Race composition and genetic diversity of a f. sp. population from Yunnan and Guizhou epidemiological regions in China in 2018.

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Wheat stripe rust, caused by f. sp. (), is an extremely destructive wheat disease worldwide. Yunnan and Guizhou provinces are the main overwintering regions for and inoculum sources for the disease in China. Surveillance of race dynamics of the population is essential for managing the disease in local and other wheat-growing regions of China. However, population dynamics in this region is not monitored yearly. In this study, a population of 113 isolates from Yunnan and Guizhou in 2018 were phenotyped on the two wheat differential sets and analyzed by 12 simple sequence repeat (SSR) markers. As a result, 25 races were identified from the population on Chinese differentials and predominant races was CYR32 with a frequency of 17.70%. None of the isolates was virulent to and Only a few isolates showed virulence to and differentials Zhong 4. The Kosman index () of the population was 0.292 on the Chinese differentials, and 0.274 on single gene lines and additional differentials, respectively. In total, 64 MLGs were detected among 113 isolates and the expected heterozygosity () was 0.424. A close genetic relationship was detected between Lufeng (Yunnan) / Nayong (Guizhou), Fuyuan (Yunnan) / Bijie (Guizhou), and Shizong (Yunnan) / Xingyi (Guizhou). This study provided useful information on population structure and virulence to genes in the Yunnan and Guizhou epidemiological regions, and will be used to guide the control of wheat stripe rust and targeted wheat breeding in this region.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s42161-022-01273-1.