Protuberance-mediated high frequency of adventitious shoot regeneration from sweetpotato leaf explants [ Ipomoea batatas (L.) Lam.

Abstract

In this report, a novel, reproducible and efficient protocol for protuberance-mediated adventitious shoot regeneration has been established for sweetpotato [Ipomoea batatas (L.) Lam.]. The leaf explants were cultured on a modified Murashige and Skoog (MS) medium containing various concentrations (0.5, 1.0, 2.0, 5.0 or 10 μM) of Thidiazuron (TDZ). The adventitious shoots were developed from the base of leaf explants on an MS medium supplemented with 2.0, 5.0 or 10.0 μM TDZ. The responsive explants were transferred to a freshly modified MS medium containing TDZ. Green-colored, oval, or cone-shaped shoot-forming protuberances were developed from explants. It appeared that the frequency of protuberance development depended on the concentration of TDZ. However, this did not further improve, when the concentration of TDZ increased from 5.0 μM to 10.0 μM. Adventitious shoot buds were developed from protuberances, and the histology of protuberances revealed a direct origin of shoot buds. In vitro raised shoots were rooted either on a modified MS medium alone or on a modified MS medium containing indole-3-butyric acid (IBA). The regenerated plants were acclimatized and successfully established in a greenhouse.