Quantitative Trait Loci Analysis of Resistance to White Mold (Sclerotinia sclerotiorum) in Pinto Bean (Phaseolus vulgaris).

White mold, caused by Sclerotinia sclerotiorum (Lib.) De Bary, is a serious yield reducing fungal pathogen of common bean (Phaseolus vulgaris L.).  Pinto beans are the most widely grown commercial class of dry beans in the U.S. and are among the most susceptible to white mold. The objective of this study was to identify QTL for resistance to white mold and associated agronomic traits in two recombinant inbred line (RIL) pinto bean populations derived from a common parent AN-37. The two pinto bean RIL populations were genotyped with SSR, InDel and SNP markers resulting in two linkage maps of 1183 and 953 cM. A total of fifty QTL were identified in different years for eight traits (white mold disease incidence, seed yield, days to flowering, days to maturity, 100 seed weight, canopy height, lodging and the straw test). These QTL were located across all 11 chromosomes with LOD scores ranged from the threshold of 2.5 to 10.5. Six new QTL for yield were identified on Pv01, Pv02, Pv03, Pv05 and Pv09.  Seven new QTL for white mold were identified on Pv01, Pv04, Pv07 and Pv08 and two previously identified QTL were validated on Pv02 and Pv03.