesting increased sensitivity to glyphosate of reproductive tissue over vegetative tissue. GR cotton leaves treated with 80 mM of glyphosate accumulated 57 times less shikimic acid per micromolar of translocated glyphosate than non-GR cotton but only 12.4- and 4-fold less in fruiting branches and squares, respectively. The increased sensitivity of reproductive structures to glyphosate inhibition may be due to a higher demand for shikimate pathway products and may provide an explanation for reports of fruit abortion from glyphosate-treated GR cotton.}, number={3}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Pline, WA and Wilcut, JW and Duke, SO and Edmisten, KL and Wells, R}, year={2002}, month={Jan}, pages={506–512} }
 @article{stewart_edmisten_wells_2000, title={Boil openers in cotton: effectiveness and environmental influences}, volume={67}, DOI={10.1016/s0378-4290(00)00093-9}, abstractNote={The indeterminate growth of cotton (Gossypium hirsutum L.) often results in a boll population at various stages of maturity when the crop is harvested. Boll opening compounds can be used to facilitate harvest by accelerating the opening of green bolls. Field trials were conducted at two locations in 1996 and 1997 to test the efficacy of four commercially available boll openers that stimulate ethylene production or desiccate the plant. Two of these boll openers are new to the marketplace: Finish™, ethephon+cyclanilide (2-chloroethyl phosphonic acid+1-(2,4-dichlorophenylaminocarbonyl)-cyclopropane carboxylic acid), and CottonQuick™, ethephon+AMADS (2-chloroethyl phosphonic acid+1-aminomethanamide dihydrogen tetraoxosulfate). Open bolls were hand harvested at 3–7 days intervals after application of the boll openers, and environmental conditions in conjunction with these harvests were recorded. The desiccant, paraquat (1,1′-dimethyl-4,4′-bipyridinium dichloride), was found to have erratic boll opening activity. Two products that contain ethephon plus the synergists cyclanilide or AMADS were found to have equal or higher rates of boll opening than ethephon alone. The rate of boll opening of all compounds was influenced more by the accumulation of heat units than by the amount of time following the application of boll openers. Although erratic, boll opening activity from paraquat application can be significant. Moreover, the reliability of ethephon based products, which are consistent boll openers, may be enhanced by formulations that contain a synergist. Heat unit accumulation may be used to predict and model the efficacy of boll opening with these harvest aides.}, number={1}, journal={Field Crops Research}, author={Stewart, E. M. and Edmisten, K. L. and Wells, R.}, year={2000}, pages={83–90} }
 @article{cawley_edminsten_wells_stewart_1999, title={Evaluation of ultra narrow row cotton in North Carolina}, volume={1}, number={1999}, journal={Beltwide Cotton Conferences. Proceedings}, author={Cawley, N. and Edminsten, K. and Wells, R. and Stewart, A.}, year={1999}, pages={558–559} }
 @article{stewart_edmisten_wells_1999, title={Mepiquat chloride applications with a canvas wick}, number={1999}, journal={Beltwide Cotton Conferences. Proceedings}, author={Stewart, A. M. and Edmisten, K. L. and Wells, R.}, year={1999}, pages={526} }
 @article{jones_wells_1998, title={Fiber yield and quality of cotton grown at two divergent population densities}, volume={38}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci1998.0011183X003800050013x}, abstractNote={Poor seed germination and early seedling damage often reduce plant populations in the north‐eastern cotton (Gossypium hirsutum L.) producing region of the USA. A field study was conducted at Clayton, NC, on a Dothan sandy loam (fine‐loamy, siliceous, thermic Plinthic Kandiudult) to investigate responses of cotton reproductive development to reduced plant population. All flowers on plants grown at 2 and 12 plants m−2 were tagged so that associations among boll and lint quantity and quality, flowering date, and fruiting position could be determined. On plants grown at 2 plants m−2, 33 and 65% of their fiber came from flowers initiated before 88 days after planting (DAP) in 1992 and 1993, respectively. Plants grown at 12 plants m−2 produced 63 and 88% of their fiber from flowers initiated before 88 DAP in 1992 and 1993, respectively. Plant population did not affect total lint yield, however. Because of favorable late‐season weather, plants grown at 2 plants m−2 produced more bolls on vegetative branches and at more distal sympodial positions than did plants grown at 12 plants m−2. Boll weight and micronaire were generally higher for earlier bolls at all positions for the lower population density. Later bolls exhibited poorer boll and fiber properties, indicating negative effects of reduced heat unit accumulation by later bolls. Our findings indicate that replanting, which might delay stand establishment by 3 to 4 wk, would be of little help toward improving fiber yield because it would rely more heavily on later produced bolls.}, number={5}, journal={CROP SCIENCE}, author={Jones, MA and Wells, R}, year={1998}, pages={1190–1195} }
 @article{mian_wells_carter_ashley_boerma_1998, title={RFLP tagging of QTLs conditioning specific leaf weight and leaf size in soybean}, volume={96}, ISSN={["0040-5752"]}, DOI={10.1007/s001220050748}, abstractNote={Selection for high specific leaf weight (SLW) in soybean [Glycine max (L) Merr.] may increase apparent photosynthetic rate per unit leaf area (AP), which in turn may improve seed yield. In general, the SLW and leaf size are negatively correlated in soybean. To maximize total photosynthetic performance, and perhaps the seed yield, of a soybean cultivar, it would be necessary to establish a large leaf area rapidly while maintaining a high SLW. The objective of the present study was to identify quantitative trait loci (QTLs) conditioning SLW and leaf size in soybean. One hundred and twenty F4-derived lines from a 'Young'×PI416937 population were evaluated using restriction fragment length polymorphism (RFLP) markers. The genetic map consisted of 155 loci on 33 linkage groups (LGs) covering 973 cM of map distance. The phenotypic data were collected from two different environments - a greenhouse at Athens, Ga. and a field site at Windblow, N.C. The SLW and leaf-size measurements were made on leaves from the 8th and 9th node of soybean plants at the V12 stage of development. Combined over environments, six putative independent RFLP markers were associated with SLW, and four of these loci were consistent across environments. Individually, the six markers each explained between 8 and 18% of the phenotypic variation among lines for SLW. The Young alleles contributed to a greater SLW at four of the six independent marker loci, and transgressive segregation occurred among the progeny for SLW. Three putative independent RFLP markers were associated with leaf size, each explaining between 6 to 11% of the phenotypic variation in the trait, and one of these markers was identified in both environments. There was no correlation between SLW and leaf size in this population. Similarly, none of the six QTLs conditioning SLW were linked to any of the three QTLs for leaf size. In this soybean population, it is possible to select for progeny lines with greater SLW than either parent perhaps without affecting the leaf size. It is feasible to pyramid all of the desirable alleles for greater SLW and large leaf size in a single genetic background.}, number={3-4}, journal={THEORETICAL AND APPLIED GENETICS}, author={Mian, MAR and Wells, R and Carter, TE and Ashley, DA and Boerma, HR}, year={1998}, month={Mar}, pages={354–360} }
 @article{jones_wells_1997, title={Dry matter allocation and fruiting patterns of cotton grown at two divergent plant populations}, volume={37}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci1997.0011183X003700030017x}, abstractNote={Reduced plant populations frequently occur in the northern Cotton Belt of the USA because of poor seed germination and early seedling damage. A field study was conducted at Clayton, NC, on a Dothan sandy loam (fine‐loamy, siliceous, thermic Plinthic Paleudult) to investigate the response of cotton (Gossypium hirsutum L.) vegetative and reproductive development to two plant populations. Cotton plants, grown at 2 and 12 plants m−2 in 1.0‐m rows had every flower tagged with week‐specific, color‐coded tags. Dry matter partitioning, flower development, flower retention, and boll development patterns were determined. Plants at the low population exhibited large increases in the vegetative dry weight of individual plants at maturity; however, all parameters of vegetative growth were reduced on a land area basis. Reproductive development of the 2 plants m−2 treatment was prolonged because of fewer early fruiting sites per unit land area and there was an average 16‐d delay in flowering maxima. No differences in total flowers per meter or flower retention occurred between treatments at final harvest. Slight differences in total bolls per meter occurred in 1993 (13% fewer bolls at 2 plants m−2); however, the low population plants had more bolls on monopodia, more late‐season flowers, and greater retention of these late bolls. Replanting low populations would not be advisable because the delay in maturity would probably be more injurious to boll production than the low population per se.}, number={3}, journal={CROP SCIENCE}, author={Jones, MA and Wells, R}, year={1997}, pages={797–802} }
 @article{burkey_wilson_wells_1997, title={Effects of canopy shade on the lipid composition of soybean leaves}, volume={101}, DOI={10.1034/j.1399-3054.1997.1010320.x}, number={3}, journal={Physiologia Plantarum}, author={Burkey, K. O. and Wilson, R. F. and Wells, R.}, year={1997}, pages={591–598} }
 @article{wells_1997, title={The birth, life, and death of the photosynthetic factory or the top ten reasons why: cotton photosynthesizes like it does and why we love it so}, volume={2}, number={1997}, journal={Beltwide Cotton Conferences. Proceedings}, author={Wells, R.}, year={1997}, pages={1347–1351} }
 @article{wells_1993, title={DYNAMICS OF SOYBEAN GROWTH IN VARIABLE PLANTING PATTERNS}, volume={85}, ISSN={["0002-1962"]}, DOI={10.2134/agronj1993.00021962008500010009x}, abstractNote={AbstractReported soybean [Glycine max (L.) Merr.] yield responses to variable plant populations have been inconsistent. The varied responses are tied to the capacity of the plant stand to attain a minimal level of dry matter prior to reproductive growth. This study examined soybean growth expressed as functions of both plant and ground area to identify associations with yielding ability. Treatments consisted of high, medium, and low populations (approximately 21, 13, and 3 plants per square meter) at 0.96‐m row widths and a medium population (approximately 13 plants m−2) at 0.43‐m row widths for 2 yr. The values of total dry matter (TDM), stem DM, leaf DM, leaf area, height, and main stem node number were determined on both a whole plant and ground area basis. In addition, relative growth rate (RGR), relative leaf area growth rate (RLAGR) and net assimilation rate (NAR) were examined. Treatments with the greatest interplant space had the largest RGR, RLAGR, and NAR early in growth, thus resulting in compensation for reduced plant population. Decreases in plant DM at 91 DAP in response to increasing plant population were greater in 1988 than in 1989, and were related to poorer growing conditions in the latter year. The related TDM values were larger in 1988, with all treatments exhibiting a TDM above 500 g m−2 by early podfill (R5). In contrast, the TDM at 91 DAP of the wide row, low and medium population treatments was 300 and 426 g m−2, respectively in 1989. Seed yield differences were found in 1989 but not 1988. Differences among years and treatments concerning growth rates, plant DM, TDM, and seed yield emphasize the impact of limiting environmental factors on plant compensation in response to increased space.}, number={1}, journal={AGRONOMY JOURNAL}, author={WELLS, R}, year={1993}, pages={44–48} }
 @article{wells_burton_kilen_1993, title={SOYBEAN GROWTH AND LIGHT INTERCEPTION - RESPONSE TO DIFFERING LEAF AND STEM MORPHOLOGY}, volume={33}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci1993.0011183X003300030020x}, abstractNote={Altered canopy light environments created by plant architectural changes may increase plant productivity. Two morphological traits in soybean [Glycine max (L.) Merr.], brachytic stems (shortened internodes) and lanceolate leaflets, could be used for genetic manipulation of canopy structure. These traits were examined in various combinations in ‘Tracy‐M’ (maturity group VI) and ‘Wright’ (maturity group VII) backgrounds in 1990 (two environments) and 1991 (one environment with two row width‐plant population combinations). Throughout the season, plant height and photosynthetically active radiation (PAR) interception were monitored. At maturity, stem dry weight, seed yield, and yield components were determined. Brachytic stem genotypes were ≈40% shorter at harvest than the normal genotypes. Plant height was significantly associated with PAR interception during vegetative grown in both years R2 ≥ 0.58), and during reproductive growth in wide rows at Clayton irrespective of year (R2 ≥ 0.66). In 1991, seed yield was positively related to PAR interception during reproductive growth in the wide row‐low population combination (r2 = 0.49), when all genotypes were included in the analysis. For the Tracy‐M background, the same relationship was significant in all widerow environments. The data indicate that brachytic genotypes do not fully intercept available PAR in wide rows and low populations, especially when combined with lanceolate leaflets. Significant seed yield differences, despite 95% PAR interception by all genotypes in some environments, indicate the presence of yield limiting factors other than PAR interception. The present data fail to indicate significant improvements in performance due to the brachytic stem or lanceolate leaflet.}, number={3}, journal={CROP SCIENCE}, author={WELLS, R and BURTON, JW and KILEN, TC}, year={1993}, pages={520–524} }
 @article{wells_bi_anderson_wynne_1991, title={PEANUT YIELD AS A RESULT OF 50 YEARS OF BREEDING}, volume={83}, ISSN={["0002-1962"]}, DOI={10.2134/agronj1991.00021962008300060007x}, abstractNote={AbstractBreeding for increased yield is known to indirectly alter other plant characteristics in many crop species, including peanut (Arachis hypogaea L.). This 2‐yr, field study examined growth and dry matter allocation to various plant organs of 10 Virginia‐type peanut genotypes bred for increased yield in North Carolina, Genotypes representing the period from 1944 to the present were grown in 1988 and 1989. Growth was measured on five dates in each year. Genotypes expressed as the minimum number of breeding cycles from an indigenous germplasm exhibited a yield increase of 30 g m2 per breeding cycle. Genotypes developed from a greater number of breeding cycles tended to have smaller vegetative mass and shorter main stem lengths. However, concurrent increases in reproductive allocation, measured as pod mass and reproductive‐to‐vegetative ratios (RVR), were evident. Correlation analysis at 133 d after planting (DAP) between the number of breeding cycles and measurements of main stem length, total dry weight (DW), vegetative DW, stem DW, leaf area index (LAI) and RVR resulted in significant correlation coefficients of −0.67,0.38, −0.67, −0.71, −0.42, and 0.74 respectively. At 71 DAP, reproductive growth, measured as peg number, pod number, pod mass, and RVR was correlated with the number of breeding cycles, with significant correlation coefficients of 0.53, 0.52, 0.46, and 0.46, respectively. Reproductive to vegetative ratio continued to be positively related to both breeding cycle number and year of cultivar release throughout reproductive growth. The data indicate greater reproductive dry matter allocation by more recently released genotypes. Further, the allocation in reproductive growth appears related to an earlier transition from vegetative to reproductive development}, number={6}, journal={AGRONOMY JOURNAL}, author={WELLS, R and BI, T and ANDERSON, WF and WYNNE, JC}, year={1991}, pages={957–961} }
 @article{wells_1991, title={SOYBEAN GROWTH-RESPONSE TO PLANT-DENSITY - RELATIONSHIPS AMONG CANOPY PHOTOSYNTHESIS, LEAF-AREA, AND LIGHT INTERCEPTION}, volume={31}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci1991.0011183X003100030044x}, abstractNote={Plant spacing greatly affects leaf area, light interception, and canopy apparent photosynthesis (CAP) in soybean [GLycine max (L.) Merr.]. This study examined relationships among these variables in four population‐density and row‐width treatment combinations for two seasons. Wide‐row (0.96 m) treatments were 3,11, and 18 plants m−2 in 1988 and 3, 15, and 24 in 1989; narrow‐row (0.43 m) treatments were 12 plants m−2 in 1988 and 13 in 1989. Narrow‐row treatments tended to have greater CAP rates during early growth in 1988, but not 1989, when rates lagged behind the wide‐row, high population. The reduction in CAP by the narrow‐row treatment in 1989 corresponded to its reduced light interception as measured parallel to the row base. Both total radiation (300‐2500 nm wavelengths) interception measured in 1988, and average photosynthetically active radiation (400‐700 nm) interception measured in 1989, were linearly related to CAP prior to, but not after, canopy closure. Similarly, leaf area indices (LAI) were curvilinearly related to percent light interception until canopy closure. After canopy closure, light interception did not decline at a rate commensurate with the loss of leaf area, indicating abscission of leaves not involved in light interception. Canopy photosynthesis was not different for any treatment after Reproductive Stage R5 in either year; however, significant differences were evident between Rl and R5 in 1989. These differences corresponded to the significantly lower yield of the low population in that year. Yield differences between the medium populations of the wide and narrow rows were not explained by CAP during reproductive growth. The data indicate that when LAI is above critical levels in post‐anthesis soybean canopies, factors other than photosynthesis may be involved in the response of seed yield to variation in plant density.}, number={3}, journal={CROP SCIENCE}, author={WELLS, R}, year={1991}, pages={755–761} }