Identification of Chrysanthemum Genetic Resources Resistant to White Rust Caused by Puccinia horiana

This experiment was carried out to identify genetic resources of chrysanthemum wild species and commercial cultivars that are resistant to white rust disease caused by Puccinia horiana. A total of 190 chrysanthemum accessions, composed of 11 accessions belonging to six wild species and 179 commercial cultivars, were screened for resistance to P. horiana isolates collected from Muan and Jeonju, the main production area of chrysanthemum in Korea. A total of 41 spray cultivars and three wild species (Chrysanthemum boreale, C. yoshinaganthum, and C. zawadskii) were identified as resistant. Nine standard and 28 spray cultivars with poorly developed chlorotic lesions and pustules on the leaves were moderate resistant. The remaining 18 standard, 83 spray cultivars and three wild species (Aster spathulifolius, C. indicum, and C. pacificum) were highly susceptible. The use of resistant cultivars is one of the most efficient approaches for overcoming white rust disease in chrysanthemum cultivation. Therefore, these genetic resources can be used in crossbreeding programs for developing white rust resistant chrysanthemum cultivars.