The Korean Journal of Crop Science 한국작물학회지 ISSN:0252-9777(Print) 2287-8432(Online)

Soybean is the one of the most important crops for providing quality vegetable protein to umans and livestock. Soybean cultivars with a brown seed coat have a wide range of antioxidant benefits because of the flavonoid components. However, they also contain lectin, 7S α′ subunit, lipoxygenase, and Kunitz trypsin inhibitor (KTI) proteins that can be allergenic and digestive inhibitors and reduce processing aptitude. Genetic removal of these four proteins is necessary in soybean breeding. Therefore, this study was conducted to select a new line with brown seed coat, green cotyledon, and tetra-null genotype (lecgy1lox1lox2lox3ti) for lectin, 7S α′ subunit, lipoxygenase, and KTI proteins in the mature seed. Five germplasms were used to create breeding population. From a total of 58 F₂ plants, F₂ plants with lele genotype were selected using a DNA marker, and F₃ seeds with a brown seed coat, green cotyledon, and the absence of 7S α′ subunit protein were selected. Three lines (S1, S2, and S3) were developed. Genetic absence of lectin, 7S α′ subunit, lipoxygenase, and KTI proteins was confirmed in F₆ seeds of the three lines, which had a brown seed coat, green cotyledons, and a white hilum. The 100 seed weights of the three lines were 26.4-30.9 g, which were lower than 36 g of the check cultivar - ‘Chungja#3’. The new S2 line with 30.9 g hundred seed weight can be used as a parent to improve colored soybean cultivars without antinutritional factors such as lectin, 7S α′ subunit, lipoxygenase, and KTI proteins.