Effects of Wheat Cultivar Mixtures on Population Genetic Structure of Puccinia striiformis f. sp. tritici

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive wheat diseases worldwide. Understanding the effects of cultivar mixture on disease control and population genetic structure of Pst could promote the effective application of cultivar mixtures. This study designed nine cultivar mixtures composed of different component cultivars with field experiments in Zitong County, Sichuan Province in two seasons from 2016 to 2018. Diseased leaves were collected in each plot of treatment in the spring and, in total, 835 and 568 isolates were obtained and genotyped with 10 pairs of simple sequence repeat markers in the 2 years, respectively. The observed and theoretical values of the area under the disease progress curve (AUDPC), wheat yield, Pst genotypic diversity, and the frequency of Pst dominant genetic groups were compared among cultivar mixtures. With the 2 years' experiments, there were three and two cultivar mixtures, respectively, showing significant effect on the relative reduction of AUDPC; there were no significant effects on the relative yield increase in all mixtures in the 2 years. There were four and five cultivar mixtures showing positive effects on the relative increase of Pst genotypic diversity in the 2 years, respectively. Moreover, all cultivar mixtures could decrease the frequencies of Pst dominant genetic groups on highly susceptible component cultivar compared with their theoretical frequencies. (c) 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.