TRANSFER OF A GENE FOR STEM RUST RESISTANCE FROM TRITICUM-ARARATICUM TO HEXAPLOID WHEAT

A partially dominant gene for seedling resistance to Puccinia graminis f.sp. tritici was transferred from two accessions of Triticum araraticum (PGR 6126 and PGR 6195) to hexaploid wheat by a series of backcrosses. This gene confers an intermediate level (infection type 1+ to 2) of resistance to a large number of P. graminis isolates. Because of linkage with the genes Lr13 (1.0%), Lr23 (4.7%), Lr16 (34.4%), Sr36 (21.9%) and the Sr9 (28.0%) locus, this gene is probably on the short arm of chromosome 2B. It has been assigned the symbol Sr40. No apparent deleterious quality characteristics were associated with the transfer of Sr40. This gene is being combined with the closely linked gene Lr13. This recombinant line should be useful in wheat breeding. The concurrent attempt to transfer resistance to P. recondita from T. araraticum to hexaploid wheat was not successful.