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Poster: Biology & Disease Mgmt: Genetics of Resistance


Molecular mapping of effective stripe rust resistance genes in wheat germplasm PI 182126
X. CHEN (1), J. Feng (2), M. Wang (3) (1) USDA-ARS and Washington State University, U.S.A.; (2) Department of Plant Pathology, Washington State University, U.S.A.; (3) Department of Plant Pathologist, Washington State University, U.S.A.

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most damaging diseases of wheat. Spring wheat landrace PI 182126, originally from Sind, Pakistan, has shown a high level of resistance to stripe rust in field experiments for more than 10 years and in greenhouse tests with several predominant races. The objective of this study was to map the resistance gene(s) in PI 182126. A population of 120 F5 recombinant inbred lines was developed from the cross between PI 182126 and susceptible genotype Avocet S through single-seed decent. The population was tested with US predominant races PSTv-14 and PSTv-37 at seedling stage under greenhouse conditions and at adult-plant stage in fields under natural infection of the pathogen near Pullman and Mount Vernon, Washington in 2014. The population was genotyped using microsatellite markers. Two resistance genes were mapped to chromosomes 5B and 7B. Using Chinese Spring nulli-tetrasomic and 7B deletion lines, the gene on 7B was mapped to the 0.14 bin of the long arm. Based on the chromosomal location, tightly linked markers, and effective throughout growth stages against all races tested, the gene on 7B is different from Yr39, Yr52, Yr59, YrZH84, and YrC591 previously mapped to the long arm of chromosome 7B, and is useful for diversifying stripe rust resistance genes used in breeding programs.