We identified a novel mutant line lacking an α-subunit. The line was obtained by subjecting to gamma-ray irradiation Kari-kei 434, a genetically fixed line with a low level of β-conglycinin which is characterized by the absence of the α '-subunit and low levels of both the α -and β-subunits of β -conglycinin, one of the major soybean storage pro-teins. The mutant line which lacks both the α - and α '-subunits went through two generations without displaying any physiological abnormalities. We concluded that the induced trait characterized by the lack of the α -subunit is truly inherited.