David Walker, USDA-ARS Invasive Weed Management Research Unit, 232 National Soybean Research Center, 1101 W Peabody Dr, Urbana, IL 61801
Identification and utilization of genetically diverse sources of resistance will be important in the effective management of Asian soybean rust. Interactions between host and pathogen genotypes, environmental conditions, plant maturity, differences among mechanisms of resistance, and other factors make identification of resistant germplasm a challenge. Most sources of resistance are agronomically poor, so a second challenge involves the transfer of resistance genes from these accessions to the genetic backgrounds of high-yielding cultivars and breeding lines adapted to North America. Furthermore, geographical and seasonal restrictions on assessment of rust resistance present a major obstacle to both objectives. This presentation summarizes what has been learned about recognizing useful resistance, and ongoing efforts to introgress resistance genes from primarily low-yielding Asian sources into elite germplasm through the integration of conventional and molecular breeding techniques.