Preventing extinction and improving conservation status of Vanilla borneensis Rolfe-A rare, endemic and threatened orchid of Assam, India

Vanilla borneensis Rolfe is considered as a rare, endemic and threatened terrestrial climbing orchid of Assam, India. The plant is restricted to only two pockets of Assam with a poor population size. Therefore, conservation of this plant through proper scientific investigation is urgently needed. The present study has as its objectives to study the distribution, standardization of suitable macropropagation methods for reinforcement and reintroduction in suitable wild habitat, as determined by ecological niche modelling (ENM) for the purposes of conservation. For improving the conservation status of the species, potential area and habitat for reintroduction was determined using maximum entropy (MaxEnt) distribution modelling algorithm. Seed germination under natural conditions was found to be very poor for which a macropropagation protocol was standardized; plantlets were raised and reinforced to locations where the population size is very small i.e., mean density, frequency of occurrence and abundance in relation to other associated species was 17.77, 14.16 and 0.82 respectively. Macropropagation method standardized here through cutting was found to be more efficient in terms of time and cost. Application of 100 ppm indole -3- butyric acid (IBA) and 40 ppm naphthalene acetic acid (NAA) significantly improved rooting traits. Further, survival rate was measured significantly very high at 73% while 1000 numbers of V. borneensis plantlets were transferred to the field. Present study has improved the population and conservation status of V. borneensis. (C) 2017 Elsevier GmbH. All rights reserved.