Callus Induction and Regeneration of Dioscorea alata L.

Using aseptic seedings of Dioscorea alata L., effects of various exogenous hormones, materials, and light conditions on the callus induction and differentiation of the stem-segments with nodes of D.alata were studied.The following results were obtained.(1) There was no significant difference on the callus induction between the applications of 6-BA and KT.The hormone combination most conducive to the stem callus induction was either KT 2 mg·L^-1+NAA2 mg·L^-1 or 6-BA 2 mg·L^-1+NAA 2 mg·L^-1.(2) The callus induction rates of different explants differed significantly on a same medium.For example, on the MS medium containing 6-BA 2 mg·L^-1+NAA 2 mg·L^-1, the rate of bulbil induction was 91.167%;that of stem, 86.300%;and, that of leaf, considerably lower at 45.167%.(3) By addition of activated carbon at 0.25 g·L^-1 to MS medium, browning of the calluses was significantly alleviated and the induction rate higher than the others.(4) Although there was no significant difference in the callus induction rate of the stems under light and darkness, the stems calluses proliferated more quickly in the dark than under light exposure.(5) The differentiation of adventitious buds from stem calluses was remarkably different at the presence of different hormones.6-BA stimulated the re-differentiation more than KT.The combination of 6-BA 2.0 mg·L^-1+NAA 0.02 mg·L^-1 was the best for the regeneration with up to 50% more adventitious buds and growth of shoots more vigorously than the others.