Leaf discs (0.46cm² were collected from adventitious shoots of 'Matua' Kiwi cultivated in vitro and were conditioned during 24 hours in liquid medium with 2.4- D (5mg/l). After this period they were cultured in MS medium additioned with Thidiazuron in the concentrations following: 0; 0.25; 0.5; 1; 2; 4; 8 and 16mg/l. Explants were inoculated with the adaxial surface in contact with the culture medium and were maintained for about three weeks at 25°C in darkness. After this time they were kept for three weeks in a growth room and exposed to a 16 hour photoperiod, light intensity of approximately 2,000 lux and temperature of 23 ± 2°C. The higher concentrations of Thidiazuron (8 and 16mg/l) were phytotoxic, leading to explant death. Rooting was observed only in the control treatment. Callus intensity formation, adventitious shoots number, callus dry matter weight and bud number showed a quadratic response to the Thidiazuron concentrations. Concentrations of Thidimuron were not efficient to increase the adventitious shoot number of Kiwi. Callus intensity increased until 2.21 mg/l Thidiazuron concentrations, and declined afterwards.
Actinidia deliciosa; tissue culture; Thidiazuron; TDZ
