Relationship between gliadin alleles and dough strength in Italian bread wheat cultivars

Dough strength, as determined by Alveograph W, was studied in Italian bread wheat cultivars grown at several locations over 21 years of testing. Broad sense heritability of Alveograph W was found to range between 0.40 and 0.82, variation in this parameter being affected by genotype x year interactions. Standardised Alveograph W values (Wst) across 40 environments (location-year combinations) were computed for 54 cultivars with reference to the long-term control (cv. Mec), and a quality score based on the Wst value was given to each gliadin allele occurring in at least four of the 54 cultivars analysed. Significant differences in Wst values were observed at the Gli-B1, Gli-B2 and Gli-A2 loci. Alleles Gli-B1b, Gli-B2c and Gli-A2b were significantly related to high gluten strength. An overall quality score based on allelic composition at these loci explained 41% of the observed Wst variation in the 54 cultivars used for the score definition, and 23% to 48% of W value variation in three sets of independent data. The combination of this score with a quality score based on Glu-l alleles coding for high M-r glutenin subunits could explain, on average, about 50% of gluten strength variation. (C) 1997 Academic Press Limited.