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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Research Project #437875

Research Project: Identifying the Basis of Lettuce Drop Resistance to Develop Cultivars With Superior Resistance

Location: Crop Improvement and Protection Research

Project Number: 2038-21530-002-029-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Nov 1, 2019
End Date: Feb 28, 2022

Objective:
1) Develop new tools to detect, eradicate, and control pests and diseases. 2) Prevent and manage pests and diseases to minimize economic and environmental harm to specialty crop growers. 3) Enhance speed and reliability of detection methods. 4) Utilize innovative solutions to address threats, including engineering or cultural solutions.

Approach:
Lettuce drop is an economically important soil borne disease of lettuce. It is caused by two fungal pathogens, Sclerotinia minor and S. sclerotiorum, resulting in the total collapse of the entire plant before harvest. Fungicides and cultural methods have traditionally been used for lettuce drop control with unsatisfactory results. The incorporation of genetic resistance in lettuce drop management would provide a sustainable approach to the loss of produce. Research funded previously by the California Specialty Crop Block Grant Program (SCBGP) identified resistance not affected by the current breeding program. The mechanism of this resistance is largely unknown. To complement preliminary data from the previous project, this project proposes to evaluate disease symptoms, quantitative phenotyping, and tissue composition to incorporate the findings in breeding. The success of the project will be measured by the number of new diagnostic techniques developed for detecting lettuce drop resistance. This project addresses the program priorities of developing new tools to detect, eradicate, and control pests and diseases; preventing and managing pests and diseases to minimize economic and environmental harm to specialty crop growers; enhancing speed and reliability of detection methods; and utilizing innovative solutions to address threats, including engineering or cultural solutions. This project develops new diagnostic tools to detect lettuce drop resistance. The incorporation of genetic resistance in the control of lettuce drop reduces production of inoculum in the soil by Sclerotinia spp. Resistance-based prevention and management of lettuce drop reduces dependence on fungicides and cultural methods, both of which are costly and harmful to the environment and human health. This project would advance the understanding of the mechanisms of lettuce drop resistance that can be utilized in breeding through traditional or alternative means.