Quantitative Trait Loci (QTL) that Underlie SCN Resistance in Soybean [Glycine max (L.) Merr.] PI438489B by ‘Hamilton’ Recombinant Inbred Line (RIL) Population

Abstract

Soybean cyst nematode caused by Heterodera glycines Ichinohe is the most devastating pest in soybean [Glycine max (L.) Merr.]. Resistance to SCN is complex, polygenic, race and cultivar specific, and it is controlled by several quantitative trait loci (QTL). Our objective was to identify and map QTL for SCN resistance to races 3 (HG Type 0) and 5 (HG Type 2.5.7) using a high density SNP-based genetic linkage map based on the PI438489B by ‘Hamilton’ (PIxH, n=50) recombinant inbred line population. The PI438489B by Hamilton map contained 648 SNPs distributed on 31 LGs with coverage of 1,524.7 cM and an average distance of 2.35 cM between two markers (Kassem et al., 2011). Using interval mapping (IM) and composite interval mapping (CIM), eight QTL were identified for SCN resistance to races 3 and 5 on 7 different soybean chromosomes. Four QTL for resistance to SCN race 3 were identified and mapped on chromosomes 7, 13, 15, and 16. Similarly, four QTL for resistance to SCN race 5 were identified and mapped on chromosomes 5, 8, and 11. The QTL identified here will be highly beneficial in breeding programs to develop cultivars with resistance to both SCN races 3 and 5.