Effects of spring wheat cultivar resistance on leaf and Fusarium head blight diseases and deoxynivalenol content in Lithuania

Fungal diseases represent a major threat to wheat, causing significant quantitative and qualitative grain yield losses. The use of fungicides is an important factor that provides a high level of disease control, helps increase crop yields, and ensures stability of production, but environmental and health risks necessitate foundational strategies for fungal disease management. One of them could be use of resistant cultivars. A field experiment was conducted over four growing seasons (2016-2019). Six spring wheat cultivars were evaluated to assess the effects of cultivar resistance on disease severity. Cultivar resistance significantly influenced disease outcomes: powdery mildew area under the disease progress curve (AUDPC) values ranged from 68.04 to 342.28, while tan spot ranged from 45.03 to 163.44. These results showed that the choice of less susceptible varieties could significantly reduce disease severity by 72.4-80.1%. Fusarium head blight indexes (FHBi) ranged from 0.03 to 13.62%, showing a 99.8% difference between extreme cultivars. A moderate positive correlation (p < 0.01) was observed between the FHBi and the percentage of Fusarium-infected kernels (FIK), while FIK and deoxynivalenol (DON) contamination showed only weak correlation. The effectiveness of fungicides varied by cultivar, with sensitive cultivars showing higher yield responses (+24.6%) than disease resistant cultivars (+13.5%). These results demonstrate that strategic cultivar selection can substantially reduce disease impact while optimizing chemical inputs. • The less susceptible varieties significantly reduce diseases severity • In years with higher disease severity, differences in sensitivity to FHB were clearly visible and showed significant variation between the resistant and the susceptible cultivars • The most resistant cultivar to foliar diseases recorded the highest DON concentration in grain • The fungicides were less effective on the more higher-yielding cultivars