Influence of the Salix caprea Genotype and Leaf Characteristics on the Occurrence of Fungus Melampsora caprearum

Leaf rust caused by Melampsora caprearum is one of the most important but understudied diseases of goat willow (Salix caprea). This research studied for the first time the effect of genotype and the morphology of goat willow leaves on the occurrence and abundance of Melampsora caprearum uredinia. The genotype showed a statistically significant impact on the occurrence and abundance of uredinia on goat willow leaves. The morphological characteristics of the leaves, leaf area, leaf circumference, and length and width of the leaves had a statistically significant effect on the occurrence of uredinia, while they did not impact the uredinia abundance on the leaves. On the same tree, leaves of larger dimensions showed greater resistance to the occurrence of infection symptoms. Based on leaf morphology, the results represent a realistic basis for selecting goat willow trees less susceptible to Melampsora caprearum. Measures that can be applied in goat willow habitats to regulate leaf dimensions and reduce damage from Melampsora caprearum are discussed.