Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2007
Publication Date: July 1, 2007
Citation: Chen, X., Penman, L.N., Richardson, K.L. 2007. Races of Puccinia striiformis, the stripe rust pathogen in the United States in 2006. American Phytopathological Society Abstracts, San Diego, CA, 7/28-8/2/07, 97:S21. Technical Abstract: Puccinia striiformis causes destructive stripe rust on wheat and barley. Virulence changes in the pathogen populations can render previously resistant cultivars susceptible. In 2006, stripe rust occurred in over 20 states but the damage was the least for the last seven years mainly due to the widespread of dry weather. To identify new races and determine race frequencies, stripe rust samples from wheat and grasses were tested on a set of 20 wheat genotypes to differentiate races of P. striiformis f. sp. tritici (PST) and those from barley and grasses were tested on a set of 12 barley genotypes to differentiate races of P. striiformis f. sp. hordei (PSH). We identified 18 PST races and 11 PSH races, of which five PST and two PSH races were new. The most predominant PST race was PST-100 (virulent on Lemhi, Heines VII, Produra, Yamhill, Stephens, Lee, Fielder, Express, Yr8-AVS, Yr9-AVS, Clement, and Compair) with a frequency of 29.4%. Other predominant PST races were PST-114 (20.3%), PST-101 (16.8%), and PST-102 (11.9%), which all have the PST-100 virulences plus those on Moro and Tres, Chinese 166, and Tres, respectively. The most predominant PSH race was PSH-71 (Virulent on Topper, Emir, Hiproly, Varunda, Abed Binder 12, Trumpf, Mazurka, Bigo, and Bancroft) with a frequency of 25%. The results should be useful in choosing resistance genes for breeding programs.