Molecular Mapping of Quantitative Trait Loci for Stripe Rust Resistance in Wheat Landrace PI 622129

Wheat stripe rust, caused by the biotrophic fungal pathogen Puccinia striiformis f. sp. tritici (Pst), is among the top crop diseases incurring huge economic losses worldwide. Identification of new stripe rust resistant sources that can be easily used in wheat cultivar development is essential for food security. PI 622129, an Iranian wheat landrace, exhibits high resistance to the predominant U.S. Pst races. A recombinant inbred line (RIL) population from the cross PI 622129 × Stardust was genotyped using SNPs generated by genotyping-by-sequencing. The RIL population was evaluated for responses to the Pst race PSTv-37 at the seedling stage in three environments, and quantitative trait loci (QTL) analysis revealed four QTL for stripe rust resistance on chromosome arms 2DS, 5BS, 2AL, and 7BL. Of these, QYr.stars-2DS and QYr.stars-5BS are major QTL explaining 21-38% and 11.6-27.2% of the total phenotypic variance, respectively, in three experiments. QYr.stars-2DS is a new stripe rust resistance locus that was identified in the interval of 2.58-5.54 Mb on chromosome arm 2DS based on the Chinese Spring IWGSC RefSeq v2.1 reference genome. Another QTL, QYr.stars-5BS, is close to Yr47 and was delimited to the interval 8.1 – 9.0 Mb in the reference genome. QYr.stars-2AL and QYr.stars-7BL were mapped to the terminal and QTL-rich regions on chromosome arms 2AL (750.8 – 752.5 Mb) and 7BL (718.1 – 721.2 Mb), respectively. KASP markers were developed to facilitate the rapid introgression of these QTL into locally adapted lines via marker-assisted selection.