Genome-Wide Association Studies of Soybean Seed Hardness in the Chinese Mini Core Collection

Soybean seed hardness is an important quality character in soybean food processing. Both vegetable soybean and natto require soft seeds to achieve a desirable sensory experience and for effective processing. In this study, we used a texture analyzer to measure the seed hardness of Chinese mini core collection via two indexes over 4years and found significant correlations among the seed hardness, seed oil content, and germplasm eco-region. Based on 1514 SNPs, genome-wide association studies (GWAS) were conducted using a mixed linear model (MLM). Seventeen SNPs were identified to be associated with seed hardness in at least two environments. Among them, one locus, designated Q-15-0087770, was associated with two indexes, and 13 putative genes were confirmed based on their annotations in SoyBase. This research provides new insights into advanced marker-assisted selections for breeding soybeans for seed hardness and oil content.