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

Authors: DIERS, BRIAN - University Of Illinois; Lagos-Kutz, Doris; SCHULTZ, SARAH - University Of Illinois; CARY, TROY - University Of Illinois; WANG, DECHUN - Michigan State University; Hartman, Glen

Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2022
Publication Date: 2/23/2023
Citation: Diers, B., Lagos-Kutz, D.M., Schultz, S.J., Cary, T., Wang, D., Hartman, G.L. 2023. Registration of 64 soybean germplasm lines with all combinations of five soybean aphid resistance genes in two genetic backgrounds. Journal of Plant Registrations. 17(2):416-425. https://doi.org/10.1002/plr2.20279.
DOI: https://doi.org/10.1002/plr2.20279

Interpretive Summary: Soybean aphid is a serious pest in North America and infestations can cause economically significant losses to the soybean crop. Aphid resistance genes have been identified and deployed with some success; however, biotype of the soybean aphid are known that overcome single aphid resistance genes. In this study, we stacked five aphid resistance genes in different combination into the background of two soybean cultivars resulting in 32 combinations of these five genes in each cultivar. These lines were evaluated for agronomic traits in the field and for resistance to four soybean aphid biotypes. Most of the backcross lines had yield performance that did not differ from the recurrent parent. Those lines with the Rag6 (resistance to Aphis glycines) 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, the interaction between resistance genes and aphid isolates, and for breeders who are developing germplasm with resistance gene pyramids. This information will be useful to soybean scientists and producers that could benefit from growing aphid resistant cultivars.

Technical Abstract: Soybean aphid is a serious pest in North America and infestations can cause economically significant losses to the soybean crop. 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 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 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, most of the backcross lines had yield performance that 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, the interaction between resistance genes and aphid isolates, and for breeders who are developing germplasm with resistance gene pyramids.