Genetic study of seed sugar content in diverse soybean germplasm

Inheritance of low-stachyose content in the genotype V99-5089 was evaluated using 152 F2:3 lines derived from V97-3000 x V99-5089. Genetic relationships between the low-stachyose gene in V99-5089 and a low-stachyose gene found in PI 200508 were studied using 126 F2:3 lines derived from PI 200508 x V99-5089. Stachyose content was determined by a HPLC system, and range of the parents and previously reported stachyose content for wild-type soybean were used to classify high- and low-stachyose lines. Results showed a single recessive gene conferring low stachyose content in V995089 which is non-allelic to the one reported in PI 200508. A total of 24 genotypes with different compositional traits and 21 plant introductions with unique sugar profiles were studied for soluble sugar content stability under different environments. Genotype-by-environment interaction effect was significant for all sugars. However, genotypes with extreme sugar contents tended to be stable across environments. All five sugars presented high heritabilities (r = 0.80 to 0.98). Sucrose and stachyose were negatively correlated (r = -0.67 to -0.84); stachyose and raffinose were positively correlated (r = 0.37 to 0.49); calcium was negatively correlated with sucrose (r = -0.30 to -0.46) and raffinose (r = -0.43 to -0.47). Sucrose was positively correlated with seed size (r = 0.32 to 0.61) and negatively correlated to calcium (r = -0.30 to -0.46). The information from this study will be valuable to breeders in developing value-added soybeans for food and feed uses.