Recipient Organization
TENNESSEE TECHNOLOGICAL UNIVERSITY
BOX 5033
COOKEVILLE,TN 38505
Performing Department
(N/A)
Non Technical Summary
The U.S. Upland cotton production has shifted to crop management systems based on genetically engineered (GE) cultivars since the 2000s. It has been faced with many challenges, including the decrease in planting area, high percentage crop failure, high technology fees, and damaging secondary insects and diseases. The urgent need from the cotton producer for productivity, profitability and sustainability has called solutions from public breeders using natural genetic variation. However, the genetic diversity within Upland cotton is very low, and exclusive intraspecific crossbreeding to develop GE cotton has limited the genetic gain in breeding. This proposal is based on our more than 30 years of extra-large population- based extensive efforts in introgression breeding between Upland and Pima cotton. The goal is to bring our introgression breeding to fruition in developing super green cotton (SGC) cultivars with novel natural genetic sources and breakthroughs for high-yielding, excellent fiber quality, and resistance/tolerance to abiotic and biotic stresses. SGC is cotton with the above desirable traits developed from utilization of natural genetic variation for green agriculture using less chemicals and water. We will publicly release 1-2 transgressive Upland cotton cultivars with high lint yield, high levels of drought tolerance, and resistance to seedling damping-off. We will also publicly release 1-2 Upland cotton cultivars with long, strong and fine fibers, and resistance to Verticillium wilt, Fusarium wilt race 4, spider mites, and thrips transferred from Pima cotton.
Animal Health Component
100%
Research Effort Categories
Basic
0%
Applied
100%
Developmental
0%
Goals / Objectives
The goal is to employ introgression breeding to develop super green cotton (SGC) cultivars with novel natural genetic sources and breakthroughs for high-yielding, excellent fiber quality, and resistance/tolerance to abiotic and biotic stresses. Here, we define SGC as cotton with the above desirable traits developed from utilizing natural genetic variation for green agriculture using less chemicals and water. The specific objectives are:1. To test 100 elite ILs and publicly release 1-2 transgressive Upland cotton cultivars with high lint yield, high levels of drought tolerance, and resistance to seedling diseases.2. To test 100 elite ILs and publicly release 1-2 Upland cotton cultivars with long, strong and fine fibers, and resistance to Verticillium wilt, Fusarium wilt race 4 (FOV4), spider mites, and thrips transferred from Pima cotton.
Project Methods
1. Year 2025- Field tests in four locations (SC, MS, TX, and NM) Materials: Based on results for yield, agronomic traits and fiber quality in the three locations and resistance/tolerance to thrips (in NM), spider mites (MS), seedling damping-off, Verticillium wilt (NM), and Fusarium wilt race 4 (NM), and drought (TX) from 2024 and previous years, 40 ILs will be selected. Methods: Delinted seeds for the selected 30 ILs, together with four checks, will be grown again in four locations- Las Cruces, NM, Lubbock, TX, Stoneville, MS, and Florence, SC (representing the Southeast Cotton Belt). The test will be arranged using a RCBD with four replications in each location. The plot size will be 2- rows × 10-15 m with a row-spacing of 0.92 m. Seed planting, crop management, boll sampling, ginning, mechanical harvesting, and evaluations of agronomic traits, yield, and fiber quality will follow the same procedure as described above. The results from the above three replicated tests will be jointly analyzed using a combined analysis of variance (ANOVA) to account for genotype × environment interactions.2. Years 2026-2027 Multi-location field tests across the Cotton Belt Materials: Based on results for yield, agronomic traits, fiber quality, and resistance/tolerance to thrips, spider mites, seedling damping-off, Verticillium wilt, Fusarium wilt race 4, and drought from 2024 and 2025, 9 ILs with overall best performances will be selected. Methods: Delinted seeds for the 8 selected ILs (two best ILs selected from each of the four testing locations, which are also top performers across the three locations) will be submitted to the Regional High-Quality Test (RHQ) in 2026-2027. The annual RHQ (part of the National Cotton Variety Tests- NCVT, Zeng 2021) has been coordinated by the Crop Genetics Research Unit, USDA-ARS, Stoneville, MS, for more than 20 years (Meredith et al. 2012; Zeng et al. 2015, 2019), and currently led by Dr. Linghe Zeng (Cooperator of this proposed project). RHQ testing locations historically include Virginia, North Carolina, South Carolina, and Alabama in the Southeast region, Missouri, Arkansas, Tennessee, Mississippi, and Louisiana in the Mid-south region, Oklahoma and Texas in the Southwest region, and New Mexico, Arizona, and California in the West region. However, due to changes in cooperators, several states have not participated in the testing program in recent years. For this proposed breeding project, locations from 5-7 states will be added to the three testing locations (Stoneville, MS; Lubbock, TX; and Las Cruces, NM for this proposed project) that are also part of the RHQ. The 9 ILs, together with other RHQ entries including two national standards from seed companies and other public breeding programs will be tested in all the RHQ locations. The test in each location will be arranged using a RCBD with four replications. The plot size will be 2- rows × 10-15 m with a row-spacing of 0.92 m. Seed planting and crop management will follow local recommendations for each location. At crop maturity, boll sampling, ginning, mechanical harvesting, and evaluations of agronomic traits, yield, and fiber quality will follow the same procedure as described above. As required, fiber samples in each location will be sent to the Cotton Structure and Quality Research Unit, USDA-ARS, New Orleans, Louisiana, for testing fiber quality including fiber length, uniformity, strength, elongation, and micronaire. Seedcotton in each plot will be mechanically harvested and weighed using a 2-row plot picker in each location. The seedcotton yield will be converted to lint yield by multiplying it with lint percentage from the boll samples. The results from the above replicated tests will be jointly analyzed using a combined analysis of variance (ANOVA) for mean separation.3. Evaluation of ILs for drought tolerance and resistance to thrips, spider mites, Verticillium wilt, Fusarium wilt race 4, and damping-off caused by Rhizoctonia solani. Drought: Lubbock, TX represents a dryland cotton production system. The testing site and the local crop management practices will be used to evaluate selected ILs for field drought tolerance in the tests of 2024-2027 as described earlier, based on visual ratings on plant height, boll loading and maturity and seedcotton and lint yields harvested. Thrips: Evaluations will be performed under natural infestation conditions in both the field and greenhouse in Las Cruces, NM, using a rating scale of 0 for immunity to 7 for plant death. Spider mites: Field evaluation of spider mite resistance will be conducted in Sept. each year in conjunction with the replicated field tests in Stoneville, MS, in 2024 to 2026. Greenhouse evaluation for the ILs using the same experimental designs will also be done under the natural infestation conditions based on the above rating scale. Verticillium wilt: Evaluation of Verticillium wilt resistance for the selected ILs in this study will be conducted in the greenhouse based on our established artificial inoculation method.Because Verticillium wilt is a vascular fungal disease, we will further rate the severity of vascular discoloration in individual plants under evaluation. Fusarium wilt race 4:We have developed a reliable evaluation method in the greenhouse, using a three-step evaluation procedure including: (1) growing seeds in Fusarium wilt race 4- infested soil; (2) artificial inoculation after seedling emergence; and (3) transplanting survived plants at 4-5 true leaf stage in large pots containing infested soil to grow to maturity. Data on seedling mortality and vascular discoloration will be collected. Because Fusarium wilt is a vascular fungal disease, we will use a rating scale to quantitatively evaluate vascular discoloration. Resistant ILs will be further evaluated in a Fusarium wilt race 4- infested field (Fabens, TX) using our established field experimental methods. Seedling damping-off: Using an artificial inoculation method in 2023, we screened 600 Upland cotton accessions for resistance to R. solani (Zhang et al. unpublished). We will use the same screening method to evaluate the entire set of ILs in the greenhouse in Las Cruces, NM, by sowing 15 seed/pot in pre-infested soil using one replication first. Data on seedling emergence and mortality for each IL will be collected and analyzed. For these ILs with moderate to high levels of seedling survivals, a replicated confirmation test using RCBD with 4 replications will be conducted. 4.Year 2028- Cultivar release Results from all the field and greenhouse tests in 2024 to 2027 will be statistically analyzed to determine ILs to be released as commercial cultivars and/or elite germplasm lines. Release notices will be written and submitted to Agricultural Experimental Stations in New Mexico and Texas and USDA-ARS for approval as public releases. Once approved, each cultivar/germplasm release notice will be submitted to Journal of Plant Registrations for publication. Acid-delinted seeds at required amounts will be sent to the National Laboratory for Genetic Resources Preservation (NLGRP), USDA-ARS, Fort Collins, Colorado, for long-term storage and subsequent distribution. Breeder's seeds will be provided to New Mexico and Texas Plains Cotton Growers Associations for seed increase and commercialization.