Inheritance and molecular mapping of leaf rust resistance gene in hexaploid wheat Synthetic 45

To contain the infection of newly evolved leaf rust virulence(s), diverse source of germplasm need to be explored for identification of novel genes. In order to exploit wild resources, CIMMYT has developed a series of synthetic hexaploid wheat (SHW) by combining the accessions of D genome donor Triticum tauschiiand T.durum. In the present study, Synthetic 45, was evaluated for effectiveness of its resistance against diverse leaf rust pathotypes. Mode of inheritance of resistance to understand the nature of genetics and molecular mapping to locate its chromosomal position were studied. Characterization of leaf rust resistance in Synthetic 45 by multi-pathotype tests showed a high degree of seedling resistance to 20 diverse pathotypes of leaf rust pathogen and adult plant resistance against two most prevalent pathotypes, 77-5 and 104-2. Inheritance studies showed that resistance in Synthetic 45 was governed by a single recessive gene. Molecular mapping and linkage with microsatellite markers, Xwmc432 and Xcfd15 have indicated that the resistance gene is located on short arm of 1D chromosome with 6.1 cM distal to Xwmc432 and 10.6 cM to Xcfd15 with 4.6 cM distance among the two markers. The gene identified in Synthetic 45 has been tentatively designated as LrSyn45.