Genetic Diversity and Association Analysis of Protein and Oil Contents in Food-grade Soybean.

Food-type soybean has generated tremendous public interests in various soyfoods including tofu, soymilk, natto, bean sprouts, and edamame due to their nutritional value and health benefits. Much of the breeding progress is dependent on availability of genetic variation in agronomic and seed quality traits. The genetic diversity and association analysis were performed among 105 food-type soybean genotypes using 65 simple sequence repeat (SSR) markers distributed on 20 molecular linkage groups (MLGs).  Based on the SSR marker data, the 105 soybean genotypes were divided into three clusters and further clustered into six groups.  A negative correlation was obtained between protein and oil contents (r = -0.67).  Thirteen SSR markers distributed on 11 MLGs were identified to be significantly associated with oil content (p < 0.001 and R²% = 14.4 – 43.5) and 19 SSR markers distributed on 14 MLGs with protein content (P < 0.001, R²% = 14.3 – 45.6). Results from this research will be helpful for breeders to use marker-assisted selection in food-type soybean breeding and facilitate genetic mapping of protein and oil contents in soybean.