Abstract:

New virulent race’s occurrence and development are dominant factors of stripe rust disease outbreak and breakdown of resistance to stripe rust in wheat cultivars. In this paper, 1966 wheat stripe rust samples, which were collected from different regions in Gansu Province from 2004 to 2009, were detailedly studied through routine monitoring, pathogenicity test, antivims spectra analysis and so on. Here 37 races and pathotypes were detected; that basically reflected the changes of dominant pathotypes and physiologic races in Gansu during this period. Except for ‘CYR33’ as well as ‘CYR32’ as parallel first dominant races with frequency of 24.1% in 2005, ‘CYR33’ is always the first dominant race during 2004~2009 together with the frequencies of 29.3%, 26.2%, 33.5%, 38.0% and 21.5%, respectively, while ‘CYR32’ was the second dominant race. Total frequencies of these two races were varied from 37.5% to 57.1%. The third and fourth dominant races were respectively ‘shuiyuan 11-4’, ‘shuiyuan 11-7’, ‘shuiyuan 11-5’ and ‘CYR31’ during 2004-2006, ‘shuiyuan 11-7’ (IIS), ‘shuiyuan 11-7’ in 2007, and ‘CYR33’ (anti-F) and ‘shuiyuan 11-4’ in 2008, with the frequencies of 4.1%~11.6%. Whereas in 2009, ‘CYR33’ (anti-F, frequency 18.9%) and ‘shuiyuan 4’ (anti-F) were the second and fourth dominant races, respectively. And other races had lower frequencies. Total frequencies of Hybrid46 and shuiyuan 11 pathotypes rapidly increased from 93.1% in 2004 to 99.4% in 2008. Wheat stripe rust had entered into a new stage of predominant Hybrid46 (represented by ‘CYR33’ and ‘CYR32’) and shuiyuan 11 pathotypes. And ‘CYR32’, ‘CYR33’, Yr9, Yr3b+4b and YrSu were the dominant races and pathotypes. This will significantly affects on stock compositions of our national wheat stripe rust, and provides scientific basis for wheat rust-resistant breeding and control.