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ARS Home » Pacific West Area » Pullman, Washington » WHGQ » Research » Publications at this Location » Publication #322620
Title: Races of Puccinia striiformis f. sp. tritici in the United States in 2011 and 2012 and comparison with races in 2010

Author
item WAN, ANMIN - Washington State University
item Chen, Xianming
item YUEN, JONATHAN - Uppsala University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/8/2015
Publication Date: 5/1/2016
Citation: Wan, A., Chen, X., Yuen, J. 2016. Races of Puccinia striiformis f. sp. tritici in the United States in 2011 and 2012 and comparison with races in 2010. Plant Disease. 100(5):966-975.

Interpretive Summary: Stripe rust is one of the most important diseases on wheat in the United States. In 2011, severe wheat stripe rust caused extensive application of fungicides in the western U. S., and the disease was more widespread and caused more yield loss in the eastern U. S. in 2012. In this study, we characterized virulences and identified races of the pathogen by testing stripe rust samples collected throughout the U. S. in 2011 and 2012 on a set of 18 wheat lines, each with a single resistance gene. In 2011, 35 races were identified from 349 viable samples collected from 19 states of the U. S. and Ontario province of Canada. The frequencies and distributions of the races were determined and compared with those in 2010. The total of 55 races identified from 2010 to 2012 in the U. S. were clustered into two major virulence groups, and dynamics of predominant races were presented and discussed. This information is useful for making decisions when screening wheat germplasm for developing stripe rust resistant wheat cultivars and managing the disease by growing cultivars with effective resistance.

Technical Abstract: Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most important diseases on wheat in the United States. In 2011, severe wheat stripe rust caused extensive application of fungicides in the western U. S., and the disease was more spread and caused more yield loss in the eastern U. S. in 2012. In this study, we characterized virulences and identified races of Pst by testing the stripe rust samples collected throughout the U. S. in 2011 and 2012 on the set of 18 Yr single-gene differentials. In 2011, 35 races were identified from 349 viable samples collected from 19 states of the U. S. and Ontario province of Canada with PSTv-11 (35.5%), PSTv-37 (12.6%), PSTv-14 (11.8%), PSTv-4 (5.4%), and PSTv-34 (3.4%) as the top five predominant races. In 2012, 23 races were identified from 341 viable samples collected from 24 states of the U. S. and Ontario of Canada with PSTv-37 (47.5%), PSTv-11 (11.7%), PSTv-14 (10.0%), PSTv-52 (9.4%), and PSTv-48 (4.4%) as the top five predominant races. Nationally, PSTv-37, PSTv-52, and PSTv-34 were most widely distributed, while PSTv-11, PSTv-14, PSTv-4, and PSTv-48 were mostly detected in the western U. S. High frequencies (>80%) were detected for virulences to Yr6, Yr7, Yr8, Yr9, Yr17, Yr27, Yr44, and YrExp2; moderate frequencies (20-80%) for virulences to Yr1, Yr43, YrTr1, and YrTye; low frequencies (<10%) for virulences to Yr10, Yr24, Yr32, and YrSP; and virulences to Yr5 and Yr15 were not detected, indicating that these two genes are still effective against the Pst population in the U. S. The total of 55 races identified from 2010 to 2012 in the U. S. were clustered into two major virulence groups, and dynamics of predominant races and virulence frequencies for the three years were presented and discussed. The information should be useful for screening wheat germplasm for developing stripe rust resistant wheat cultivars and managing the disease by growing cultivars with effective resistance.