Assessment of the virulence level of powdery mildew populations affecting grains and grasses in Poland during 2015–2017

The study focused on the epidemiology and resistance of powdery mildew caused by Blumeria graminis f.sp. tritici in wheat crops in Poland from 2015 to 2017. Powdery mildew of cereals and grasses is a significant fungal disease globally, impacting crop yield and quality. The disease is favoured by moderate temperatures, high humidity, and poor air circulation. In Poland, it affects various regions, with differing intensities depending on environmental conditions. The research aimed to characterize the population structure of B. graminis f.sp. tritici and evaluate the effectiveness of resistance genes (gene Pm) against local pathogen populations. Leaf samples were collected from multiple locations in Poland across the study period. Single-spore isolates of B. graminis f.sp. tritici were obtained and inoculated onto a differential set of wheat varieties with known Pm genes to assess resistance levels. Statistical analyses revealed significant interactions between study years and Pm genotypes, indicating variability in resistance effectiveness across different environmental conditions. Genotypes such as Pm2, Pm2 + 4b + 8, Pm2 + 6, Pm4b + 5, Pm4b + 8, Pm5 + 8, Pm5d, Pm6, Pm7, and Pm8 consistently exhibited high resistance levels with low infection rates. In contrast, genotypes like Pm1 + 2 + 4b + 9 showed variable resistance, suggesting sensitivity to environmental factors or genetic interactions. The findings underscored the importance of monitoring pathogen populations and deploying effective Pm genes in breeding programs to enhance resistance durability. Strategies like gene pyramiding, which combines multiple Pm genes, were highlighted as effective approaches to mitigate disease impact under varying environmental conditions. In conclusion, the study provided critical insights into the dynamics of powdery mildew resistance in wheat in Poland, emphasizing the need for adaptive breeding strategies and continuous monitoring to combat evolving pathogen threats effectively.