Location: Crop Improvement and Protection Research
Project Number: 2038-21530-003-032-T
Project Type: Trust Fund Cooperative Agreement
Start Date: Apr 1, 2026
End Date: Mar 31, 2027
Objective:
Lettuce production in California faces significant losses from diseases including impatiens necrotic spot virus (INSV), Pythium wilt, Verticillium wilt, and Fusarium wilt. Three of these have a broad host range including cultivated and weed species found throughout the area, which makes control by rotation nearly impossible. Fumigation for soil-borne diseases is increasingly unavailable due to chemical restrictions and high associated costs. Therefore, genetic resistance is the ideal, and often only, solution to control spread and reduce losses. The overall goal of this continuing project is to release lettuce with improved resistance to diseases impacting production. Associated with this are annual objectives to develop germplasm, information, and tools that move us closer to this goal. For 2026-2027 our objectives are to: 1) develop lettuce germplasm resistant to INSV, 2) develop tools to evaluate germplasm resistance to Pythium wilt, 3) characterize resistance to co-infection by Verticillium and Fusarium wilts and develop improved lettuce germplasm, and 4) characterize the variant isolate and develop germplasm with resistance to Fusarium wilt.
Approach:
• Objective 1- Develop and release germplasm with resistance to impatiens necrotic spot virus (INSV).
• Objective 2- Correlate greenhouse and field germplasm evaluations for resistance to Pythium wilt.
• Objective 3- Develop and release germplasm with resistance to co-infection of Verticillium wilt and Fusarium wilt.
• Objective 4- Characterize the variant isolates and develop germplasm with broad-spectrum resistance to Fusarium wilt.