Genome-Wide Association Study for Agronomic Traits in Wild Soybean (Glycine soja)

The agronomic traits of soybean are important because they are directly or indirectly related to its yield. Cultivated soybean (Glycine max (L.) Merr) has lost genetic diversity during domestication and selective breeding. However, wild soybean (G. soja) represents a useful breeding material because it has a diverse gene pool. In this study, a total of 96,432 single-nucleotide polymorphisms (SNPs) across 203 wild soybean accessions from the 180K Axiom((R)) Soya SNP array were employed in the association analysis. Wild soybean accessions were divided into four clusters based on their genetic distance using ADMIXTURE, principal component analysis, and neighbor-joining clusters. The linkage disequilibrium decayed rapidly in wild soybean. A genome-wide association study was conducted for days to flowering (DtF), days to maturity (DtM), the number of pods (NoP), and the 100-seed weight (100SW), which are major agronomic traits for wild soybean accessions. A total of 22 significant SNPs were found to be associated with DtF, DtM, and the 100SW. Based on the detected SNP markers, Glyma.12g210400, a gene related to DtF, Glyma.17g115300, a gene related to DtM, and Glyma.14g140200, a gene related to the 100SW, were selected as candidate genes. The SNP markers related to agronomic traits identified in this study are expected to help improve the quality of soybean cultivars through selective breeding.