Breeding a black soybean line with green cotyledon free from lectin, KTI, P34, lipoxygenase, and stachyose

Black soybeans with green cotyledon have long been widely consumed in the East due to their high content of health-promoting anthocyanins and lutein. However, major anti-nutritional and allergenic components such as lectin, Kunitz trypsin inhibitor (KTI), P34, lipoxygenase, and stachyose are contained in mature seed. The objective of this research is to breed a soybean line with a black seed coat, a green cotyledon, and the penta null genotype (lele-titi-p34p34-lox1lox1lox2lox2lox3lox3-rs2rs2) for all five components. The F₂ plant strain with penta null genotype for lectin, KTI, P34, lipoxygenase, and stachyose components was developed. The breeding line has purple flower, determinate growth habit, brown pod, black seed coat and green cotyledon. The stem height of the breeding line was 57.0 cm and 100 seed weight was 31.5 g. This is the first soybean breeding line with black seed coat, green cotyledon and penta null genotypes for lectin, KTI, P34, lipoxygenase, and stachyose factors. This line will be used as parent to improve a black soybean cultivar with green cotyledon that have significantly reduced anti-nutritional and allergenic traits.