New soybean aphid resistance genes. This project will identify, characterize, and map the location of at least one newly identified soybean gene that gives resistance to soybean aphids. This gene and information on linked markers will be made available to soybean breeders, which will facilitate the development of new soybean cultivars with broad-spectrum aphid resistance using marker-assisted selection breeding procedures.

Markers associated with soybean aphid virulence. At least one aphid marker associated with virulence on a Rag gene will be identified. Use of this virulence-associated aphid marker will help determine potential for aphids in samples collected in specific areas to attack plants with the Rag gene. Information on virulence potential will help maximize the effectiveness of soybean aphid management with resistance by guiding stakeholders, such as seed companies, extension entomologists, and crop consultants on where cultivars with Rag genes should be deployed for maximum effectiveness, and soybean grain producers on selecting soybean cultivars with appropriate Rag genes for their farms. Use of the virulence-specific markers will enable a novel strategy to manage soybean resistance genes that will maximize resistance and lengthen the time of effective service of Rag genes.

Information on biochemical differences between soybean aphid biotypes. This information will lead to and
understanding of the mechanism of virulence and a possible protein-based marker between aphids and
soybean plants.

Results presented in scientific and grower publications. Results on the identification of new soybean aphid
resistance, prevalence of virulent aphid genotypes in the western part of the soybean-growing region, and on how virulent aphid genotypes increase on resistant cultivars in the field, will be disseminated to the scientific and grower communities.