Mapping stripe rust resistance gene YrSph derived from Tritium sphaerococcum Perc. with SSR, SRAP, and TRAP markers

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most devastating foliar diseases of common wheat (Triticum aestivum L.) worldwide. Growing resistant cultivars is the most effective approach to control the disease. To determine inheritance of stripe rust resistance and map the resistance gene in a common wheat line D31, developed from Triticum sphaerococcum Perc. (accession number AS348), F₁, F₂, and BC₁ progenies derived from the Taichung 29 × D31 cross were firstly inoculated with Chinese PST race CYR32 during whole growth stages under the field conditions. Genetic analysis indicated that the resistance to CYR32 in the line D31 was conferred by one recessive gene, temporarily designated as YrSph. A total of 400 simple sequence repeat (SSR), 315 pairs of sequence-related amplified polymorphism and 42 pairs of target region amplified polymorphism markers were screened, and four SSR markers and three TRAP markers were found to be polymorphic between the resistant and susceptible DNA bulks as well as their parents. Genetic linkage was tested on segregating F₂ population and indicated that all of the ten markers were linked to the resistance gene, two of which flanked the locus at 8.5 and 6.9 cM, respectively. The SSR markers mapped the resistance gene on chromosome arm 2AS. The results of chromosome location and pedigree analysis indicate that YrSph was probably a novel stripe rust resistance gene.