Pineapple (Ananas comosus L-Merr) micropropagation in temporary immersion systems

A procedure for the mass propagation of pineapple plants (Ananas comosus L. Merr) using a temporary immersion technique is described. This procedure i nvolved three distinct phases in the automated temporary immersion system: shooting, bud differentiation and elongation. To establish this protocol, w e used in vitro shoots obtained from established liquid culture as starting materials. Three culture methods (solid, liquid and temporary immersion) w ere compared. Temporary immersion increased the multiplication rate and fre sh and dry weight after 42 days. Conventional micropropagation (liquid medi um) and temporary immersion were compared in combination with paclobutrazol . Paclobutrazol promoted the formation of compact bud clusters with limited leaf development. The highest multiplication rate (106) was found when exp lants were cultured in shooting medium (MS+2.1 mg/l BA+0.3 mg/l NAA) supple mented with 1 mg/l PB for 7 weeks. A 10-1 temporary immersion bioreactor wa s used to test two approaches during elongation stage: reduction of the sho ot-formation period or decrease of the initial number of explants. The high est number of competent and uniform plants (191.8 plant/l) was achieved whe n shoots were cultured for 4 weeks in shooting medium supplemented with PB.