Location: Crop Improvement and Protection Research
Project Number: 2038-22000-019-059-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Feb 1, 2024
End Date: Jan 31, 2025
Objective:
1. Identify of heirloom and wild strawberry cultivars with resistance to Fusarium oxysporum f. sp. fragariae race 2 isolates that were recently discovered in California.
2. Determine the environmental conditions necessary for sporodochia formation and spore release.
3. Determine the foliar-infective potential of spores produced by sporodochia on strawberry foliage.
4. Establish spore traps and test for Fusarium oxysporum f. sp. fragariae race 2 in Oxnard, California.
Approach:
1. Test 386 wild and heirloom strawberry varieties for resistance to Fusarium oxysporum f. sp. fragariae race 2 in growth chamber experiments at the USDA-ARS in Salinas. Plants will be inoculated with a spore suspension and maintained for 8 weeks, with weekly symptom montoring.
2. Inoculate susceptible strawberry plants with Fusarium oxysporum f. sp. fragariae race 1 and place them in growth chambers with low (0-20%), medium (40-60%), and high (80-100%) relative humidity. There, they will be grown and the abundance of sporodochia quantified with ImageJ after a period of 8 weeks.
3. Conidia will be obtained from sporodochia, diluted into a suspension, then placed on known inoculation points on strawberry leaves. Inoculated plants will be growth over a period of 12 weeks and destructively sampled to determine if infection occurred and spread from inoculation points. Plants will also be monitored for wilt symptoms.
4. Cyclone-based spore traps will be establishd in Oxnard, California. DNA will be extracted from spore trap samples and tested by qPCR to determine the abundance of Fusarium oxysporum f. sp. fragariae race 2.
