Relationships Between Chromosome 1B-encoded Glutenin Subunit Compositions and Bread-making Quality Characteristics of Some Durum Wheat (Triticum turgidum) Cultivars

Abstract

Abstract The high and low Mr glutenin subunit compositions (controlled by the Glu-1 loci and the Glu-B3 locus, respectively) and the bread-making quality characteristics of 26 durum wheat (Triticum turgidum) genotypes were determined. The relationships between quality parameters and Glu-B1 and Glu-B3 controlled glutenin subunit composition were also investigated. The Glu-A1-controlled null allele was present in all the genotypes. High Mr subunits 20, 6 + 8 and 7 + 8 occurred in similar proportions in the cultivars analysed. The Glu-B3 low Mr allelic variants, LMW-1 and LMW-2, were both represented, with LMW-1 being present in lower proportion. Flour protein, SDS-sedimentation volume, dough strength (Alveograph W value), dough mixing time and bread loaf volume varied among the genotypes. Most samples had high Alveograph tenacity/extensibility (P/G) ratios, typical of tenacious gluten character. SDS-sedimentation volume, dough strength, dough mixing time and bread loaf volume were all interrelated. An association with flour protein content was observed only for mixing time, while the Alveograph tenacity/extensibility ratio was not correlated with the other parameters. Comparisons within the Glu-B1 and Glu-B3 loci indicated that the high Mr subunit 7 + 8 and the low Mr subunit LMW-2 had significantly greater beneficial effects on gluten strength and bread-making quality than the high Mr subunits 6 + 8 or 20 and the low Mr subunit LMW-1, respectively. High Mr subunit 6 + 8 had greater beneficial effects on quality than subunit 20.