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Oral: Risk Assessment


Association between temperature sensitivity and virulence of Blumeria graminis f. sp. tritici
Y. ZHOU (1), L. Han (1), Y. Zou (1), X. Duan (1), J. Fan (1) (1) Institute of Plant Protection, Chinese Academy of Agricultural Sciences, China

Wheat powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt) is a highly destructive disease in China, which is highly sensitive to meteorological factors, especially temperature. In order to clarify the co-evolution between temperature sensitivity and virulence of Bgt, we collected a total of 90 isolates from 5 provinces (cities), including Yunnan, Sichuan, Beijing, Henan and Shaanxi, and tested the virulence of isolates according to 32 wheat varieties or lines with known powdery mildew resistant genes and sensitivities to temperature by detached leaf segment method. The results showed that the mean ET50 of tested isolates was 23.22°C, with the highest 25.15°C and lowest 19.78°C, respectively. The ET50 value of 73.34% of isolates ranged from 22.0°C to 24.0°C, and 10% of isolates below 22°C, 16.67% of isolates above 24°C. The virulence gene diversity index of the 90 Bgt isolates was 0.2370. The highest index H of isolates which from Sichuan Province is 0.2212 while the lowest index H of isolates from Henan Province is 0.1975. The results showed that there was a significant negative correlation between temperature-sensitivity and virulence diversity of B. graminis f. sp. tritici populations.