Detection and Varification of An Aphid Resistance Locus in Soybean PI 567543C.

The soybean aphid (Aphis glycines Matsumura) is an important pest on soybean [Glycine max (L.) Merr.] in North America. Aphid resistance has recently been found on plant introduction (PI) 567543C, but little is known about its genetic control. The objectives of this study were to identify the resistance genes in PI 567543C with molecular markers and validate them in a different genetic background. A mapping population of 249 F₃ derived lines from a cross between PI 567543C and a susceptible parent was investigated for the aphid resistance in both greenhouse and field. The broad sense heritability of aphid resistance in the field trial is over 0.95. The segregation of aphid resistance in this population suggests a major gene controlling the resistance. Bulked segregant analysis with molecular markers revealed a potential genomic region. After saturating this putative region with more markers, a genetic locus was mapped in an interval between Sat_339 and Satt414 on chromosome 16 (linkage group J) using the composite interval mapping method. This locus explained the majority of the phenotypic variation ranging from 84.4% in the field trial to 90.4% in the greenhouse trial. Moreover, this resistance locus was confirmed using a validation population. This aphid-resistant gene could be valuable in breeding aphid-resistant cultivars.