qTaHa-5DL: another major QTL regulating wheat grain hardness.

Grain hardness has important effects on grain quality and the end-use of wheat. In this study, a collection of 103 common wheat germplasms and a DH population of 194 lines were used to identify new quantitative trait loci (QTL) for grain hardness. Two stable genetic loci on chromosome 5D were detected under different locations and years with one of them being the Ha locus on 5DS where the major gene Puroindolines for wheat grain hardness is located. Another locus of qTaHa-5DL also showed a significant impact on grain hardness index (HI) with HI increasing from ~ 20 to ~ 45 and hardness type changing from soft to mixed when Puroindolines are wild type. A kompetitive allele-specific PCR (KASP) marker for qTaHa-5DL was developed and the effectiveness of the QTL was confirmed in 184 breeding lines with the marker K-Ha5DL dividing wheat into two distinct categories. This new QTL can be effectively used to select soft or medium hard wheat.