EN
The study investigates the chemotherapeutic effect of plant growth regulators in eradicating mixed infection with Cymbidium mosaic (CyMV) and Odontoglossum ringspot viruses (ORSV) from Cattleya schönbrunnensis x C. leopoldii gutata. The experiment was designed to test a range of concentrations of 6-benzylaminopurine, kinetin and zeatin added to the basal medium on proliferating Cattleya mericlones. The results indicate that to eliminate CyMV from tissue cultures the best protocol for adding plant growth regulators was induction with 3.2 mg l-1 kinetin added to modified MS medium and then further propagation on 0.2 mg l-1 zeatin. This treatment was advantageous in terms of micropropagation. Micropropagation on basal medium supplemented with 5.0 mg l-1 BA after induction with 0.5 mg l-1 zeatin also effectively eliminated CyMV from cultures of the Cattleya hybrid. Infection with ORSV virus persisted in all treatments.