Introgression of the Glu-A1t allele encoding high molecular weight glutenin subunits A1x21* and A1y21* into winter bread wheat varieties.

We applied DNA-based marker-assisted selection to introduce the rare Glu-A1t allele into winter bread wheat (Triticum aestivum) and provided the first validation of the Glu-A1t DNA markers for varieties adapted to Northern European conditions. The allele has earlier only been screened in spring wheat using protein analysis. The Glu-A1t allele encodes a unique pair of high molecular weight glutenin subunits (HMW-GSs), with both A1x21* and A1y21* being expressed. This allele has shown potential for improving bread-making quality and increasing grain protein content in bread wheat. Four molecular markers (the indel marker Xid3, the STS marker Axnull, and two KASP markers Mk-A1-1-12 and Mk-A1-1-13) were validated for their ability to detect Glu-A1t and distinguish it from other GLU-A1 alleles (a, b, c). These markers were used for creating hybrid winter wheat lines, which can be used for evaluating the effects of Glu-A1t on yield and baking quality. Genotyping results were fully consistent with SDS-PAGE analysis of HMW-GS composition, confirming the presence of both A1x21* and A1y21* subunits in F3 hybrids. Overall, this study delivers a novel set of validated molecular tools and genetic resources that can be directly applied in breeding programs aimed at improving wheat baking quality in Northern Europe.