Development of a green soybean line with a green cotyledon and a tetra null genotype for P34, lectin, Kunitz trypsin inhibitor, and lipoxygenase proteins

Soybean (Glycine max (L.) Merr.) varieties with a green seed coat and cotyledon have long been cultivated for their high levels of lutein, which is considered beneficial for eye health. However, mature soybean seeds also contain major antinutritional and allergenic factors, including P34, Kunitz trypsin inhibitor (KTI), lectin, and lipoxygenase proteins. The objective of this research was to develop a new soybean line with a green cotyledon and a green seed coat, and without P34, KTI, lectin, and lipoxygenase proteins. A breeding population was developed using two cultivars and three germplasms. Seventy-four F2 seeds with a green cotyledon and a green seed coat were obtained. Twenty-four F2 seeds with a tetra null genotype (p34p34-titi-lele-lox1 lox1lox2lox2lox3lox3) were selected and planted in a greenhouse. One F2 plant that exhibited suitable agronomic traits was selected. The SDS-PAGE and western blot methods were used to determine the absence (tetra null genotype) of P34, KTI, lectin, and lipoxygenase proteins in random F3 seeds from the F2 plant selected. The color of the cotyledon and seed coat for the new selection line was green. The stem height was 72 cm and the 100-seed weight was 21.5 g. The new line obtained in this research could be bred into a soybean variety with a green cotyledon, a green seed coat, and fewer allergenic and antinutritional properties.