Multiple shoot induction and regeneration of Vanilla borneensis Rolfe - a critically endangered orchid of Assam, India

In the present investigation, a micropropagation protocol has been developed for Vanilla borneensis Rolfe – a critically endangered orchid through multiple shoot regeneration. Through in vitro multiple shoot regeneration from both nodal and shoot tip explants, maximum (100%) shoot induction was observed. The minimum time required for shoot bud induction was observed from the shoot tip (5–7 days) on medium supplemented with BAP (4.44 mM) + KIN (2.32 mM) as compared to the nodal explants. Maximum multiple shoot regeneration was observed from nodal explants on the medium supplemented with BAP (4.44 mM) + TDZ (6.82 mM). However, maximum shoot length was observed on the medium supplemented with BAP (4.44 mM) + 15% CW and the number of nodes (5.27±0.33) per shoot after 90 days. Maximum (80-100%) of root initiation was observed in almost all the concentrations of NAA. The shortest time of root initiation was found on the medium supplemented with NAA (5.37 mM). Further, acclimatization period was found to be 15 days with 70% acclimatization while 60% of survivability was observed in the field condition. This efficient micropropagation method of V. borneensis could be successfully used for mass propagation as well as conservation of the critically endangered wild orchid.