Fine Mapping and Validation of a Major QTL for Gluten Strength.

Gluten strength plays an important role in determining the end product quality of durum wheat semolina. Using a population developed from a cross of ‘Rugby’ (low gluten cultivar) and ‘Maier’ (high gluten cultivar), a stable and major QTL (QGs.ndsu-1B) contributing up to 90% of the phenotypic or 93% of the genotypic variation was detected on 1BS.The alleles for increased gluten strength at this locus were contributed by Maier, the high gluten parent. The initial QTL mapping identified this QTL in a 7.3 cM region flanked by a DArT converted STS marker sts-wPt2395, and a SSR marker wmc85. For fine mapping of this locus, a large F₂ population (~8,000 seeds) was developed from the cross of Rugby and Maier. Initial screening of 1,504 F₂ plants using two flanking markers identified a total of 144 recombinants for this region. These recombinants are being genotyped using 90k SNP Infinium assay, for fine mapping of this locus. In addition, a panel of 64 durum wheat cultivars was also used for gluten strength evaluation in multiple environments. This panel is also being genotyped using the same assay and will be used for validation as well as fine mapping of QGs.ndsu-1B. The availability of closely associated markers with this locus may prove invaluable for marker-assisted selection of gluten strength as well as for the introgression of this trait into other durum wheat varieties.