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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetic Improvement of Wheat and Barley for Resistance to Biotic and Abiotic Stresses

Location: Wheat Genetics, Quality Physiology and Disease Research

Title: Genetic diversity for stripe rust Resistance in wheat landraces and identification of accessions with resistance to stem rust and stripe rust

Authors
item Sthapit, Jinita -
item Newcomb, Maria
item Bonman, John
item Chen, Xianming
item See, Deven

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 14, 2014
Publication Date: February 21, 2014
Repository URL: http://doi:10.2135/cropsci2013.07.0438
Citation: Sthapit, J., Newcomb, M.S., Bonman, J.M., Chen, X., See, D.R. 2014. Genetic diversity for stripe rust Resistance in wheat landraces and identification of accessions with resistance to stem rust and stripe rust. Crop Science. DOI: 10.2135/cropsci2013.07.0438.

Interpretive Summary: Stripe rust and stem rust are economically important diseases of wheat. Stripe rust continues to cause huge economic losses in major wheat growing regions with frequent emergence of new races of the pathogen. Wheat landraces from diverse geographic regions are a potential source of novel rust resistance genes. In search of multiple rust resistance, a total of 652 landrace accessions from 54 countries previously screened for resistance to stem rust pathogen (race Ug99) were tested for resistance to current races of stripe rust in Pullman and Mt. Vernon, WA. Of the accessions, 165 showed resistance to stripe rust in the field and 30 of them had resistance to stem rust as well. The landraces were genotyped with two types of genetic markers including 72 simple sequence repeats (SSR markers) and 8,633 single-nucleotide polymorphic (SNP) markers covering the whole wheat genome. Marker data was used to group the landraces based on genetic similarity and dissimilarity. Resistant landraces were grouped into different clusters suggesting that resistant genotypes are genetically diverse and are expected to possess diverse resistance genes. Genetically different landraces with resistance to stem rust and stripe rust have both global and regional importance as sources to develop new and diverse resistant germplasm.

Technical Abstract: Stripe rust, caused by Puccinia striiformis f. sp. tritici, and stem rust caused by P. graminis f. sp. tritici are economically important diseases of wheat. Stripe rust continues to cause huge economic losses in major wheat growing regions as new races of the pathogen frequently emerge. Wheat landraces from diverse geographic regions are a potential source of novel rust resistance genes. In search of multiple rust resistance, a total of 652 landrace accessions from 54 countries previously screened for resistance to stem rust pathogen (race Ug99) were tested for resistance to current races of stripe rust in Pullman and Mt. Vernon, WA. Of the accessions, 165 showed resistance to stripe rust in the field and 30 of them also had resistance to stem rust. The 652 landraces were genotyped with 72 SSR markers and 500 of them had data for 8,633 SNP markers covering the whole wheat genome. Genetic analysis based on SNP markers grouped the resistant landraces into nine different clusters in UPGMA dendrogram and three groups in PCA analyses, suggesting that resistant genotypes are genetically diverse and are expected to possess diverse resistance genes. Landraces with resistance to stem rust and stripe rust have both global and regional importance as sources to develop new and diverse resistant germplasm.

Last Modified: 11/26/2014
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