Race and Virulence Dynamics of Puccinia triticina in China During 2000-2006

Wheat leaf rust, caused by Puccinia triticina, is an important foliar disease of wheat in China. The dynamics of races and virulence in P. triticina populations in China during 2000 to 2006 were studied. Leaf rust samples were collected during surveys of wheat fields and trap nurseries in 16 provinces, and provided by coworkers throughout China. The virulence of single-pustule isolates was determined on near-isogenic Thatcher lines for leaf rust resistance genes Lr1, Lr2a, Lr2c, Lr3, Lr9, Lr16, Lr24, Lr26, Lr3ka, Lr11, Lr17, and Lr30, and races were denominated using the Prt code system. During 2000 to 2006, 79 races were identified from a total of 613 isolates. Races PHT (23.7%), THT (14.7%), PHJ (11.4%), and THJ (4.2%) were the four common races, all avirulent to Lr9 and Lr24. The frequency of isolates with virulence to Lr1, Lr2c, Lr3, Lr11, Lr16, Lr17, and Lr26 was over 80%, and these isolates were widely distributed in China, whereas the frequencies of virulence to Lr9, Lr19, Lr24, Lr25, Lr28, and Lr29 were 0.2 to 2.5%. The diversity of virulence phenotypes of Chinese P. triticina populations appeared to increase from 2000 to 2006. P. triticina races and virulences in China appear to be isolated from those in other countries.