In vitro propagation of Dioscorea alata var. purpurae.

Dioscorea alata var. purpurae (Indian purple yam) is an important source of diosgenin, a triterpenoid that is used as a raw material in the synthesis of corticosteroid hormones. These drugs are used for the treatment of pharmacological conditions such as arthritis. This paper reports in vitro propagation of explants of various parts of Dioscorea-tuber, leaves, and nodes. Murashige and Skoog media supplemented with hormones and additives was used to get maximum callus initiation and shoot/root induction. All the cultures were maintained at 25 ± 2 °C under cool-white fluorescent tubes with 16-h photoperiod. Callus initiation was observed from 8th to 11th day of inoculation, and subsequent root/shoot was initiated in nodal callus after 21 days. Hormones such as kinetin, indole-3-acetic acid, indole-3-butyric acid, α-naphthalene acetic acid, and thiadizuron did not show significant enhancement. Also, there was no need for supplementing additives (silver nitrate, glutamine, L-: asparagine monohydrate, polyethylene glycol). Combination of 6-benzylaminopurine (0.2 ppm) and 2,4-dichlorophenoxyacetic acid (2 ppm) hormones gave the best results, and all parts of the plants gave similar callus induction.