Stripe Rust Resistance in the Wheat Cultivar Jagger is Due to Yr17 and a Novel Resistance Gene

Yellow rust, also known as stripe rust, is caused by Puccinia striiformis Westend. f. sp. tritici Eriks (PST) and is one of the most common and persistent wheat (Triticum aestivum L.) diseases worldwide. A mapping population of recombinant inbred lines from the cross of 'Jagger' (moderately resistant) x '2174' (moderately susceptible) was tested at three sites in Washington where predominant races PST-114 and PST-116 naturally occurred, at Rossville, KS, where PST-100 was inoculated, and in Beijing, China, where a predominant Chinese stripe rust race CYR32 was inoculated on adult plants. A major quantitative trait locus for adult-plant stripe rust resistance was located on the short arm of chromosome 2A (QYr.osu-2A), where Jagger was found to carry markers for resistance gene Yr17 from Aegilops ventricosa Tausch (syn. Triticum ventricosum). Therefore, Yr17 is likely the resistance gene on chromosome 2A in Jagger. Markers for Yr17 were found to occur frequently in cultivars from the southern Great Plains but only occasionally in cultivars from other U.S. wheat regions. A novel resistance gene was mapped on the long arm of chromosome 5A (QYr.osu-5A), for which the Jagger allele showed consistent resistance to multiple races of the stripe rust pathogen. A significant genetic effect of the resistance gene Lr34/Yr18 from 2174 was detected only when the population was tested with CYR32 in China.