Variance in leaf spot susceptibility in chestnut trees of different species and hybrids

Abstract

Prior to the first occurrence of chestnut blight in 1976, leaf spot caused by Cylindrosporium castaneae was one of the most important diseases of European chestnut trees in Slovakia. In 2011, extensive damage of leaves by leaf spot was recorded in young chestnut trees in an experimental chestnut orchard in Príbelce, Slovakia, where seedlings and grafts of different species and hybrids (Castanea sativa, Castanea crenata, and C. sativa × C. crenata) exhibited visible differences in the extent of leaf spot. Morphological observations of the fungal species causing leaf spot were conducted, and the disease symptoms were described. Digital images of particular leaves were evaluated using Quick Micro Photo software, and the ratio of infected leaf area was calculated. Trees species showed a significant effect on the proportion of leaf spot area, indicating that the response to fungal attacks has a strong genetic determinism, with resistance being clearly influenced by species. The lowest leaf spot infection was recorded in C. crenata seedlings.