In vitro Mass Propagation of an Epiphytic Orchid, Cymbidium aloifolium (L.) Sw., through Protocorm Culture

Aim: To develop a protocol for in vitro propagation of Cymbidium aloifolium, a threatened orchid highly used for medicinal purpose through protocorm culture.

Place and Duration of Study: Tissue culture Laboratory, Plant Biotechnology Unit, Department of Botany, Tribhuvan University, Kirtipur, Nepal, between November 2013 to December 2014.

Methodology: Small, green and globular protocorms with 0.1-0.3 cm diameter were subjected to grow individually on solidified Murashige and Skoog (MS) basal medium and MS medium supplemented with various concentration of plant growth regulators, 6-Benzylaminopurine (BAP, 0.5; 1; 1.5; 2 mg/l) or α-Naphthalene Acetic Acid (NAA, 0.5; 1 mg/l) or their combination. Six replicates were used for each concentration. The data for development of shoot and root from each protocorm culture were recorded in every two weeks for upto six month.

Results: Almost all conditions favoured multiplication but MS medium fortified with BAP (1 mg/l) and NAA (1 mg/l) resulted in maximum induction of rootless healthy shoots with an average value of 8-9 shoots per culture. On this medium, shoot multiplication was initiated after 9 weeks of culture whereas MS medium fortified with BAP (2 mg/l) and NAA (0.5 mg/l) was found to be most effective condition for the shoot multiplication along with well developed roots.

Conclusion: MS medium supplemented with high concentration of BAP and low concentration of NAA was found to be efficient for maximum multiplication of shoot and root. The in vitro developed healthy rooted plantlets of C. aloifolium were successfully acclimatized in green house on potting mixture containing cocopeat and moss in the ratio of 2:1. On this condition, nearly 70% of the plantlets were successfully survived. Hence, this protocol might be useful for mass propagation and ex situ conservation of this orchid through protocorm culture.