TDZ induces shoot regeneration in various Kalanchoe blossfeldiana Poelln. cultivars in the absence of auxin

In order to optimize shoot regeneration in Kalanchoe blossfeldiana, leaf and internode explants of seven cultivars including one inter-specific were studied. The effects of various combinations of a-naphthalene acetic acid (NAA) (0, 0.57 M) and thidiazuron (TDZ) (0, 0.45, 4.5, 22.5, 67.5 mu M) on MS medium were examined. In all cultivars shoot regeneration frequency and number of shoots per explant were enhanced by increasing TDZ concentration. Supplementing the media with NAA did not improve shoot regeneration. Maximum regeneration frequency and optimum concentration of TDZ for shoot regeneration depended significantly on the cultivar. Internode explants, but not leaf explants, of some cultivars, were able to produce adventitious shoots without treatment with growth regulator.