Analysis and Identification of QTL for Resistance to Sclerotinia Sclerotiorum in Pea (Pisum sativum L.)

Abstract

White mold caused by Sclerotinia sclerotiorumi s one of the most devastating diseases infecting field pea (Pisum sativum L.) which causes severe yield loss worldwide. Population 17 (Lifter/ PI240515), and Population 19 (PI169603/ Medora) were developed by single seed descent and screened by greenhouse evaluation and detached stem assay to identify potential sources of white mold resistance. Twenty-two partial resistant inbred lines were identified with short internode which met at least two resistance criteria based on lesion expansion inhibition (LEI) and nodal transmission inhibition (NTI). To find SNPs (single nucleotide polymorphism) responsible for white mold resistance, Populations 17 and 19 were genotyped using GBS (genotyping by sequencing) methodology and analyzed with the GBS-SNP-CROP pipeline. Linkage maps were constructed for each population and a composite map based on shared SNPs between the two populations was also generated. Nineteen QTL were identified as contributing to resistance to white mold. Seventeen were associated with LEI and two were associated with NTI. The QTL responsible for lesion expansion on LG VII were duplicated in the short internode subset of both populations. Partially resistant inbred lines and QTL responsible for white mold resistance identified in this study can be useful as resources for resistance to S. sclerotiorum in further experiments aimed at developing resistant cultivars.