EVALUATING SEED GERMINATION AND FLOWERING IN TISSUE-CULTURED DENDROBIUM OVATUM LINDL PLANTLETS

The genus Dendrobium is one of the most important genera with distribution of eleven species in the Western Ghats, belonging to the family Orchidaceae. It is known for its long lasting, showy flowers which has significance in floriculture industry. Dendrobium ovatum Lindl. Is an epiphytic orchid found in the Western Ghats? A rapid in vitro seed germination technique is described here. MS, VW, B5 and KC media supplemented with various concentrations of auxins and cytokinins were used in combination for asymbiotic seed germination and plantlet formation. In the evaluation of the media VW medium supplemented with 2 mg BAP/L-1 and NAA 5mg/L-1 is found to be suitable. Further hormonal concentrations of auxins and cytokinins were evaluated for a minimal and optimal level in the medium. VW basal medium fortified with 10 mg NAA/L-1 and 2 mg BAP/L-1 and 50 ml. CM induced formation of PLBs which further differentiated into plantlets. In the optimization process for phytohormones, 0.5 mg BAP/L-1 and 5 mg NAA/L-1 favoured maximum number of plantlet formation. However, rhizogenesis was found to be minimal in the above medium. In vitro rooting was successful with VW medium supplemented with IAA 2mg/L-1, 0.5 mg BAP/L-1, CM 50 ml, and 500mg of activated charcoal. 90 days old in vitro plantlets inside the tissue culture bottles were seen with inflorescence production with 10-12 flowers per axis. Hardened plants were transferred to green house after ex vitro rooting technique. Significance of the present work is discussed here.