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

Abstract

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 tauschii and 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.