Indexing and production of virus-free chrysanthemums

Chrysanthemum morifolium cv. Regol Time plants were found to be infected with Chrysanthemum B carlavirus (CVB). They were made CVB-free by using meristem tip culture, chemotherapy and thermotherapy. The plants were indexed by biological assay, double antibody sandwitch enzyme linked immunosorbent assay (DAS-ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR). The maximum number of virus-free plants (26.7 %, as indexed by RT-PCR) was obtained with 2-thiouracil at 0.04 g dm-3 concentration. Only 12 % plants were found to be virus-free, after being kept at 38 °C for 30 d. For indexing CVB in chrysanthemums, RT-PCR was found to be the most reliable method