Development and Characterization of Novel Wheat-Rye 1RS•1BL Translocation Lines with High Resistance to Puccinia striiformis f. sp. tritici

Wheat-rye 1RS center dot 1BL translocations from 'Petkus' rye have contributed substantially to wheat production worldwide with their great disease resistance and yield traits. However, the resistance genes on the 1RS chromosomes have completely lost their resistance to newly emerged pathogens. Rye could widen the variation of 1RS as a naturally cross-pollinated related species of wheat. In this study, we developed three new 1RS center dot 1BL translocation lines by crossing rye inbred line BL1, selected from Chinese landrace rye Baili, with wheat cultivar Mianyang11. These three new translocation lines exhibited high resistance to the most virulent and frequently occurring stripe rust pathotypes and showed high resistance in the field, where stripe rust outbreaks have been most severe in China. One new gene for stripe rust resistance, located on 1RS of the new translocation lines, is tentatively named YrRt1054. YrRt1054 confers resistance to Puccinia striiformis f. sp. tritici pathotypes that are virulent toward Yr9 and YrCn17. This new resistance gene, YrRt1054, is available for wheat improvement programs. The present study indicated that rye cultivars may carry additional untapped variation as potential sources of resistance.

Automated summary

The wheat-rye translocations from 'Petkus' rye have contributed significantly to wheat production worldwide. However, the resistance genes on these translocations have lost their effectiveness against new pathogens. In this study, new translocation lines with high resistance to stripe rust were developed by crossing rye with wheat. A new gene, named YrRt1054, was identified in these lines and showed resistance to some virulent stripe rust pathotypes. This study suggests that rye cultivars could be valuable sources of untapped resistance variation.