Assessing stem rust tolerance in commercial wheat varieties: Insights from field trials in Kazakhstan

This study provides the first comprehensive assessment of stem rust tolerance in commercial wheat varieties from Kazakhstan and Russia, including spring and winter varieties. Field trials were conducted to compare yield and agronomic traits between stem rust-inoculated and fungicide-treated plots, providing a practical framework for assessing tolerance. Key indicators such as disease severity, area under the disease progress curve, thousand kernel weight, and the stress tolerance index were evaluated to gauge variety resilience under stress. Significant variations in tolerance were observed, with varieties such as 'Pamyat' 47', 'Nadezhda', 'Lyubava 5', 'Tselinnaya 3s', 'Severyanka', 'Egemen-20', 'Zhemchuzhina Povolzh'ya', 'Dimash', 'Serke' and 'Korona' maintaining yield potential despite high disease pressure. Correlations revealed that traits such as flag leaf area, vegetative period, and plant height were associated with greater tolerance, highlighting their potential in breeding. With the expected increase in stem rust outbreaks due to climate change and the evolving virulence of stem rust pathogens, these findings emphasise the need for breeding programs incorporating resistance and tolerance, offering a sustainable alternative to fungicide use. This study provides critical insights for breeders and plant pathologists seeking to enhance wheat resilience in regions prone to rust epidemics.