Multi-Parent Advanced Generation Inter-Cross Population for Improvement of Genetic Resistance of Dry Bean to White Mold

Abstract

White mold (Sclerotinia sclerotiorum Lib. de Bary) is one of the most important diseases of common bean in the U.S. with seed yield losses up to 100%. White mold resistance is hard to incorporate into breeding materials because of low heritability, cumbersome screening methods, and few sources of resistance. A Multi-parent Advanced Generation Inter-Crosses population was created to develop resistant germplasm and map the genetics factors controlling the resistance. A seedling straw test method was used to identify resistant lines. Twenty genotypes were found to be resistant based on its response when inoculated with isolate 1980 of white mold. GWAS using quantitative, polynomial and binomial phenotypic distribution data, identified 30 genomic regions associated with resistance on Pv01, Pv02, Pv04, Pv05, Pv07, Pv08, Pv10 and Pv11. Cumulative R2 values were 57% for binomial distribution using 13 genomic intervals, 41% for polynomial using 8 intervals, and 40% for quantitative using 11 intervals.