AGRONOMIC PRACTICES AND MANAGEMENT SYSTEMS FOR OPTIMUM COTTON PRODUCTIVITY AND PROFITABILITY IN SOUTH CAROLINA

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1018218
• Project Start Date: Nov 7, 2018
• Project End Date: Sep 30, 2022
• Program Code: [(N/A)]- (N/A)

Recipient Organization
CLEMSON UNIVERSITY
(N/A)
CLEMSON,SC 29634

Performing Department
Plant & Environmental Sciences

Non Technical Summary
Cotton Variety Selection and Evaluation. Making proper variety selection decisions is often the first and potentially the most important management decision growers make each growing season. Although seed companies and breeders have done a great job of continually releasing new, high-yielding, high quality varieties to the market each year, it is up to cotton growers to do their homework to make sure the varieties they are planting on their farms each year are adapted to their area and are the most profitable for them to grow. Based on research data from most university variety trials, it is not uncommon for lint yield differences between the highest yielding variety and the lowest yielding variety in these trials to be 500 to 700 lb/acre. This difference in yield is money lost to growers before the seed is even put in the ground, and shows the importance of making good variety choices. The development and release of new cotton varieties by seed companies throughout the U.S. Cotton Belt greatly accelerated during the late 1990's and early 2000's with the development and release of transgenic technologies such as Bollgard, Roundup-Ready, and Liberty-Link cotton. Today, this trend is currently accelerating even more due to the release of new transgenic technologies such as Bollgard II and III, Roundup-Ready Flex, Widestrike and Widestrike 3, Glytol, Dicamba, and 2,4-D resistant cottons. These new varieties are now offered for sale with fewer years of public testing than most growers, consultants, and university personnel need for proper evaluation. Increasing the number of locations within a given year that a new variety is evaluated will expose the cotton variety to as many different growing conditions, management inputs, soil types, and environmental stresses as possible, and hopefully expose any problems associated with the performance of a variety before it reaches commercial fieldsAdaptation/Incorporation of New Transgenic Technologies into Current Cotton Production Systems. Glyphosate-resistant weed biotypes have developed over the past few decades due to intense selection pressure through widespread use of glyphosate and the adoption of monoculture production systems which rely on glyphosate-tolerant varieties. Glyphosate-resistant Palmer amaranth (Amaranthus palmeri S. Wats) was first discovered in Georgia in 2005 (Culpepper et al., 2009). Since its initial discovery, populations of glyphosate-resistant Palmer amaranth have been reported in most major cotton producing states in the southeastern U.S. (Wallace et al., 2011). Control of glyphosate-resistant Palmer amaranth is of upmost concern to cotton producers because of its potential to reduce yields, increase production costs, and interfere with mechanical harvest (Culpepper et al., 2009; Whitaker et al., 2011). The development and spread of glyphosate-resistant Palmer Amaranth and other weed species has forced many growers and private industry alike to seek out alternative weed control methods. Several new cotton germplasm technologies that allow alternative herbicide modes of action have recently been developed, registered, and released to the cotton industry. New transgenic cottons such as Glufosinate-tolerant cotton (Liberty-Link, Widestrike and Widestrike 3, and Roundup-Ready Xtend varieties), Dicamba-tolerant cotton (Roundup Ready Xtend varieties), and 2,4-D tolerant cotton (Enlist varieties) are now planted on a large percentage of the cotton acres in the U.S.Response of Cotton Varieties to Irrigation in the Southeastern Coastal Plains. Responses from 885 cotton growers in the 2011 Producer Priority Survey conducted by Cotton Incorporated indicated that water was the number one 'top-of-mind' concern producers had about cotton production. Comments ranged from needing more drought resistant varieties to how water effects yield stability from year to year. Additionally, cotton tolerance to heat and drought was ranked as the number four 'Key Issue' that should be addressed by research funding. In response to this survey research focusing on the response of current experimental (pre-commercial release) cotton varieties was initiated. Similar research reported at the Beltwide Cotton Conferences by Main et al. (2012) addressed response of commercial cotton varieties to irrigation. Results of these trials indicate that cotton variety response to water is highly variable in humid, rain-fed growing areas. As variety offerings change on almost an annual basis with changes in technological traits, growers are often unsure of how a new variety may respond to irrigation. Previous research provides a framework for current research procedures. During vegetative growth, root growth out paces shoot growth leading to very little potential for water stress. However, high yield potential requires stress avoidance during pre-bloom construction of vegetative framework. Stress during the pre-bloom period is most detrimental due to a reduction in the number of fruiting sites and less photosynthetic surface to retain mature bolls (Hake and Grimes, 2010). In addition, moisture stress during peak bloom can reduce yield (Grimes et al., 1970). Research from Logenecker and Erie (1968) suggests that seed index (seed size) is more sensitive to moisture stress than staple and micronaire. Although, micronaire can be reduced if drought stress occurs during secondary cell wall thickening (Hake and Grimes, 2010) Furthermore, droughty periods reduce fiber length and adequate water increases fiber length. (Jordan,1982). These results are consistent with the current research of Main et al. (2012). Therefore, investigation of experimental cotton variety response to water is a critical research need that can be addressed through continued investigations.

Animal Health Component

100%

Research Effort Categories

Basic

(N/A)

Applied

100%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
205	1710	1020	100%

Knowledge Area
205 - Plant Management Systems;

Subject Of Investigation
1710 - Upland cotton;

Field Of Science
1020 - Physiology;

Keywords

cotton, management systems

lint yield, fiber quality

variety testing

irrigation

Goals / Objectives
1. To increase the number of environments within a given year that newly released cotton cultivars are evaluated in order to help growers make sound decisions with cultivar selection, to compare the performance of newer cultivars to older established cultivars, and to assess the differences in yield, maturity and fiber quality among newly developed transgenic siblings and their recurrent parents.2. To determine how, when, and at what rates these new herbicides should be applied, how to manage and incorporate these new technologies into a whole farm system and/or a farm community system, if these new transgenic varieties will be adapted to growing conditions in South Carolina, and if so, do differences in tolerance levels of these new transgenic varieties exist.3. To evaluate experimental and commercial cotton varieties for lint yield and fiber quality response to irrigation4. To assess plant growth regulator effects on cotton plant growth and development, lint quantity/quality, and profitability in South Carolina.5. To determine the efficacy, optimum timing, and environmental interactions associated with proper harvest-aid applications in South Carolina cotton; to determine the time (based on heat units) required for various bolls located on the plant to open after boll openers are applied; and to assess changes in boll development and fiber properties at various fruiting positions in response to premature defoliation and boll opening.

Project Methods
Twenty-to-thirty replicated field studies will be conducted annually at the Pee Dee and Edisto Research and Education Centers, as well as at on-farm locations representative of the environments in which cotton is produced statewide. Studies will involve the evaluation of varieties, herbicide systems, plant growth regulators, harvest-aid materials, seed- or soil-applied insecticides/nematicides, and agronomic practices such as plant density, planting date, tillage systems, and irrigation. Treatments may include commercially-available and/or experimental varieties and chemicals appropriate for the region. Chemical treatments may involve multiple applications based on cotton growth stage, plant growth monitoring, and climatic conditions. Ultimately, chemical treatments will involve a cost-effectiveness evaluation, which will take into account chemical and application costs, as well as lint yields and/or fiber quality. Agricultural economists on the faculty of Clemson University will be consulted as needed for economic aspects of the project.Trials will predominantly involve the use of small plots (4 to 8 rows, 30 to 38 inch row width, X 30 to 50 feet in length), although large plots (8 to 36 rows X 100 to 1000 feet in length) will be utilized for commercially-available treatments where possible. Four to six replicates will be used for each experiment. Production practices and pest management will follow those recommended by the Clemson University Cooperative Extension Service. At on-farm test sites, the producers' management practices will be followed. Data collected will include stand counts, early-season plant growth (e.g., plant height, total nodes, square retention, and total fruit), mid-season growth parameters (e.g., weekly white bloom counts, nodes above first-position white flower, height-to-node ratio, fruit retention, and percent bolls), as well as parameters aimed at timing harvest-aid chemicals and measuring maturity differences (nodes above highest cracked boll and percent open bolls). Crop yield will be determined (seed cotton, lint and seed yields), fifty boll sub-samples will be used to assess changes in yield components (boll size, % lint, seed index), and fiber quality will be determined using High Volume Instrumentation and/or stelometer (when only fiber strength is needed) technology. Where appropriate, leaf area indices and plant biomass accumulation will be determined, which will allow changes in plant dry matter partitioning to be determined, as well as changes in relative maturity levels and boll development.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:South Carolina and U.S. cotton producers across the Cotton Belt; South Carolina and U.S. County Extension personnel; South Carolina and U.S. cotton consultants and scouts; South Carolina and U.S. cotton commodity associations; South Carolina and U.S. cotton grower organizations; State Agencies, agribusinesses such as seed and chemical companies; University and USDA researchers and extension personnel. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Two Master's theses were produced by Sarah Holladay and Grant Billings based on the project. Evaluation was provided by the graduate committee. These students developed oral and written communication skills through communications of results based on the project. Information from this project was presented at field days, in newsletters,in the growers' guide, and at extension meetings. How have the results been disseminated to communities of interest?Through this research, information on cotton management issues in South Carolina were improved in terms of both yield response and profitability. In most cases, refining application systems for agri-chemicals enabled less product usage to produce the same or better performance. This usually translated into a cost-savings to the producer. Other impacts where seen in terms of cotton quality. Many of the products' rates and timings, especially the harvest-aid materials, affected fiber quality significantly. Likewise, management of time from application of these materials to potential harvest date improved such that timing of chemical application was better coordinated with a particular producer's harvest schedule and capacity. This led to not only an improvement in quality factors due to less unnecessary weathering between defoliation and harvest, but also increases in yield due to less loss from weathering. These studies were included in several state-level field tours. Results were presented at the South Carolina State Cotton meeting, ASA meetings, Beltwide Cotton Conferences, and numerous county production meetings. Articles were published in popular farming magazines. Multi-year results were published in refereed scientific journals. Data and results were used to establish, supplement, demonstrate, or verify Extension recommendations. What do you plan to do during the next reporting period to accomplish the goals?Numerous replicated field experiments will be conducted at the Pee Dee Research and Education Center in Florence, SC, at the Edisto Research and Education Center in Blackville, SC, and at numerous on-farm locations in upcoming year in order to meet the objectives and goals of this research project. Data and results will continue to be disseminated through appropriate available formats such as field days, local, state, and national meetings, and through publication in scientific journals and meeting proceedings. Extension recommendations will be updated based on results as needed.

Impacts
What was accomplished under these goals? The development and release of new cotton varieties by seed companies throughout the U.S. Cotton Belt has greatly accelerated since the development of transgenic technologies such as Bollgard II and III, Roundup-Ready Flex, Widestrike and Widestrike 3, and Liberty-Link cottons. This trend continues to accelerate with the release of new transgenic technologies such as TwinLink, Glytol, 2,4-D-tolerant and Dicamba-tolerant cottons. Unfortunately for growers, the incorporation of these transgenic traits into newer conventional varieties often changes the growth and development of the transgenic siblings compared to the conventional parent. These new cultivars are now offered for sale with fewer years of public testing than most growers, consultants, and university personnel need for proper evaluation. Each state conducts "official variety trials" to evaluate new varieties for yield and quality. However, South Carolina is limited in the number of locations within a given year to evaluate these new varieties. One way to increase the number of environments or evaluations of a new cultivar is to increase the number of locations within a given year. Increasing the number of locations within a given year will expose a new cotton cultivar to as many different growing conditions, management inputs, soil types, and environmental stresses as possible, and hopefully expose any problems associated with the performance of a cultivar before it reaches growers' fields. Replicated cultivar trials were planned at 4 locations throughout South Carolina at grower's farms. Only one of these locations was harvested due to poor environmental conditions during the 2020 growing season. These trials were in addition to the Official Variety Trials conducted at the Pee Dee REC and Edisto REC locations. Trial locations were conducted on growers' farms and each trial consisted of between 30 to 40 cultivars. Trial locations were selected based on previous and projected cotton acreage in a given area and differences in soil types and management inputs. An effort was made to evaluate cultivars under as many different environments as possible within areas of high cotton acreage. New cultivars were chosen based on projected planted acreage in the state and the potential for the cultivar to perform in South Carolina. Trials were located in areas of high visibility and marked with signs so growers can evaluate cultivars throughout the season. Information from these trials was presented at field days, in newsletters and in the growers' guide, and at extension meetings. In the United States, pima cotton is currently only produced in California, Arizona, New Mexico and Texas and accounts for only 3% of the total cotton production in the country, with the other 97% being upland cotton. Pima has longer, stronger, finer, and more uniform fibers than the more commonly grown upland cotton, making it considerably more valuable. The goal of this research was to determine if pima production could be successful in South Carolina, further boosting the economic impact cotton has on the state. The main objectives of this study were to (1) identify pima genotypes that have acceptable yield and fiber quality when ginned by two different types of cotton gins, and (2) to determine if irrigation would be needed in order to cultivate the crop in South Carolina. In the second objective, pima genotypes were also planted on three different planting dates (Late-April, Mid-May, and Late-May) in order to determine how early it should be planted to accommodate for its longer growing season. The pima genotypes were compared to upland checks in both trials for yield, fiber quality, and plant physiology. In both trials the upland checks yielded significantly higher than the pima genotypes; however, the pima genotypes had significantly better fiber quality. The top five pima genotypes had statistically similar net return values when priced at the respective base loan rates for pima ($0.95/lb) and upland ($0.52/lb) cotton. Irrigation had no significant impact on lint yield in either year of the study and planting date only had a significant impact in 2019 with the early date producing more yield than the other two dates. With yields being fairly low, it is difficult to determine whether or not pima would be successful in South Carolina without further research.

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Plumblee, M.T., Kirk, K., Jones, M.A., Crouch, A, Davis, C., and Croft, J. 2020. Precision Agriculture: Cotton Picker Yield Monitor Calibration. Land-Grant Press (1057). Igpress.clemson.edu
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2020 Citation: Billings, G.T., M.A. Jones, W.C. Bridges, A.M. Hulse-Kemp. and B.T. Campbell. 2020. Genetic Evaluation of Cotton Breeding Resources from the Pee Dee Germplasm Enhancement Program. pp. 294. Proc. Beltwide Cotton Conf.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2020 Citation: Holladay, S.K., M.A. Jones, and B.T. Campbell. 2020. Identifying Accessions and Management Practices for the Production of Pima Cotton in South Carolina. Proc. Beltwide Cotton Conf.

Progress 11/07/18 to 09/30/19

Outputs
Target Audience:South Carolina and U.S. cotton producers across the Cotton Belt; South Carolina and U.S. County Extension personnel; South Carolina and U.S. cotton consultants and scouts; South Carolina and U.S. cotton commodity associations; South Carolina and U.S. cotton grower organizations; State Agencies, agribusinesses such as seed and chemical companies; University and USDA researchers and extension personnel. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?According to the USDA-AMS Varieties Planted publication, South Carolina cotton growers planted approximately 72% of the total cotton acreage in state between 2004 and 2009 to varieties which ranked in the top 10 in lint yield in Clemson University replicated variety trials. This is a significant statistic and shows the positive impact of the enhanced variety testing program and the information collected by this research project and the immediate grower response to educational efforts by Clemson Extension personnel in relaying this information. In 1999, 2000, 2001, and 2002, South Carolina cotton growers only planted 0.4, 10, 4, and 22% of the state's cotton acres to the highest yielding varieties in Clemson University variety trials, respectively. Due to the loss of a popular, high-yielding adapted Bollgard cotton variety to company non-re-registration in 2009, South Carolina cotton growers were once again trying to determine which varieties to plant on their farms. In 2010, the loss of Bollgard technology in the U.S. and the resulting loss of this popular Bollgard variety caused a significant decrease in the percentage of high yielding varieties planted in South Carolina (declined to only 42%). Due to increased variety testing, this percentage rebounded in 2011 to 2019, with 75% of our acreage planted to high-yielding varieties. Planting the best varieties, coupled with good environmental conditions and improved management practices, resulted in a record cotton crop in 2012 with a state average of 955 lbs of lint/acre and 912 lb of lint/acre in 2017. Moreover, average cotton lint yields in South Carolina from 1980 to 2019 have increased from approximately one bale per acre to almost two bales per acre over this 40 year time frame. This is an increase in South Carolina lint yields of almost nine pounds of lint per acre per year, and shows the tremendous positive impact that cotton research programs like this one have made and hopefully will continue to make on the lives of South Carolina cotton farmers and citizens. How have the results been disseminated to communities of interest?Through this research, information on cotton management issues in South Carolina were improved in terms of both yield response and profitability. In most cases, refining application systems for agri-chemicals enabled less product usage to produce the same or better performance. This usually translated into a cost-savings to the producer. Other impacts where seen in terms of cotton quality. Many of the products' rates and timings, especially the harvest-aid materials, affected fiber quality significantly. Likewise, management of time from application of these materials to potential harvest date improved such that timing of chemical application was better coordinated with a particular producer's harvest schedule and capacity. This led to not only an improvement in quality factors due to less unnecessary weathering between defoliation and harvest, but also increases in yield due to less loss from weathering. These studies were included in several state-level field tours. Results were presented at the South Carolina State Cotton meeting, ASA meetings, Beltwide Cotton Conferences, and numerous county production meetings. Articles were published in popular farming magazines. Multi-year results were published in refereed scientific journals. Data and results were used to establish, supplement, demonstrate, or verify Extension recommendations. What do you plan to do during the next reporting period to accomplish the goals?Numerous replicated field experiments will be conducted at the Pee Dee Research and Education Center in Florence, SC, at the Edisto Research and Education Center in Blackville, SC, and at numerous on-farm locations in upcoming year in order to meet the objectives and goals of this research project. Data and results will continue to be disseminated through appropriate available formats such as field days, local, state, and national meetings, and through publication in scientific journals and meeting proceedings. Extension recommendations will be updated based on results as needed.

Impacts
What was accomplished under these goals? The development and release of new cotton varieties by seed companies throughout the U.S. Cotton Belt has greatly accelerated since the development of transgenic technologies such as Bollgard II and III, Roundup-Ready Flex, Widestrike and Widestrike 3, and Liberty-Link cottons. This trend continues to accelerate with the release of new transgenic technologies such as TwinLink, Glytol, 2,4-D-tolerant and Dicamba-tolerant cottons. Unfortunately for growers, the incorporation of these transgenic traits into newer conventional varieties often changes the growth and development of the transgenic siblings compared to the conventional parent. These new cultivars are now offered for sale with fewer years of public testing than most growers, consultants, and university personnel need for proper evaluation. Each state conducts "official variety trials" to evaluate new varieties for yield and quality. However, South Carolina is limited in the number of locations within a given year to evaluate these new varieties. One way to increase the number of environments or evaluations of a new cultivar is to increase the number of locations within a given year. Increasing the number of locations within a given year will expose a new cotton cultivar to as many different growing conditions, management inputs, soil types, and environmental stresses as possible, and hopefully expose any problems associated with the performance of a cultivar before it reaches growers' fields. Replicated cultivar trials were conducted at 4 locations throughout South Carolina at grower's farms. These trials were in addition to the Official Variety Trials conducted at the Pee Dee REC and Edisto REC locations. Trial locations were conducted on growers' farms and each trial consisted of between 30 to 40 cultivars. Trial locations were selected based on previous and projected cotton acreage in a given area and differences in soil types and management inputs. An effort was made to evaluate cultivars under as many different environments as possible within areas of high cotton acreage. New cultivars were chosen based on projected planted acreage in the state and the potential for the cultivar to perform in South Carolina. Trials were located in areas of high visibility and marked with signs so growers can evaluate cultivars throughout the season. Information from these trials was mailed to each cotton grower in the state and was also presented at field days, in newsletters and in the growers' guide, and at extension meetings. Historical data from the USDA Ag Statistics Service has shown that U.S. cotton yields increased nationally almost 9 to 10 lbs/acre/year over the past 50 years, with most of this yield increase credited to plant breeding programs selecting for increased lint production. Most of this increase in lint yield production has been attributed to changes in the reproductive growth and development of cotton varieties over time, with apparent increases in boll numbers and lint percentages and decreases in boll size and seed size. Moreover, yield increases since the early 1980's have coincided with improved fiber quality parameters such as fiber length and strength. Historical data from South Carolina has shown similar trends, with cotton lint yields increasing over the past 150 years in the 4 to 5 lb/acre/year range. A study conducted by Wells and Meredith in the early-1980's found that more modern varieties (1970's) made an earlier transition from vegetative growth to reproductive growth and partitioned more dry matter into reproductive organs compared to older lower yielding varieties. This earlier transition from vegetative growth to reproductive growth occurred during a time when maximal leaf development was present and led to a greater harvest index and increased yields. The objective of this study was to determine what differences in vegetative/reproductive growth, fruiting characteristics, and lint quantity/quality associations have occurred over time as a result of selection for increased yield. Fourteen cotton varieties representing various decades (1900's to 2016) of release from the Stoneville and Deltapine lineage were planted in a randomized complete block design with four replications at the Pee Dee REC located in Florence, SC and at the Sandhills REC located in Columbia, SCduring the 2016 , 2017, and 2018 growing seasons. Plots consisted of four rows, 40 feet in length. Vegetative growth was monitored at various times during the season via leaf dry weights, stem dry weights, specific leaf weights, and leaf area indexes. Reproductive growth was also monitored by both number and dry weights of squares, flowers, and bolls. Plots were harvested with spindle type cotton pickers modified for small plot research. A seed cotton grab sample was collected from each plot, air dried, weighed and ginned. A subsample of lint was also collected for HVI fiber quality analysis. SC location: Preliminary results showed three distinct yield environments existed at the Florence location during the 2016, 2017, and 2018 growing seasons, with average lint yields of 627, 1178, and 1260 lb/a, respectively. The highest yielding varieties each year were the new transgenic varieties ST 4946GLB2 (880 lb/a in 2016, 1545 lb/a in 2017, and 1361 lb/a in 2018), DP 1252B2RF (827 lb/a in 2016, 1509 lb/a in 2017, and 1436 lb/a in 2018), and DP 1137B2RF (759 lb/a in 2016, 1250 lb/a in 2017, and 1556 lb/a in 2018). Large differences in yield were found among the varieties based on year of release, with varieties released after year 2000 having the highest yields (average yield of 780 lb/a in 2016, 1371 lb/a in 2017 and 1400 lb/a in 2018). Varieties released before 1965 had the lowest yields, averaging 470 lb/a in 2016, 947 lb/a in 2017, and 1010 lb/a in 2018. In all three years, a positive linear relationship was found between lint yield and year of release, with lint yields increasing 3.7 lb/a/year (R2= 0.74) in 2016, 5.0 lb/a/year (R2= 0.69) in 2017, and 4.7 lb/a/year (R2= 0.76) in 2018. Gin turnout was also affected by year of release, with newer varieties (after 2000) averaging 42% over all three years, varieties released between 1965 and 1999 averaging 39% lint, and varieties released before 1965 averaging 37% lint. Differences among varieties were also found with fiber quality, with newer varieties (released after 2000) appearing to have longer fibers (1.08 to 1.22 range) and higher micronaire values (3.7 to 4.6) compared to varieties released before 1965 (fiber lengths of 0.98 to 1.17 range) and lower micronaire values (3.6 to 4.6).

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Jones, M.A and R. Wells. 2019. Changes in Boll Development, Yield, and Fiber Quality of Commercial Varieties Over Time Based on Date of Release. Proc. of Beltwide Cotton Conferences. pp. 195 to 197.