VIRUS-FREE Phalaenopsis PRODUCTION USING INFECTED STOCK PLANTS

Ribavirin (virazole) was used in association with in vitro cultivation of flower stem nodes of Phalaenopsis stock plants co-infected with the Cymbidium mosaic virus (CymMV) and the Odontoglossum ringspot virus (ORSV). Nodes were grown in Ichihashi medium, which is specific formulated for growing Phalaenopsis, with minor alterations such as containing 5 mg/L BAP and 1 mg/L NAA (pH 5.5). Four Ribavirin concentrations were tested (0, 10, 30, and 50 ppm/L), with three repeats. The presence of the viruses was evaluated using DAS-ELISA on days 240, 330, and 380 into in vitro cultivation. CymMV-negative plants were obtained only with treatments with Ribavirin 30 and 50 ppm/L. The results obtained at the end of the experiment (day 380) show that 50 ppm/L Ribavirin was the most efficacious treatment, with 56.67% of CymMV negative plants, while the 30-ppm/L dose led to 16.67% of CymMV-negative plants. No treatment eliminated ORSV. The comparison of results shows that chemotherapy with Ribavirin was able to obtain CymMV-free plants, and that the drug is efficient against only this virus.