Chrysanthemum Stunt Viroid, a Disease of Large-flowered Chrysanthemum in Niigata Prefecture

Abstract

A disease of large-flowered chrysanthemum plants with characteristic stunting symptoms was observed in Niigata Prefecture in 1988. Chrysanthemum stunt viroid (CSVd) was transmitted from those plants by grafting onto 'Mistletoe', and it was confirmed by electrophoretic analysis of nucleic acid. Although it has been reported that CSVd-infected spray-type chrysanthemum flowered up to 2 weeks earlier than the non-infected, CSVd-infected chrysanthemum cultivars used in this study flowered 1 to 2 weeks later with bearing anemone-type abnormal shaped flowers. In the cultivar 'Senryoumusume', CSVd was not detected from the winter rosette sucker of infected plants in 50 to 61% of plants tested. Subsequent assays indicated that by vegetative propagation during a period of low temperature, CSVd could be eliminated. We found that sap transmission rate was different among varieties tested and that CSVd was not transmissible to healthy plants from infested soil. After RT-PCR amplification of CSVd, a 354 nucleotide sequence was determined which is comparable with that of the English and Australian types.