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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #348696

Research Project: Genetic Enhancement of Lettuce, Spinach, Melon, and Related Species

Location: Crop Improvement and Protection Research

Title: Characterization of resistance to lettuce drop, and its association with plant architecture and composition in lettuce

item MAMO, BULLO - University Of California
item Adhikari, Neil
item FOSTER, CLIFF - Michigan State University
item ZUCKER, LEAH - California Polytechnic State University
item Hayes, Ryan
item SUBBARAO, KRISHNA - University Of California
item Simko, Ivan

Submitted to: International Congress of Plant Pathology Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 12/8/2017
Publication Date: 8/3/2018
Citation: Mamo, B.E., Adhikari, N.D., Foster, C., Zucker, L., Hayes, R.J., Subbarao, K.V., Simko, I. 2018. Characterization of resistance to lettuce drop, and its association with plant architecture and composition in lettuce. International Congress of Plant Pathology, July 29-August 3, 2018, Boston, Massachusetts.

Interpretive Summary:

Technical Abstract: Cultivated lettuce (Lactuca sativa L.) is an economically important vegetable crop. Lettuce drop, caused by the fungal pathogens Sclerotinia minor and Sclerotinia sclerotiorum, causes significant yield loss in all lettuce types. Identification and deployment of genetic resistance has been impeded by the lack of resistance in lettuce germplasm. Resistance to the disease in lettuce landraces and non-adapted accessions cultivated for seed (oil consumption) is often linked with plant architecture associated with premature bolting. Resistance to crown degradation due to Sclerotinia infection in non-leafy lettuce accessions increases with plant age. Our research is focused on understanding the relationship between plant architecture and crown degradation due to Sclerotinia infection, and identify possible mechanisms underlying resistance. Preliminary results indicate that resistance to crown degradation is associated with stem strength and cell wall composition. Comprehensive cell wall composition analysis from susceptible vs. resistant accessions will be discussed. For genetic analysis, a recombinant inbred lines (RILs) population derived from a cross between a susceptible cultivar and a resistant accession, and genotyped with molecular markers has been identified. This population is being evaluated for lettuce drop incidence, disease severity and rate of bolting in a field infested with S. minor. The RILs will also be evaluated for stem firmness, and possibly cell wall composition. QTL analysis on these traits will narrow down the location of the gene(s) responsible for Sclerotinia resistance, its association with development-related traits and cell wall composition in lettuce.