Meristem tip culture of Dendrobium orchid for boosting efficiency of hygienic large scale micropropagation

Abstract

Orchids are among the most important economic ornamental crops in Thailand. Many varieties of orchids are grown for export as cut flowers and pot plants. Clonal propagation is normally used for large-scale production. However, this might enhance the dissemination of diseases. In particular, virus is easily widespread through vegetative transplanting organs. There are two common viruses which cause severe problems in orchid production in Thailand and other countries worldwide. These are Cymbidium mosaic potexvirus (CymMV) and Odontoglossum ringspot tobamovirus (ORSV). The production of virus-free orchid plantlets is necessary for the elimination of the viral disease invasion in orchid farms. Several techniques have been tried but until now no appropriate method has been developed for achieving disease-free plants for commercial-scale production. However, using the meristem tip culture technique seemed to be efficient for conducting disease-free orchid cultures. Meristem tips were aseptically dissected from apical shoots of Dendrobium orchid plants under the stereomicroscope. Thereafter, they were cultured in liquid VW media containing either 15% (by volume) coconut water or 0.1-1.0 mg L-1NAA. Then the selection of CymMV and ORSV-free clones was efficiently achieved by using RTPCR technique. Afterwards, selected virus-free clones were multiplied and plantlets were regenerated. The advantages of this protocol technique are a reduction of contaminants, a shorter time period for tissue culture and increased plant hygiene.