Dominant Inheritance of a Trait Lacking β-conglycinin Detected in a Wild Soybean Line

Abstract

The QT2 Iine, which lacks β-conglycinin in the seed storage protein, was detected from our wild soybean germplasm collection. Although induced mutant lines lacking β-conglycinin were reported to be non viable in previous studies, the QT2 Iine grew normally and produced successive generations. To distinguish it from the non viable β-conglycinin-lacking line, this pheno-type was referred to as the “QT2-type”. In these studies, we investigated the mode of inheritance of the QT2-type and the genetic relationships between the QT2-type and some other soybean storage proteins. In spite of the fact that β-conglycinin was composed of three major subunits, genetic analysis of the QT2 Iine indicated that the QT2-type was controlled by one single dominant gene. The new genetic symbol of Scg was assigned to the QT2 type in this report. Furthermore, the mode of inheritance of the QT2-type was independent of that of the α'-subunit of β-conglycinin and seed lipoxygenases. The QT2-type hybrids, even without the presence of seed lipoxygenases, did not show any physiological abnormalities. These results indicate that the QT2 Iine is a suitable gene source to breed soybean varieties lacking β-conglycinin.