Development of PCR-based markers for a high grain protein content gene from Triticum turgidum ssp dicoccoides transferred to bread wheat

Grain Protein Content (GPC) of wheat (Triticum aestivum L. and T. turgidum L.) is important for improved nutritional value and is also one of the majo r factors affecting breadmaking and pasta quality. A quantitative trait loc us (QTL) for high GPC was detected a few years ago in the short arm of chro mosome 6B from accession FA15-3 of Triticum turgidum L. var, dicoccoides. N ew molecular markers are presented here to facilitate the transfer of this high GPC gene into tetraploid and hexaploid wheat cultivars. Two sets of PC R (polymerase chain reaction) primers were designed to amplify regions of t he non-transcribed spacer of the XNor-B2 locus. This Locus was selected bec ause it mapped on the peak of the QTL for GPC. The first pair of allele-spe cific primers produced an amplification product only when the T. turgidum v ar. dicoccoides XNor-B2 allele was present. The second pair of primers ampl ified fragment(s) of similar length in the different genotypes that after d igestion with the restriction enzyme BamHI allowed differentiation of the T . turgidum var, dicoccoides allele. Four microsatellites markers were mappe d on the short arm of chromosome 6B at both sides of the QTL peak and two o n the long arm. Five additional amplified fragment length polymorphism (AFL P) markers were mapped into the QTL region on 6BS. These PCR markers togeth er with 10 restriction fragment length polymorphism (RFLP) markers showed t hat the hexaploid cultivar Glupro, selected for high GPC, carries a distal segment of chromosome 6BL and a proximal segment of 6BS from dicoccoides ac cession FA15-3 encompassing the segment with highest LOD score for the GPC QTL.