Transfer of rust resistance from Aegilops ovata into bread wheat (Triticum aestivum L.) and molecular characterisation of resistant derivatives

An interspecific cross was made to transfer leaf rust and stripe rust resistance from an accession of Aegilops ovata (UUMM) to susceptible Triticum aestivum (AABBDD) cv. WL711. The F-1 was backcrossed to the recurrent wheat parent, and after two to three backcrosses and selfing, rust resistant progenies were selected. The C-banding study in a uniformly leaf rust and stripe rust resistant derivative showed a substitution of the 5M chromosome of Ae. ovata for 5D of wheat. Analysis of rust resistant derivatives with mapped wheat microsatellite makers confirmed the substitution of 5M for 5D. Some of these derivatives also possessed one or more of the three alien translocations involving 1BL, 2AL and 5BS wheat chromosomes which could not be detected through C-banding. A translocation involving 5DS of wheat and the substituted chromosome 5M of Ae. ovata was also observed in one of the derivatives. Susceptibility of this derivative to leaf rust showed that the leaf rust resistance gene(s) is/are located on short arm of 5M chromosome of Ae. ovata. Though the Ae. ovata segment translocated to 1BL and 2AL did not seem to possess any rust resistance gene, the alien segment translocated to 5BS may also possess gene(s) for rust resistance. The study demonstrated the usefulness of microsatellite markers in characterisation of interspecific derivatives.