Characterization and Molecular Mapping of a Stripe Rust Resistance Gene in Synthetic Wheat CI110

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Psi), is one of the most destructive diseases of wheat (Triticum aestivum L.). To diversify stripe rust-resistant resources for wheat breeding programs, a CIMMYT synthetic wheat line CI110 was identified to be resistant to 28 isolates of Pst, including 6 Chinese prevalent races CYR28-CYR33. Genetic analysis indicated that a single dominant gene was responsible for the stripe rust resistance in CI110, temporarily designated YrC110. A molecular map, harboring YrC110 and 9 linked SSR markers, was constructed through simple sequence repeat (SSR), and bulked segregant analysis. These linked markers and YrC110 were assigned on the short arm of chromosome 1B using the Chinese Spring nullisomic-tetrasomic and ditelosomic stocks. Gene postulation based on seedling reaction patterns to 30 Pst isolates suggested that the resistance gene YrC110 seemed different from the other known resistance genes tested, such as Yr9, Yr10, Yr15, Yr24, and Yr26/YrCH42. Four SSR markers Xbarc187(150), Xgwm18(227), Xgwm11(223), and Xbarc240(292) distinguished YrC110 from Yr10, Yr15, Yr24, and Yr26/YrCH42, and could be used as diagnostic ones for YrC110 in wheat resistant breeding programs against stripe rust.