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 the 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
0%
Research Effort Categories
Basic
(N/A)
Applied
80%
Developmental
20%
Goals / Objectives
Cotton (Gossypium spp.) is the world's leading fiber crop and one of the most important oilseed crops. The U.S. ranks the third after India and China in cotton production; however, it is the leading exporter, accounting for approximately 35% of the global raw cotton trade (https://www.ers.usda.gov/topics/crops/cotton-and-wool/cotton-sector-at-a-glance/). Since 1995, the adoption of genetically engineered (GE) cotton with foreign genes for insect (Lepidoptera) resistance and herbicide tolerance (HT) has experienced exponential growth with production in 93-98% of the U.S. cotton acreage since 2014 (https://www.ers.usda.gov/data-products/adoption-of-genetically-engineered-crops-in-the-u-s). Commercial GE cotton cultivars have been exclusively developed by the private sector, and their production has several benefits including reduction in insecticides and carbon footprints and easement in managing weeds. However, U.S. cotton production has experienced three periods of yield stagnant and even decline since the mid-1990s. The current GE biotech traits have had their limitations. The need from U.S. farmers for cotton cultivars with high-yield, better fiber quality and resistance/tolerance to biotic and abiotic stresses has called solutions from public breeders using natural genetic variation.This proposal is based on our long-term extra-large population- based extensive efforts in introgression breeding between Upland cotton (G. hirsutum) and G. barbadense (known as Pima in the U.S. and hereafter Pima cotton) in the U.S. since the mid-1990s. 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; and (2) To test 100 elite ILs and publicly release 1-2 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
Year 2024- Field tests in three locations (MS, TX, and NM) Materials: Based on results for yield, agronomic traits, fiber quality, and resistance/tolerance to thrips, spider mites, seedling damping-off, Verticillium wilt and Fusarium wilt race 4, and drought from 2023 and previous years, a total of 200 ILs will be selected from more than 3000 ILs. Methods: Delinted seeds for the selected 200 ILs, together with four checks, will be grown again in the three locations- Las Cruces, NM (by PI Jinfa Zhang), Lubbock, TX (by Co-PI Jane Dever), and Stoneville, MS (by Cooperator Linghe Zeng). The test will be arranged using a randomized complete block design (RCBD) with three replications in each location. An augmented design will be used in that the four common checks will be grown in each block to estimate blocking effects and random errors. The plot size will be 1- row × 10-15 m with a row-spacing of 0.92 m. Field observations on morphological traits and uniformity will be made. Seed planting and crop management follow local cotton production recommendations in each location. At crop maturity, a sample of 50 open bolls from the middle of representative plants will be hand-harvested from each plot for ginning using a 10 or 20-saw lab gin. Seedcotton before ginning, and seed and lint after ginning will be weighed to determine boll weight, seed index (100 fuzzy seed weight in grams), and lint percentage. Lint samples will be sent to the Fiber and Biopolymer Research Institute, Texas Tech University, 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 installed with an automatic weighing system. The seedcotton yield will be converted to lint yield by multiplying it with the lint percentage from the boll samples. 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. Effects due to blocking and random environmental factors will be estimated based on the augmented design with the four common checks. If blocking effects are detected, observations in testing plots in each block will be adjusted accordingly before ANOVA for the 200 ILs.Year 2025- Field tests in three locations (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, 30 ILs will be selected. Methods: Delinted seeds for the selected 30 ILs, together with four checks, will be grown again in the three locations- Las Cruces, NM, Lubbock, TX, and Stoneville, MS. 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 ANOVA to account for genotype × environment interactions.Year 2026- 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 9 selected ILs (three best ILs selected from the MS, TX and NM testing locations, respectively, which are also top performers across the three locations) will be submitted to the Regional High-Quality Test (RHQ) in 2026. 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. Seedcotton in each plot will be mechanically harvested and weighed using a 2-row plot picker in each location. The results from the above replicated tests will be jointly analyzed using a combined ANOVA for mean separation.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 2024-2026 as described earlier, based on visual ratings on plant height, boll loading and maturity and seedcotton and lint yields harvested. Thrips and spider mites: Evaluations will be performed under natural infestation conditions in both the field and greenhouse in Stoneville, MS and Las Cruces, NM, based on established methods. Verticillium, Fusarium wilts and seedling damping-off: Evaluation of ILs for resistance to the diseases will be conducted in the greenhouse based on our established artificial inoculation method.Year 2027- Cultivar release Results from all the field and greenhouse tests in 2024 to 2026 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 the 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.