Micropropagation of Dioscorea alata L. through nodal segments

Yams (Dioscorea) are well known for their medicinal use as well as nutritional values. Dioscorea plants are rapidly vanishing from nature due to their over-exploitation by human beings. In order to conserve Dioscorea plants, the present investigation was carried out with a view to regenerate plantlet of Dioscorea alata L. through in vitro culture using full strength Murashige and Skoog (MS) medium and indole-3-acetic acid (IAA) with and without sucrose. Nodal vine segments of D. alata were used as expiants and nodal segments were cultured on MS (Murashige and Skoog's) medium supplemented with different concentrations of auxin (IAA) for axillary bud proliferation. Best shoot proliferation was observed in MS medium containing 1.5 mg/L kinetin + 2 mg/L IAA with highest rate of shoot multiplication (average of 9.90 shoots/explants). Micro shootlets were inoculated in half strength MS basal medium supplemented with different concentrations (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mg/L) of IAA and best rooting was observed in medium supplemented with 2.5 mg/L IAA with highest root length (8.14 cm). Regenerated plants were transplanted in hardening medium containing Brick bats + Charcoal + Dried moss + Leaf molds + Soil in 1: 1: 1:1:1 proportion. Maximum survival percentage was observed as 85 to 87% after one month of transfer in hardening medium. This work proposes an economic technique for the conservation of D. alata.