Identification of leaf rust resistance genes in Triticum species for transfer to common wheat
A total of 877 Triticum accessions (27 species) were screened for resistance to leaf rust (Puccinia recondita f. sp. tritici) using mixed inoculum of pathotypes UVPrt2, UVPrt3, UVPrtS, UVPrt9 and UVPrt13. Of these, 206 accessions were resistant/moderately resistant to all races. An attempt was made to cross each resistant accession with common wheat and to determine if resistance is expressed sufficiently in the presence of wheat genomes. Seventy nine accessions have not yet been crossed successfully, while the remaining 127 (representing 19 species) were crossed with common wheat. A number of transfer attempts failed in the F1 as a result of suppression of resistance (44 accessions) or formation of embryoless or non-viable seeds/seedlings (13 accessions). The resistance of 70 hybrids is fully expressed and these are now in various stages of back-crossing to wheat. The resistance was confirmed by retesting the species sources of the 70 successful combinations with the individual leaf rust pathotypes.