We assayed for Chrysanthemum stunt viroid (CSVd) in cultivated chrysanthemum (Chrysanthemum morifolium) collected from 10 prefectures in Japan and 8 wild species (Chrysanthemum spp.) cultivated at the National Institute of Floricultural Science (NIFS), Japan and determined complete nucleotide sequences of CSVd isolates infecting plants. CSVd was detected in 80 of 89 samples of cultivated chrysanthemum, and samples from all prefectures were infected. Since all 8 wild species had CSVd in RT-PCR

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... sults, they were recognized as hosts of CSVd, even though no stunt symptoms were observed. Five sequence variants of CSVd were distinguished among the 21 isolates based on the difference of the nucleotide sequences. Mutations were common in the P (pathogenicity) domain. Variant 5 from C. morifolium, and variant 4 from C. yoshinaganthum had different nucleotide sequences from those reported previously. Variant 1 was most frequently detected from samples in 6 prefectures and is assumed to be the predominant CSVd variant distributed in Japan.