Comparative RFLP mapping of Triticum monococcum genes controlling vernalization requirement

The adaptability of Triticum aestivum to a large range of environments is partially due to genetic differences in sensitivity to vernalization. The most potent gene reducing the vernalization requirement in hexaploid wheat is Vrn-A1. An orthologous vernalization gene, designated Vrn-A(m)1, was mapped in the diploid wheat Triticum monococcum between RFLP markers Xwg908 and Xabg702 on the long arm of chromosome 5A(m)L. The orthology of VrnA(m)1 with Vrn-A1 (5A wheat, originally Vrn1), Vrn-D1 (5D wheat, originally Vrn3), Vrn-R1 (5R rye, originally Sp1) and Vrn-H1 (5H barley, originally Sh2) was shown by mapping RFLP markers linked to these vernalization genes on the T. monococcum linkage map. A second vernalization gene, designated Vrn-A(m)2, was found in the distal region of chromosome 5A(m)L within a segment translocated from homoeologous group 4. This gene is completely linked to RFLP marker Xbcd1402 and located between the same RFLP markers (X beta-Amy-1 and Xmwg616) as the Vrn-H2 (originally Sh) locus in Hordeum vulgare.