Quantitative trait loci underlying resistance to three soybean cyst nematode populations in soybean PI 404198A

Soybean cyst nematode (SCN) (Heterodera glycines Ichinobe) is a major pest of soybean [Glycine max (L.) Merr.] in the USA. Soybean plant introduction (PI) 404198A is one of the newly identified sources that can provide a broad spectrum of resistance to SCN. The objective of this study was to identify quantitative trait loci (QTL) associated with resistance to SCN races 1, 2, and 5 in PI 404198A. Linkage groups (LGs) G and A2 were found to be associated with resistance to race 1. QTL on LG G was located on the Satt309-Satt688 region, and it explained a larger proportion of the total variation (20.2%). QTL on LG A2 was located at the Satt424-Saff632-Sat_406 region, and it accounted for a smaller proportion (9%). LGs G and III were shown to be associated with resistance to race 2. QTL on LG G was located on the Satt688-Satt309-Satt163 region, and it explained 12.5% of the total variation. Molecular marker Satt453 on LG B1 was found to be associated with resistance to race 2, and it explained 11% of the total variation. LGs G, 111, and N were found to be associated with resistance to race 5. QTL on LG G was located on the Satt688Satt309-Satt163 region, and it explained 6.3% of the total variation. Molecular marker Satt453 on LG 131 was found to be associated with resistance to race 5, and it explained a larger proportion of the total variation (13%). QTL on LG N was mapped on the Satt584-Sat_280Satt549, and it explained 9.5% of the total variation. In conclusion, soybean PI 404198A may carry rhg1 on LG G, Rhg4 on LG A2, and a QTL on LG B1. Further studies are needed to lend credibility for QTL on LG N.