In vitro propagation of endemic wild edible yams of Western Ghats – the hotspot of global biodiversity and its conservation in India

Abstract

North-Eastern Himalayas and Western Ghats are two hot spots of global biodiversity, showcasing the rich diversity in wild relatives of root and tuber crops, especially Dioscorea. Fifty different species of Dioscorea are reported from India, of which 44% are endemic and 16 of them occur in the southern Western Ghats. The Central Tuber Crops Research Institute (CTCRI) being the National Active Germplasm Site (NAGS) for tropical tuber crops addresses issues like collection/augmentation, characterization, evaluation, conservation, exchange and breeding work on yams. 5175 yam accessions consisting of 50 species including 231 accessions of wild Dioscorea collected from different agro-climatic regions of India are conserved here. The present investigation focuses on the in vitro propagation studies of eight endemic wild edible yam species, with distribution in the southern Western Ghats. These species are ethnically important as secondary staple among the local tribal population. Protocols were standardized for rapid clonal multiplication of these species through nodal segment culture, direct organogenesis as well as in vitro bulbil induction, which facilitated multiplication of true to type plants and dissemination of these valuable wild clonal materials to national programmes and their conservation. In vitro bulbil induction was achieved in the non-bulbil bearing species which is an excellent tool for conservation and international exchange programmes. Cytokinins (BAP/Kin/TDZ) alone or in combination proved best for direct de novo shoot organogenesis. Successful rooting and hardening with 85-94% survival of regenerants with underground tuber development enabled us to design effective management and conservation strategies for their sustainable utilization in crop improvement programmes.