Abstract:
Pineapple is one of the most valuable non-traditional export commodities in Ghana. The production of pineapples in Ghana are extensively engaged by resourced poor smallholder farmers. The advent of in vitro propagation of pineapple plantlets is however less exploited. This study was carried to investigate the in vitro response of four pineapple varieties on different media and temperature regimes for their initiation, multiplication and rooting. Meristematic buds from the suckers and slips were excised and initiated on six different media formulations, viz., (MS (0), MS + BAP (1.5 mg L-1 and 3.0 mg L-1), MS + Kinetin (1.5 mg L-1 and 3.0 mg L-1) and IRB505. The Temporary Immersion Bioreactor system (TIBs) together with glass vessels were utilised for culture initiation, multiplication and rooting. A full-strength MS medium supplemented with 3.0 mg L-1 BAP and 20 % coconut water was used for culture multiplication. Plantlets were rooted on MS medium supplemented with three different IAA levels, viz., 0.1 mg L-1, 0.5 mg L-1 and 1.0 mg L-1. Agar was used as a media solidifier and the pH was adjusted to 5.8. Significant differences were observed in the varietal responses to culture initiation, multiplication and rooting for almost all the parameters measured with Smooth Cayenne being the least responsive to in vitro micropropagation. Slips explant significantly (P < 0.05) outperformed suckers explant for culture initiation. Cultures at 25 oC produced the best results over cultures at 19 oC at all micropropagation stages. Cultures in TIBs recorded the highest multiplication rate of 14 per explant for a cycle and produced better roots. However, the Lateral root score decreased with increasing concentration of the IAA. Rooted plantlets potted in a greenhouse and recorded almost 100 % survival rate on acclimatisation.
