RFLP mapping of the three major genes, Vrn1, Q and B1, on the long arm of chromosome 5A of wheat

Chromosome 5A of wheat carries several major genes of agronomic importance, including Vrn1 controlling spring/winter wheat difference, Q determining spike morphology and B1 inhibiting awn development. A population of single-chromosome recombinant lines from the cross between two chromosome substitution lines, 'Chinese Spring' (Cappelle-Desprez 5A) and 'Chinese Spring' (Triticum spelta 5A) was developed to map these genes on the long arm of chromosome 5A relative to RFLP markers. Using 120 recombinant lines, a map of approximately 230 cM in length was constructed. The gene order was centromere– Vrn1– Q– B1. The Vrn1 locus was tightly linked to two RFLP markers, Xbcd450 and Xrz395 with 0.8 cM, and to Xpsr426 with 5.0 cM. The Vrn1-adjacent region was located in the central of the long arm, approximately 90 cM from the centromere. The chromosome region around Q and the 5A/4A translocation break-point were mapped by three RFLP markers, and their order was found to be Q– Xpsr370– Xcdo457–4A/5A break-point– Xpsr164. The B1 locus was located on the most distal portion of the long arm. This revised version was published online in July 2006 with corrections to the Cover Date.