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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Research Project #433019

Research Project: New Lettuce Cultivars with Resistance to Lettuce Drop

Location: Crop Improvement and Protection Research

Project Number: 2038-21530-002-04-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 1, 2017
End Date: Dec 31, 2020

The objective of the research is development of lettuce cultivars (breeding lines) with resistance to lettuce drop caused by Sclerotinia minor. In addition, we will map genes for resistance to lettuce drop and identify determinants for partial resistance to the pathogen.

University of California (UC) Davis and the USDA, Agriclutrual Research Service (ARS) in Salinas, California have identified high level resistance in the cultivar Eruption, which could reduce losses by about 50 percent if its resistance genes are bred into new cultivars. We will mate cv. Eruption (small Latin type of lettuce) with romaine cultivars to introgress genes for partial resistance to romaine type lettuces. This project will develop lettuce with resistance from Eruption and determine their adaptation to winter and summer production in California. The other part of the project will focus on determining the genetics of resistance in a population of recombinant inbred lines (RILs) derived from a cross with Eruption. To achieve this goal, a population of 160 RILs from the cross Batavia Reine des Glaces (lettuce drop susceptible) x Eruption will be genotyped with molecular markers and phenotyped in multiple field and greenhouse experiments. In addition, we will analyze plant architecture, earliness, composition of plant to identify resistance loci that are independent of plant morphology.