Fiber and Industrial Applications
Cotton ‘U1’ – FOV4 Resistance
A PUBLIC-PRIVATE SECTOR COLLABORATION USING THE USDA-ARS NATIONAL PLANT GERMPLASM SYSTEM’S NATIONAL COTTON GERMPLASM COLLECTION TO ADDRESS THE FOV4 PATHOGEN OF UPLAND COTTON
Don C. Jones
Cotton Incorporated, 6399 Weston Parkway, Cary, North Carolina 27513.
Corresponding author: djones@cottoninc.com
OUTLINE
- Summary
- Problems addressed
- Solutions developed
- Impact
- Germplasm
- Additional resources
- References
- Chapter information
1. SUMMARY
Screening 8,000 accessions from dozens of breeders and the National Plant Germplasm System (NPGS) National Cotton Germplasm Collection, collaborating scientists from four institutions developed six highly FOV4-resistant Upland cotton lines through a complementary protocol of disease screening in the field and molecular techniques. Causative genes for host-plant resistance and genetic markers tightly linked to those genes were discovered and made available to eager private-sector seed partners to incorporate into their commercial varietal development pipelines.
The overall objectives were to discover and publicly release highly FOV4-resistant Upland germplasm and identify the causative genes and linked markers for that resistance.
Download a printable fact sheet by clicking the image below.
2. PROBLEMS ADDRESSED
In 2017 Dr. Jim Olvey, a private-sector Pima cotton breeder, alerted Dr. Don Jones of Cotton Incorporated about the presence of Fusarium wilt race 4 (FOV4) in Upland cotton near El Paso, Texas. This devasting fungal pathogen causes Fusarium wilt disease and had previously only been observed in California in the United States. There it caused such devastation that Upland cotton acreage was reduced by more than 95% between 2000 and 2020 due to susceptibility to the pathogen. In spite of more than 15 years of research, robust and validated resistance to this pathogen had been elusive to identify in Upland cotton. This prompted a renewed effort by the research community to find resistance.
3. SOLUTIONS DEVELOPED
Cotton Incorporated spearheaded a private/public sector collaboration to leverage complementary skills of the scientists invited to form the research team. The team conducted screenings in a field in Texas with a high pathogen load utilizing proprietary cotton check lines developed by Dr. Olvey. The field screening was led by Dr. Olvey and his son Mike.
As background, Dr. Olvey began screening breeder submissions and NCGC cotton accessions, including SA3208 (NPGS PI 694583), in 2006. He made single plant selections from that line, which were then rescreened and single plant selections were made again in 2007, 2008, and 2012 in a high FOV4 pathogen load nursery site in California. In 2018, when the collaboration to solve the FOV4 problem in Upland cotton was established, Dr. Olvey resurrected the SA3208 segregates.
Six Upland lines highly resistant to FOV4 were identified: U1, U2, U3, U4, U5, and U7. Results were validated by 30+ replications over a minimum of three years (2018, 2019, 2020) before resistance claims were first publicly announced in 2021. U1, the first released line, was provided to public and private-sector cotton breeders and seed providers, who then promptly incorporated it into their breeding pipelines.
In addition to breeding these resistant lines, the team develop an in vitro system that showed that FOV4 was indeed the causative pathogen and that a plant’s response is different to FOV4 versus FOV7 (Parris et al., 2022). The geostatistical Kringing procedure was applied to make field screening more effective (Parris et al., 2023). Two causative genes for host-plant resistance to FOV4 in Upland cotton, located on chromosomes D03 and A02, were identified and their mode of action was described by Parris et al. (2025).
Collaborators involved in developing solution:
- Dr. Don C. Jones, Cotton Incorporated, Cary, North Carolina, USA
- Dr. Chris Saski and Dr. Stephen Parris, Clemson University, Clemson, South Carolina, USA
- Dr. Jim Olvey and Mr. Mike Olvey, O&A Enterprises, Maricopa, Arizona, USA
- Dr. Avinash Sreedasyam, HudsonAlpha Institute for Biotechnology, Huntsville, Alabama, USA
4. IMPACT
The highest acreage of Upland cotton in the world is grown in West Texas. Thus, discovery of the devasting FOV4 pathogen in El Paso, TX sent shock waves through the cotton industry. Applying proven protocols developed in a highly successful Pima cotton breeding program, coupled with newly discovered genomic techniques, the research team quickly identified highly FOV4 resistant Upland germplasm, created a new in vitro screening protocol for host-plant resistance to FOV4, and uncovered the two causative host-plant resistance genes and genetic markers tightly linked to those genes. The host-plant resistance to FOV4 could generate potential savings of hundreds of millions of dollars for U.S. cotton producers.
5. GERMPLASM
Genebank accession SA3208 (PI 694583) was used to develop FOV4 resistant lines of Upland cotton, including U1.
6. ADDITIONAL RESOURCES
Download to view slides from Dr. Chris Saski’s presentation at 2024 Cotton Breeders’ Meeting in Cary, North Carolina.
Clemson News reports “Clemson, Australian scientists unite to combat Fusarium wilt in cotton“.
Cotton Farming, a popular grower publication, reports “The Fight Against FOV4 Continues In Texas“.
Numerous presentations on FOV4 resistance have been delivered at the National Cotton Council’s Beltwide Cotton Conferences between 2021 and 2025.
7. REFERENCES
Parris S, Huang W, Jones D, Bridges W, Olvey J, Olvey M, Saski C. 2023. Geostatistical techniques to account for the heterogeneity of Fusarium wilt inoculum distribution in upland cotton field screening studies. Crop Science 63:1316-1329. https://doi.org/10.1002/csc2.20961
Parris SM, Jeffers SN, Olvey JM, Olvey II JM, Adelberg JW, Wen L, Udall JA, Coleman JJ, Jones DC, Saski CA. 2022. An in vitro co-culture system for rapid differential response to Fusarium oxysporum f. sp. vasinfectum race 4 in three cotton cultivars. Plant Disease 106:990-995. https://doi.org/10.1094/PDIS-08-21-1743-RE
Parris S, Lovell JT, Ding F, Zhang Z, Olvey J, Olvey M, Schmutz J, Grimwood J, Sreedasyam A, Kumar S, Li Z, Joshi P, Jenkins JW, Plott C, Stewart A, Webber J, Stiller WN, Jones DC, Saski CA. 2025. Polyploidy-mediated variations in glutamate receptor proteins linked to Fusarium wilt resistance in upland cotton. The Plant Journal 122:e70125. https://doi.org/10.1111/tpj.70125
8. CHAPTER INFORMATION
Citation: Jones DC. 2026. Cotton ‘U1’ – FOV4 Resistance. In: Volk GM, Chen KY, Byrne PF, Bretting PK (Eds.) Plant Genetic Resources: Success Stories. Fort Collins, Colorado: Colorado State University. Date accessed. Available from https://colostate.pressbooks.pub/pgrsuccessstories/chapter/cotton-u1-fov4-resistance/
Content originally submitted: February 24, 2026
Date of publication: May 4, 2026
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