1a.Objectives (from AD-416)
Screen untaggeed germplasm lines for resistance to Phomopsis seed decay (PSD) of soybeans. Breed high-yielding resistant cultivars and germplasm lines for North Central and southern U.S. soybean production regions by incorporating new resistant genes and alleles. Develop new and rapid screening tools that are correlated with the field screening method for measurement of plant resistance.
1b.Approach (from AD-416)
Use field and laboratory approaches to identify sources of Phomopsis resistance.
During the first year of this project, 123 selected soybean germplasm lines collected from 28 countries, and breeding lines and cultivars from Southern U.S. will be screened in the fields of three states (Arkansas, Mississippi, and Missouri). Visual scoring and seed assay in laboratories on the incidence of the PSD pathogen will be performed. The top 10-15 resistant lines will be selected for the second year field trials with replicated inoculation and non-inoculation tests using local isolates from each state. Winter nursery facilities in Argentina and Costa Rica contracted by the University of Arkansas will be available to the team to speed up the process of generation advances. Mapping populations will be developed and molecular markers will be identified for use in marker-assisted selection.
The objectives of this research are to screen germplasm for resistance to Phomopsis seed decay (PSD); to breed high-yielding resistant cultivars and germplasm lines for North Central and Southern U.S. soybean production regions by incorporating new resistance genes and alleles; and to develop new and rapid screening tools that are correlated with the field screening method for the measurement of plant resistance. This project started on April 1, 2009. By June 15, 135 selected soybean germplasm lines (original plan was to include 123 PI lines but we added 12 lines for additional resistant and susceptible checks) representing 28 worldwide origins and MG3-5 maturities have been planted in the fields in three states: including Arkansas; Mississippi, and Missouri. We will perform seed assays to identify sources of resistance for PSD.