2023 Volume 65 Pages 35-41
To investigate QoI fungicide resistance in wheat powdery mildew in Aichi Prefecture, this pathogen was collected from six local wheat production areas in 2021 and examined for its sensitivity to a QoI (azoxystrobin) using bioassays and mutations in cytb. Results demonstrated that there were strains resistant to azoxystrobin harboring the G143A mutation in cytb. Furthermore, quantitative allele-specific PCR (ASqPCR) was performed to identify resistant- and sensitive-type alleles in cytb, and both alleles were successfully quantified. In 2022, strains were collected from 24 sites, and their resistance and sensitivity were determined by ASqPCR. Strains with resistant-type alleles were widely distributed in the prefecture. The ratio of resistant- and sensitivity-type alleles was further characterized. This is the first scientific report in Japan to quantify the distribution of QoI fungicide resistance in wheat powdery mildew within a specific region.
