Characterization and Molecular Mapping of a Gene Conferring High-Temperature Adult-Plant Resistance to Stripe Rust Originally from Aegilops ventricosa

Wheat near-isogenic line AvSYr17NIL carrying , originally from for all-stage resistance to f. sp. , also shows nonrace-specific, high-temperature adult-plant (HTAP) resistance to the stripe rust pathogen. To separate and identify the HTAP resistance gene, seeds of AvSYr17NIL were treated with ethyl methanesulfonate. Mutant lines with only HTAP resistance were obtained, and one of the lines, M1225, was crossed with the susceptible recurrent parent Avocet S (AvS). Field responses of the F plants and F lines, together with the parents, were recorded at the adult-plant stage in Pullman and Mount Vernon, WA under natural f. sp. infection. The parents and the F population were phenotyped with a -virulent f. sp. race in the adult-plant stage under the high-temperature profile in the greenhouse. The phenotypic results were confirmed by testing the F population in the field under natural f. sp. infection. The F data indicated a single recessive gene, temporarily named , for HTAP resistance. The F lines were genotyped with Kompetitive allele-specific PCR markers converted from single-nucleotide polymorphism markers polymorphic between M1225 and AvS. The HTAP resistance gene was mapped on the short arm of chromosome 2A in an interval of 7.5 centimorgans using both linkage and quantitative trait locus mapping approaches. The separation of the HTAP resistance gene from should improve the understanding and utilization of the different types of resistance.