A NULL GLI-D1 ALLELE WITH A POSITIVE EFFECT ON BREAD WHEAT QUALITY

The French wheat cultivar Darius (Da) has very good bread-making quality even though it possesses the high M(r) glutenin subunit combination 2, 7 and 12, which is associated with poor quality, and a null allele at the Gli-D1 locus. Darius was crossed with three cultivars, Corin (Cor), Capitole (Cap) and Courtot (Cou), ofpoor, medium, and good quality, respectively. The three progenies (Cor x Da, Cap x Da and Da x Cou) were used to investigate the genetic basis of the good quality of Darius. Gliadin and glutenin compositions were analysed by acid polyacrylamide gel electrophoresis (A-PAGE) and SDS-PAGE, respectively, from half F2 grains, and the quality was evaluated using six technological criteria for the corresponding plants. The high M(r) glutenin subunit alleles of Darius produced a negative effect on quality. The null allele of Darius, characterised by the absence of the Gli-D1 encoded omega-gliadins, was associated significantly with higher dough tenacity P, and strength W (up to 40% in the Cor x Da progeny). Darius had a higher amount of B zone low M(r) glutenin subunits than the three other cultivars. The null allele of Darius reduced the dough extensibility in the two first progenies, and probably increased the ratio of aggregated glutenin to unaggregated gliadins. These results demonstrated that using only one locus breeders can improve particular quality traits.