Quantitative Trait Loci Underlying Resistance to Sudden Death Syndrome (SDS) in MD96-5722 By ‘Spencer' Recombinant Inbred Line Population of Soybean.

The best way to protect yield loss of soybean [Glycine max (L.) Merr.] due to sudden death syndrome (SDS), caused by Fusarium virguliforme (Aoki, O’Donnel, Homma & Lattanzi) is the development and use of resistant lines. Mapping quantitative trait loci (QTL) linked to SDS helps developing resistant soybean germplasm through molecular marker-assisted selection strategy. QTL for SDS were identified from a high-density SNP-based genetic linkage map of MD 96-5722 by ‘Spencer’ recombinant inbred line (RIL) population, using SoySNP6K Illumina Infinium BeadChip genotyping array.  Ninety-four F_5:7 RIL were evaluated for two years (2010 and 2011) at two environments (Carbondale and Valmeyer) in southern Illinois to identify QTL linked to SDS resistance. Our analysis identified 19 QTL, which were mapped on 11 separate linkage groups (LG) or chromosomes (Chr). Many of these significant QTL identified in one environment/year were confirmed in another year or environment, which suggests a common dependence on genetic background for expression and had dominant monogenic resistance inheritance of the pathogen. These new QTL are useful sources for SDS resistance studies in soybean breeding, complementing previously reported loci.