Efficient rooting of microshoots of tea : a crucial prerequisite for successful hardening and field establishment of micropropagated plants

Abstract

The application of tissue culture techniques for rapid and clonal mass propagation and improvement of tea is well known. While several laboratories have successfully developed in vitro propagation protocols, the use of this technology for mass multiplication of tea at commercial level is still limited largely due to difficulty in the quality of rooting of microshoots, and problems associated with subsequent hardening and field establishment. The present study reports a reproducible protocol for 100% rooting of in vitro propagated tea microshoots using a two-step method. This involves culture of microshoots on IBA (indole-3-butyric acid; 175.0 pM) containing Murashige and Skoog (1962; MS) medium for 10 days followed by transfer to 113 strength MS medium without any plant growth regulator. Besides the concentration of IBA, the period of exposure of microshoots to IBA containing medium (prior to transfer to PGR-free medium) also played a significant role in rooting. In addition, the culture temperature was found to be quite important; for maximum rooting response the optimum temperature range was 25-30°C.