Location: Coastal Plain Soil, Water and Plant Conservation Research
2021 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. The research consists of two studies initiated in 2019. The first part of this year’s update pertains to a field study designed to determine the impact of water deficit stress on fiber length development. Bolls were intensively sampled among a group of diverse genotypes in well watered and water deficit stress field plots every five days through the first 35 days of fiber development in 2019 and 2020 field trials. Fiber length measurements should be completed by the end of 2021 across the time series to develop fiber length growth curves for each genotype. This research supports Subobjective 1A of the project plan to identify genotypes with fiber length stability when subject to water deficit stress during fiber elongation. The second, 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 and data is currently being analyzed. The cotton experiment, which featured two genotypes differing in rooting ability (deep and shallow), was initiated in 2021 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 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 used to produce an aviation biofuel for jet engines. Carinata also provides a source of protein meal for animal feed. In 2021, as part of the USDA-NIFA Coordinated Agricultural Project ‘Southeast partnership for advanced renewables from carinata-SPARC’, the fourth 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, and 2021 demonstrate the potential for carinata production in the northern region of the southeast USA. In addition, the first year of a two-year study to evaluate the potential of carinata as a cover crop and/or double crop with cotton was completed in 2020. Data collected in 2020 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. In cooperation with NuSeed Americas Inc., a second carinata-cotton cropping system research project was initiated in 2021 to directly compare a carinata-cotton double crop system to winter wheat-cotton and fallow-cotton systems. 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. In 2020, data collected in a multi-year and -location study (Florence, South Carolina, Maricopa, Arizona, and College Station, Texas) was used as the basis to officially release five germplasm lines with 50% exotic landrace parentage that display excellent agronomic and fiber quality performance. The release of these five germplasm lines provides the cotton industry much needed sources of high yield and fiber quality with new genetic diversity. Following a seed increase in 2021, seed of these five 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 further 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 new breeding stock containing previously untapped and valuable genetic diversity.
Accomplishments
1. Release of high yield and high fiber quality germplasm lines containing 50% exotic parentage. New genetic diversity is desperately needed to broaden the genetic base while also improving the economic competitiveness of U.S. cotton. Upland cotton’s narrow genetic diversity represents a major source of genetic vulnerability for the U.S. cotton industry. To address this genetic vulnerability, ARS researchers in Florence, South Carolina, College Station, Texas, and Maricopa, Arizona, in partnership with Cotton Incorporated and Clemson University, released five high yield and fiber quality germplasm derived from exotic lines originally from Asia, Africa, and South America accessions. The research showed that each new cotton line possesses 50% exotic parentage, excellent fiber quality, and excellent yield performance—significantly better than several commercial cultivars. These results provide public and private breeding firms a set of new, elite germplasm lines that can be used as breeding parents to develop new commercial cultivars with increased genetic diversity.
2. Documenting the genetic structure of the Pee Dee cotton breeding program. Understanding the landscape and organization of genetic diversity in a breeding program is critical to best formulate future breeding goals and strategies. In partnership with Clemson University, ARS researchers in Florence, South Carolina, and Raleigh, North Carolina, conducted a detailed genetic survey of the program’s eight historical breeding cycles and found that 99% of the total genetic variation was incorporated within the first four breeding cycles. The research showed that a small core collection of eleven lines captured 95% of the program’s genetic diversity. The research also identified genetic signatures differentiating the Pee Dee breeding program relative to other improved upland cotton germplasm across the world. Collectively, this information will be used to set future Pee Dee breeding program goals and directions. These results provide public and private breeding programs critical knowledge for bringing new, genomic assisted methods to cotton breeding that hold great promise to revolutionize cotton improvement.
Review Publications
Billman, E.D., Morrison, J.I., Baldwin, B.S. 2021. Breeding heat tolerant orchardgrass germplasm for summer persistence in high temperature stress environments of the southeastern United States. Crop Science. https://doi.org/10.1002/csc2.20492.
Campbell, B.T. 2021. Examining the relationship between agronomic performance and fiber quality in ten cotton breeding populations. Crop Science. 61:989-1001. https://doi.org/10.1002/csc2.20370.
Campbell, B.T., Hinze, L.L., Thompson, A.L., Jones, M., Jones, D. 2021. Registration of PD 20170048, PD 20170049, PD 20170050, PD 20170053, and PD 20170054 germplasm lines of cotton. Journal of Plant Registrations. https://doi.org/10.1002/plr2.20128.
St Aime, R., Rhodes, G., Jones, M., Campbell, B.T., Narayanan, S. 2021. Evaluation of root traits and water use efficiency of different cotton genotypes in the presence or absence of a soil-hardpan. The Crop Journal. https://doi.org/10.1016/j.cj.2020.12.001.
Holladay, S., Bridges, W., Jones, M., Campbell, B.T. 2021. Yield performance and fiber quality of pima cotton grown in the southeast United States. Crop Science. https://doi.org/10.1002/csc2.20505.
Billings, G., Jones, M., Rustgi, S., Hulse-Kemp, A.M., Campbell, B.T. 2021. Population structure and genetic diversity of the Pee Dee cotton breeding program. Genes, Genomes, Genetics. https://doi.org/10.1093/g3journal/jkab145.
Barnes, E.M., Campbell, B.T., Vellidis, G., Porter, W., Payero, J., Leib, B., Sui, R., Fisher, D.K., Anapalli, S.S., Colaizzi, P.D., Bordovsky, J., Porter, D., Ale, S., Mahan, J.R., Taghvaeian, S., Thorp, K.R. 2020. Forty years of increasing cotton’s water productivity and why the trend will continue. Applied Engineering in Agriculture. 36(4):457-478. https://doi.org/10.13031/aea.13911.
