Genetic Association Analysis for the Discover of Calcium Content in Soybean Seeds.

The efficient utilization of soybean germplasm depends on the understanding of polymorphism and genetic distance among genotypes. In this study, genetic diversity was accessed among 54 North American and 51 Asian soybean genotypes including 52 large-seeded and 53 small-seeded lines. Sixty-five SSR primer pairs were used for genotyping purposes, representing 24 flanking markers for QTL associated with seed size, hardness, and calcium content and 42 selected core SSR markers. Results showed that the SSR loci produced an average of eight alleles and genetic diversity index of 0.72 among both small- and large-seeded accessions. Genetic distance within US and Asian accession was similar, indicating US food-grade soybeans had a relatively high level of genetic diversity. The high level of genetic diversity in food-grade soybeans may be attributed to diverse parentage and multiple selection criteria for specialty soybeans. In the cluster analysis, PIs from Asia tended to group together but were separate from US cultivars. However, adequate diversity is present in each type of the food-grade soybeans. These diverse germplasm may serve valuable gene pool for the development of conventional and specialty soybeans. Seed hardness and calcium content are important quality traits for small-seeded specialty soybeans. The association analysis of hardness and calcium content in these food-grade soybeans will be reported.