A NOVEL METHOD FOR RAPID MICROPROPAGATION OF PINEAPPLE

A novel micropropagation method for pineapple (Ananas comosus L.), bas ed on shoot elongation induced in vitro, was demonstrated for two cult ivars. Decapitated in vitro plantlets were used as explants. Shoot eti olation was induced by placing explants in a Murashige and Skoog (MS) medium containing NAA (10 mu M) and incubating in darkness at 28C for3 0 to 40 days. The mean number of the regenerated etiolated shoots per explant was 2.6+/-0.29. The etiolated shoots were placed into N6 mediu m supplemented with kinetin or BA (25 or 20 mu M, respectively). After 4 to 6 weeks, shoots regenerated along the nodes. The highest regener ation rate was 15 and 13 plantlets per node with 25 mu M kinetin and 2 0 mu M BA, respectively. Regenerated plantlets were rooted on a growth -regulator-free MS medium. Residual shoots of the initial explants cou ld be recycled by rooting on a growth-regulator-free MS medium. This p rocedure enables the regeneration of several thousand plantlets per ye ar. Chemical names used: naphthaleneacetic acid (NAA); benzyladenine ( BA).