Fine Mapping of a Novel Heading Date Gene, TaHdm605, in Hexaploid Wheat

The heading date is critical in determining the adaptability of plants to specific natural environments. Molecular characterization of the wheat genes that regulate heading not only enhances our understanding of the mechanisms underlying wheat heading regulation but also benefits wheat breeding programs by improving heading phenotypes. In this study, we characterized a late heading date mutant, m605, obtained by ethyl methanesulfonate (EMS) mutation. Compared with its wild-type parent, YZ4110, m605 was at least 7 days late in heading when sown in autumn. This late heading trait was controlled by a single recessive gene named TaHdm605. Genetic mapping located the TaHdm605 locus between the molecular markers cfd152 and barc42 on chromosome 3DL using publicly available markers and then further mapped this locus to a 1.86 Mb physical genomic region containing 26 predicted genes. This fine genetic and physical mapping will be helpful for the future map-based cloning of TaHdm605 and for breeders seeking to engineer changes in the wheat heading date trait.