Genetic and physical mapping of photoperiod insensitive gene Ppd-B1 in common wheat

Photoperiod response is a major determinant of duration of growing stages in wheat. Conscious selection for these photoperiod response genes in plant breeding programs will yield genotypes with better adaptation to diverse environments. To provide a starting point for the development of molecular markers useful for the selection process, genetic maps around the photoperiod insensitive gene Ppd-B1 were built employing three segregating populations. Of 25 markers that were selected for the Ppd-B1 region, only two could be mapped across all three populations. In pairwise comparisons, the extent of transferable markers ranged from three to eight. Recombination frequencies of markers distal to Ppd-B1 were more homogeneous than those of proximal markers. This finding suggested a closer proximity of Ppd-B1 to the markers that were mapped distal to breakpoint 0.83 in the physical map of chromosome 2BS.