Genetic analysis and molecular mapping of stripe rust resistance genes in Chinese native wheat (Triticum aestivum) Lankao 5

Lankao 5 is a common wheat (Triticum aestivum) landrace collected from Henan province, China, which exhibits a high level of resistance to stripe rust (Puccinia striiformis f.sp. tritici, ‘Pst’) in field trials over many years. To analysegenetic of resistance in Lankao 5, F1 and F2 progenies were obtained from a cross between wheat genotypes Lankao 5 and Chinese Spring (CS). Parents, F1 and F2 plants, were planted in greenhouse and tested at the seedling stage with Pst races CYR29, CYR30, CYR31, CYR32, Sun11-4, and Sun11-11. Genetic analysis showed that the resistance of Lankao 5 to race CYR30 were conferred independently all by one dominant gene and one recessive gene, independently, resistance to Sun11-11 by one dominant gene, resistance to CYR31, CYR32, and Sun11-4 all by two independent dominant genes, and resistance to CYR29 by two recessive genes of independent action. Using F2 progenies from crosses between Lankao 5 and a set of 20 CS monosomic lines, the resistance gene in Lankao 5 to Pst race Sun11-11 was cytogenetically located on chromosome 7B. Using 141 F2 plants and their F3 generations with 7B specific simple sequence repeat (SSR) markers, a linkage map consisting of five SSR loci and the resistance gene locus YrLk was constructed. The linkage map spanned a genetic distance of 21.6 cM, and the SSR markers Xwmc396 and Xbarc267 were closely linked to YrLk with genetic distances of 3.3 and 4.4 cM, respectively. Analyses of chromosomal positions, reaction types to Pst race, and gene origin suggested that YrLk was very likely a novel resistance gene for stripe rust in wheat. Genetic analysis of the stripe rust resistance gene in Lankao 5 and closely linked markers for YrLk will facilitate the use of resistance in breeding programs to control wheat stripe rust.