Mapping and validation of PCR-based markers associated with a major QTL for seed dormancy in wheat

Seed dormancy is one of the important factors controlling pre-harvest sprouting (PHS) resistance in wheat. We identified a major quantitative trait locus (QTL) for seed dormancy on the long arm of wheat chromosome 4A (4AL) via simple sequence repeat (SSR)-based genetic mapping using doubled haploid lines from a cross between Japanese PHS resistant variety ‘Kitamoe’ and the Alpine non-resistant variety “Münstertaler” (K/M). The QTL explained 43.3% of total phenotypic variation for seed dormancy under greenhouse conditions. SSR markers flanking the QTL were assigned to the chromosome long arm fraction length 0.59–0.66 on the basis of chromosome deletion analysis, suggesting that the gene(s) controlling seed dormancy are probably located within this region. Under greenhouse conditions, the QTL explained 28.5 and 39.0% of total phenotypic variation for seed dormancy in Haruyutaka/Leader (HT/L) and OS21-5/Haruyokoi (O/HK) populations, respectively. However, in field conditions, the effect was relatively low or not significant in both the K/M and HT/L populations. These markers were considered to be widely useful in common with various genetic backgrounds for improvement of seed dormancy through the use of marker-assisted selection. Further detailed research using near isogenic lines will be needed to define how this major QTL interacts with environmental conditions in our area.