Registration of 64 soybean germplasm lines with all combinations of five soybean aphid resistance genes in two genetic backgrounds

Abstract

Soybean aphid is a serious pest in North America, and infestations can cause economically significant losses. Aphid resistance genes have been identified and mapped with genetic markers, and the deployment of cultivars with pyramids of these genes could offer durable resistance. There is a need, however, for soybean [Glycine max (L.) Merr.] lines with different gene pyramids to be developed and tested to improve our understanding of what combinations provide the most resistance across aphid biotypes. We backcrossed the resistance genes Rag1, Rag2, Rag3, Rag4, and Rag6 into the background of two soybean cultivars, and lines with all 32 combinations of these five genes were developed in each background. These lines, LD19‐APH01–LD19‐APH64 (Reg. no. GP‐459–GP‐522, PI 701410–PI 701473), were evaluated for agronomic traits in the field and lines from one background were evaluated for resistance to four soybean aphid biotypes. There were significant differences among the performance of the backcross lines for agronomic traits; however, yield performance for most of the backcross lines did not significantly differ from the recurrent parent. Those lines with the Rag6 resistance gene and many gene pyramids showed a high level of resistance to all four aphid biotypes. Because these lines have the resistance genes in a mostly uniform background, they will be a useful source of germplasm for researchers studying soybean aphid isolates and the interaction between resistance genes and aphid isolates, as well as for breeders who are developing germplasm with resistance gene pyramids.