EFFECT OF MS MEDIUM STRENGTH AND GROWTH REGULATORS (TDZ & KIN) ON Dendrobium nobile ORCHID In vitro REGENERATION

Dendrobium nobile Lind. orchid plants occupy an important role in floriculture trade, as cut flowers, flowering pots and garden plants due to their beautiful attractive flowers with extensive variations in color shoot proliferation. Trials were carried out for comparing the effects of TDZ and KIN, on Dendrobium in vitro regeneration. In order to achieve the best growth, in vitro-derived plantlets were cultured on full, 3/4 and 1/2 MS salts strengths supplemented with Thidiazuron (TDZ) at 0.0, 1.0, 2.0 and 3.0 mg/l and Kinetin (KIN) at 0.0, 1.0 and 2.0 mg/l in combinations. Healthy individual shoots were cultured on 1/2 MS salts supplemented individually with indole-3-butyric acid (IBA) and 1-naphthalene acetic acid (NAA), at 0, 1, 3 and 10 mg/l to study their effects on root formation. Results in this study, show that full MS was the best strength among MS strengths, gave the best regeneration efficiency, achieving highest values of shoot number, fresh weight and growth value. In addition, different regeneration responses were noticed by using TDZ alone or combined with KIN, the best regeneration efficiency was obtained in a medium supplemented with a combination of KIN and TDZ both at 1.0 mg/l as, it enhanced significantly shoot number and leaf number after 3 subcultures. Furthermore, IBA exceeded NAA in formation of roots (number and length) and shoot fresh weight. Moreover, the plantlets were hardened well in peat moss substrate and achieved 91% of survival rate.