Stripe rust (Puccinia striiformis f. sp. tritici) resistance in wheat with the wheat-rye 1BL/1RS chromosomal translocation

Abstract

Wheat (Triticum aestivum) lines harboring the wheat-rye 1BL/1RS chromosomal translocation have become unpopular for genetic improvement as the disease resistance genes carried on the rye (Secale cereale) chromosome arm 1RS are no longer effective and the yield advantage has only been seen in certain genetic backgrounds. We have developed several wheat lines with the rye chromosome arm 1RS translocated from various rye inbreds. In this study, wheat cultivars or lines with the chromosome arm 1RS from the rye inbred line L155 or R12 were evaluated for reaction to races CYR31 and CYR32 of Puccinia striiformis f. sp. tritici prevalent in southwestern China. The wheat cultivars ‘Aurora’ and ‘Benno’, carrying the wheat stripe rust resistance gene Yr9, located on the 1BL/1RS translocation originally from the rye cultivar ‘Imperial’, were highly susceptible, whereas the wheat cultivars or lines ‘CN12’, ‘CN17’, ‘CN18’, R185, R205, and R212, with the chromosome arm 1RS translocated from the rye inbred line L155 or R12, were highly resistant. Results from genetic analysis indicated that the resistance was controlled by a single dominant gene located on the translocation chromosome 1RS. The resistance gene in ‘CN12’, ‘CN17’, and ‘CN18’ were temporarily designated as YrCN17, and the gene in R185, R205, and R212, as YrR212. Pedigree analysis showed that, although the resistance genes Yr9, YrCN17, and YrR212 originated from rye, both YrCN17 and YrR212 are effective in protecting wheat from high yield losses due to races CYR31 and CYR32 in China.