Discovery And Refinement Of QTLs Associated With SCN Resistance In PI 437654.

The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, has been recognized
as a major problem impacting soybean production across the USA. Planting SCN resistant soybean cultivars is the most cost effective control method. PI 437654 is a unique accession because of its resistance against nearly all popular SCN races. With restriction fragment length polymorphism (RFLP) markers, few QTLs associated with SCN resistance had been previously identified in a cross between ‘BSR101’ and PI 437654. The QTL regions located on four known linkage groups (LG-A2, -C1, -G and -M) and two unknown linkage groups (LG-25 and LG-26) have been patented by Pioneer Hi-Bred International, Inc. In this study, using 276 molecular markers (SSR and AFLP) we refined the locations of major reported QTLs identified from PI 437654 (or other resistant PIs), and we also detected few new QTLs for SCN resistance using a population of 205 recombinant inbred lines (RILs) from a cross of Essex x PI 437654. Three to eight QTLs with additive effects and two to six epistatic interactions were identified to be associated with SCN resistance to race 1, 2, 3, 5 or 14. Except reported QTL on LG A2, B1 and G, a novel QTL associated with SCN resistance to race 2, 3, 5, and 14 was identified on LG-I. By screening another RIL population with different genetic background, confirmation of new QTL is underway.