Map location of the HvCbf3 gene. A, PCR reactions were performed on genomic DNA from wheat cv Chinese Spring (CS), barley cv Betzes (BB), and six wheat-barley disomic addition lines (carrying 2H, 3H, 4H, 5H, 6H, or 7H) using HvCbf3 gene-specific primers (see “Materials and Methods”). Amplified DNAs were electrophoresed in a 1.2% (w/v) agarose gel. B, The genotypes of each HvCbf3 gene in the barley cv Dicktoo × barley cv Morex mapping population were compared with mapping data (available at http://wheat/pw.usda.gov/ggpages/DxM/dmsor.txt). The map location of HvCbf3 genes is boxed. The dark bar on chromosome 5H indicates a quantitative trait locus (QTL) for vernalization requirement and freezing tolerance (Pan et al., 1994). The same region of wheat chromosome 5A (Galiba et al., 1995; Vagujfalvi et al., 2000) is compared with barley chromosome 5H. Units are in cM.