VARIATION AND CLASSIFICATION OF B-LOW-MOLECULAR-WEIGHT GLUTENIN SUBUNIT ALLELES IN DURUM-WHEAT

The B low-molecular-weight (LMW) glutenin subunit composition of a col lection of 88 durum wheat cultivars was analyzed. Extensive variation has been found and 18 different patterns were detected. Each cultivar exhibited 4-8 subunits, and altogether 20 subunits of different mobili ty were identified. The genetic control of all these subunits was dete rmined through the analysis of nine Fz populations and one backcross. Five subunits were controlled at the Glu-A3 locus, 14 at Glu-B3 and 1 at Glu-B2. At the Glu-A3 locus each cultivar possessed from zero to th ree bands and eight alleles were identified. At the Glu-B3 locus each cultivar showed four or five bands and nine alleles were detected. Onl y one band was encoded by the Glu-B2 locus. A nomenclature for these a lleles is proposed and the relationship between them and the commonly used LMW-model nomenclature is discussed.