Screening Fast-Neutron Soybean Lines for Seed Composition Traits

Mutagenesis has been a useful tool in many crop species to create heritable genetic variability for trait improvement and gene discovery. In this study, fast neutron (FN) radiation was used to induce mutations for studying genes that effect soybean seed composition. Phenotypic screening of the FN population at the University of Minnesota has revealed mutant lines with modified seed protein, oil, and sucrose levels. Seven mutant lines with promising seed composition traits were outcrossed to four University of Minnesota elite cultivars and subjected to bulked segregant analysis (BSA). For mutant population R29C32, a significant marker for increased oil was found on chromosome 10 near a known deletion. A backcross population was developed to validate this association. Markers were developed, and plants homozygous for the deletion revealed significantly greater (p<0.05) oil and significantly less protein compared to segregating plants not having the deletion or heterozygous for the deletion. A similar BSA approach is underway to characterize a wide array of interesting seed composition phenotypes including lines with significantly increased sucrose levels. These studies will identify novel marker trait associations and provide molecular markers to be used in breeding programs.