Location: Coastal Plain Soil, Water and Plant Conservation Research
2022 Annual Report
Objectives
Objective 1. Determine the ability of cotton germplasm to withstand soil water deficits, identify and characterize drought tolerance genes, and develop innovative management practices for optimizing use of the improved genotypes in production systems.
Sub-objective 1A. Identify genotypes with fiber length stability when subject to water deficit stress during fiber elongation.
Sub-objective 1B. Identify cotton genotypes that withstand soil water deficits.
Sub-objective 1C. Evaluate variable rate irrigation using crop feedback for site-specific irrigation management of cotton in the Southeastern U.S. Coastal Plain.
Objective 2. Develop and evaluate new cotton germplasm with increased genetic diversity, improved fiber quality, and lint yield stability traits.
Approach
New technologies and new genetic resources are needed to help the nation’s cotton producers face increasing economic and environmental challenges. The proposed research will contribute to the industry’s ability to meet the nation’s fiber needs and become more competitive in world markets. Since water deficit stress is a serious limitation to cotton production, much of this research will be aimed at finding solutions to lessen the impact of this environmental stress. The research has two objectives: (1) determine the ability of cotton germplasm to withstand soil water deficits, identify and characterize genetic variation for drought tolerance, and develop innovative management practices; and (2) develop new cotton genetic resources with increased genetic diversity, improved fiber quality, and lint yield stability. In this research, we will conduct genetic studies on the effect of water deficit stress on fiber length and yield, determine how best to use proximal sensing data collected from high throughput phenotyping platforms, design innovative double crop cotton production systems, and develop new cotton genetic resources. Research methods include field experiments and statistical analyses using modern analytical equipment and innovative analytics. Research products include new knowledge of genetic variation for fiber length stability under water deficit stress, protocols for using proximal sensing data collected from high throughput phenotyping platforms as a water deficit stress breeding selection tool, new water efficient cotton cropping systems, and high quality cotton germplasm containing exotic introgression. All segments of the cotton industry and southern rural economies will benefit from the findings of this research.
Progress Report
Water deficit stress research. A two-part field study is ongoing to determine if canopy temperature can be used to determine genotypic differences in drought tolerance for soybean (Part 1) and cotton (Part 2). For both soybean and cotton, intense canopy temperature data collection was initiated in a field trial consisting of two genotypes differing in their drought tolerance to determine soil water levels, crop growth stage, and local weather conditions which provide the best opportunity to differentiate genotypes differing in drought tolerance. The soybean experiment, which featured two genotypes differing in canopy wilting (slow and fast), was completed in 2020. A manuscript describing the results of the experiment is currently being drafted. The cotton experiment, which features two genotypes differing in rooting ability (deep and shallow), was initiated in 2021. Canopy temperature data was collected in the 2021 field experiment and is currently being analyzed. An additional field experiment was initiated in 2022 to collect the second year of data, and canopy temperature data is currently being collected. This research supports Subobjective 1B of the project plan to identify cotton genotypes that withstand soil water deficits.
Cotton-Carinata cropping system research. Research was initiated in 2018 to evaluate Brassica carinata (carinata) as a winter cash cover crop in rotation with cotton. Carinata is a multi-use oilseed crop to produce an aviation biofuel for jet engines. Carinata also provides a source of protein meal for animal feed. In 2022, as part of the USDA-NIFA Coordinated Agricultural Project ‘Southeast partnership for advanced renewables from carinata-SPARC’, the fifth year of carinata breeding line evaluations was conducted in Florence, South Carolina. Although the 2018 field trial sustained significant freeze damage that resulted in 100% plant death, results in 2019, 2020, 2021, and 2022 demonstrate the potential for carinata production in the northern region of the southeast USA. In addition, a two-year study to evaluate the potential of carinata as a cover crop and/or double crop with cotton was completed in 2021. Data collected in 2020 and 2021 demonstrated that cotton following carinata had greater lint yields than cotton following wheat or fallow. This was attributed to greater boll density in carinata-cotton systems than wheat-cotton or fallow-cotton, with more prevalent secondary and tertiary bolls per plant. Collectively, this research supports Subobjective 1C of the project plan to develop innovative management practices for optimizing production systems by determining the feasibility of carinata as a new part of the cotton production system in the northern southeast U.S.
Cotton germplasm development research. Data collected over the last five years in a multi-location study (Florence, South Carolina, Maricopa, Arizona, and College Station, Texas) was used to officially release ten germplasm lines with 50% exotic landrace parentage that display excellent agronomic and fiber quality performance. The release of these ten germplasm lines provides the cotton industry much-needed sources of high yield and fiber quality with new genetic diversity. Following a seed increase in 2022, the seed of these germplasm lines will be provided to private and public breeding programs as a source of new breeding parents. To our knowledge, this is the first release of elite germplasm containing 50% exotic landrace parentage. Also, a project to develop exotic introgression populations containing different levels of exotic introgression is ongoing. Exotic lineages of 25%, 50%, and 75% are being advanced. The introgression populations developed by the end of this project plan will provide a rich genetic resource to study exotic landrace introgression in cotton. Together, this research supports Objective 2 of the project plan to develop and evaluate new cotton germplasm that will provide the cotton industry with new breeding stock containing previously untapped and valuable genetic diversity.
Accomplishments
1. Overcoming the negative relationship between yield and cotton fiber quality. Future cotton production systems need cultivars with improved fiber quality to meet global market demands and provide the textile industry with high-quality fiber. However, developing cotton cultivars with high yield potential and premium fiber quality has been a major bottleneck because of the negative relationship between yield and cotton fiber quality. To address this bottleneck, ARS researchers in Florence, South Carolina, evaluated the relationship between yield and fiber quality in several large, breeding populations developed using cotton breeding lines with both high yield and premium fiber quality potential as breeding parents. The research showed that the frequency of high yield/high fiber quality offspring was more significant in populations using parents with high yield and fiber quality. Moreover, the research demonstrated that the frequency of identifying high yield/high quality offspring in these populations remained extremely low-generally less than 3%. These results provide critical information that can be used to design breeding methods that simultaneously improve yield and cotton fiber quality.
2. Bringing high-value Pima cotton production to the southeast United States. Current southeast U.S. cotton production systems include the production of upland cotton only, while Pima cotton production is restricted to arid regions of the western U.S. Due to its increased value relative to upland cotton, Pima cotton offers an attractive alternative crop for southeast U.S. producers. In partnership with Clemson University, ARS researchers in Florence, South Carolina, evaluated the yield performance and fiber quality of Pima cotton grown in the southeast U.S. The research showed that Pima cotton produced premium fiber quality compared to upland cotton but yielded 50% less. Although the net economic return of the highest-yielding Pima lines was not different from upland cotton, the research demonstrates that new Pima cultivars with adaptation to the southeast U.S. are needed to offset the current reduction in yield potential. These results provide critical information that can be used to evaluate the feasibility of commercial Pima cotton production in the southeast region of U.S.
Review Publications
Yu, J., Jung, S., Cheng, C., Lee, T., Zheng, P., Buble, K., Crabb, J., Humann, J., Hough, H., Jones, D., Campbell, B.T., Udall, J.A., Main, D. 2021. CottonGen: the community database for cotton genomics, genetics, and breeding research . Plants. 10(12):2805. https://doi.org/10.3390/plants10122805.
Holladay, S., Bridges, W., Jones, M., Campbell, B.T. 2022. Growth, boll development, agronomic performance, and fiber quality of Gossypium Barbadense L. in the Southeast US Coastal Plain. Crop Science. (62):1461-1471. https://doi.org/10.1002/csc2.20756.
