DEVELOPMENT OF PRE-ACCLIMATIZED BANANA PLANTLETS OBTAINED FROM TISSUE CULTURE

The objective of this study was to evaluate the development of pre-acclimatized banana plantlets cv. Pioneira (Musa sp., group AAAB) obtained from tissue culture. Seedlings were multiplied in five subcultures (30 days each), on MS medium supplemented with 5 mg.L^-1 BA (benzylaminopurine), solidified with agar gel, pH 5.8, under 20 hours photoperiod, 2,000 lux of light intensity and temperature of 25±2°C. The in vitro rooting was performed on MS medium. Plantlets were pre-acclimatized for 30 days in a greenhouse, under controlled conditions of temperature and irrigation. These plantlets, 4.8±1.5 cm high, were then transferred to plastic bags containing organic substrate. Growth and development of the plantlets were evaluated under several conditions: greenhouse, humid chamber in greenhouse, screenhouse, humid chamber in screenhouse, under tree canopy, humid chamber under tree canopy and in-field conditions. A completely randomized design was used with five replications, each replicate containing 10 plantlets. Evaluations of plantlet development were performed at 60 and 120 days after transplanting. All treatments showed 100% plantlet growth, except for the direct field transplanting (39.7%). The plantlet development was similar in greenhouse, screenhouse, and under tree canopy conditions. The proposed system shows feasibility for use in long-distance distribution of micropropagated plantlets.