Triticum aestivum - Triticum timopheevii introgression lines as a source of pathogen resistance genes

A collection of introgression lines was obtained from crosses of common wheat ( Triticum aestivum L.) cultivars with tetraploid wheat Triticum timopheevii (Zhuk.). Evaluation of resistance to fungal diseases re - vealed the lines with resistance to leaf and stem rusts, powdery mildew, spot blotch, and loose smut, the most widespread in Siberian region of Russia. Localization of the T. timopheevii genome fragments by means of microsatellite markers determined higher frequency of substitutions and translocations on chromosomes 1А, 2A, 2B, 5A, 5B and 6B. Molecular mapping of the loci determining leaf rust resistance revealed two independ - ent loci on chromosomes 5B and 2A. The major locus on 5BS.5BL-5GL translocated chromosome accounting 64% of the phenotypic variance of the trait was found to be closely linked to microsatellite markers Xgwm814 and Xgwm1257. The other, minor locus, controlling 11% of the trait was mapped next to Xgwm312 on chromo- some 2A. Microsatellite markers located near these genes may be used for controlling the transfer of valuable traits in new wheat cultivars.