Glycine latifolia Random survey

Sclerotinia sclerotiorum causes Sclerotinia stem rot, which results in significant yield losses in soybean (Glycine max) in epidemic years. Varying levels of partial resistance to Sclerotinia stem rot have been identified in cultivated soybean. However, this resistance is conditioned by multiple quantitative loci each with small effects, some of which alter plant development and/or architecture. Cultivated soybean has a relatively narrow genetic base and no fully resistant soybean varieties have been found to date. In contrast, wild soybean species show much wider ranges of responses to infection by S. sclerotiorum. While most accessions, like most cultivated soybean lines, are killed by the fungus, a small number of accessions show high levels of resistance and survive multiple inoculations with the fungus. The objectives of this study are to: 1) generate mapping populations in two perennial Glycine species that segregate high levels of resistance to Sclerotinia stem rot and characterize the responses of derived recombinant inbred lines (RILs) to S. sclerotiorum infection; 2) Identify single nucleotide polymorphisms (SNPs) and construct high-density genetic maps for the RIL population(s) produced in Objective 1; and 3) identify loci that contribute to Sclerotinia stem rot resistance in two perennial Glycine accessions and evaluate their novelty relative to loci previously identified in G. max. The project will address the goals and priorities of the Sclerotinia Initiative by genetically characterizing resistant plant germplasm resources and developing genomic resources to identify chromosomal regions conditioning high levels of resistance to Sclerotinia stem rot in perennial Glycine species.