Promising strategy for eliminating chrysanthemum Chlorotic Mottle Viroid in chrysanthemum ‘Glory Pink’

Chrysanthemum chlorotic mottle viroid (CChMVd) significantly challenges chrysanthemum production, necessitating effective eradication strategies. Therefore, this study aims to evaluate the efficacy of chemotherapy (ribavirin), electrotherapy, and their combination to eliminate CChMVd in chrysanthemum ‘Glory Pink.’ Shoot tips were identified as more effective explants than axillary buds owing to their lower viroid concentrations. Electrotherapy reduced CChMVd amount in regenerated shoots but failed to completely eradicate the viroid. Chemotherapy with ribavirin (30 mg · L -1 ) and the combined treatment effectively eliminated CChMVd in new shoots from subculture, with the combined approach resulting in higher viroid-free rates (50% and 100% from axillary buds and shoot tips, respectively), confirmed via nested polymerase chain reaction (PCR). Quantitative real-time PCR analysis further revealed the absence of CChMVd in nested PCR-negative shoots. Moreover, there is no genetic variation in the nested PCR-negative shoots derived from the combined treatment. These findings emphasize the synergistic efficacy of combining chemotherapy and electrotherapy, supported by reliable diagnostic methods, in controlling CChMVd and promoting sustainable chrysanthemum cultivation.