Regeneration of Plantlet of Water Yam (Dioscorea oppositifoliaaL.) through In Vitro Culture from Nodal Segments

The present investigation was carried out with a view to regenerate plantlet of Dioscorea oppositifolia L through in vitro culture. Nodal vine segments from 45days old plants of field grown Dioscorea opositifolia were used as explants for initial culture. The explants were cultured on MS (Murashige and Skoogs, 1962) medium supplemented with different concentration and combination of cytokinines and auxines for primary shoot proliferation. The best shoot proliferation was observed in MS medium containing 2.0 mg-l KINETIN +1.0 mg-l BAP+0.5mg-l NAA + 100mg-l ascorbic acid where 90 % of explants showed proliferation with highest rate of shoot multiplication (10.5 shoots per explant). For rooting, the in vitro micro shootlets were inoculated on to the half-strength MS basal media supplemented with 2.0 mg/l NAA and rooting was more profuse with micro tubers in the base of the root primordia. Rooted shoots were transplanted in the green house for hardening and their survival rate was 90 % in the field condition.