2013 Annual Report
1a.Objectives (from AD-416):
Phase III - Incorporate novel Soybean Cyst Nematode (SCN)-resistance genes into soybean germplasm of early maturity groups (I, II, III) combined with resistance to other economically important fungal disease with adequate agronomic performance.
1b.Approach (from AD-416):
This in an ongoing collaborative research project. In brief, Soybean populations and lines are continued to be developed using different sources of Soybean Cyst Nematode (SCN) resistance identfied by ARS scientist. Crossing are performed between new sources of resistance from ARS and the elite lines developed by Iowa State University (ISU). Crosses are peformed in Puerto Rico at ISU Research Station-Isabella in Puerto Rico. Selections for resistance using molecular markers tagged to SCN resistance are performed at USDA-ARS in Jackson, TN. Confirmation for SCN resistance is also accomplished at USDA-ARS greenhouses located in Jackson, TN, for selected advanced lines and populations. ARS scientist has developed and standardized greenhouse bioassays for SCN resistance and also maintains cultured nematode populations for stable reactions. Concurrent field evaluations are done in three locations, ISU-Puerto Rico, ISU-Ames, IA, and USDA-ARS, Jackson, TN, using standard methods.
In this ongoing collaborative research, additional crosses were made for broadening resistance in soybean of early maturity groups, primarily II and III which are adapted to the Midwest area. Genetically diverse sources of resistance that have been identified at USDA-ARS, Jackson, TN, continue to be used in the crosses. PI507354 soybean line that is diverse from Peking, PI88788 and cv. Hartwig was crossed to elite cultivar IA1008 that was developed by collaborator from Iowa State University (ISU). Selections were made for soybean cyst nematode (SCN) resistance based on molecular markers and greenhouse screenings, and resistant progenies evaluated in preliminary yield trials at USDA-ARS, Jackson, TN, and further yield tests were conducted by ISU for release.