A novel micropropagation method for pineapple (Ananas comosus
L.), based on shoot elongation induced in vitro, was
demonstrated for two cultivars. Decapitated in vitro plantlets
were used as explants. Shoot etiolation was induced by placing
explants in a Murashige and Skoog (MS) medium containing NAA (10
mu M) and incubating in darkness at 28C for30 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 medium
supplemented with kinetin or BA (25 or 20 mu M, respectively).
After 4 to 6 weeks, shoots regenerated along the nodes. The
highest regeneration rate was 15 and 13 plantlets per node with
25 mu M kinetin and 20 mu M BA, respectively. Regenerated
plantlets were rooted on a growth-regulator-free MS medium.
Residual shoots of the initial explants could be recycled by
rooting on a growth-regulator-free MS medium. This procedure
enables the regeneration of several thousand plantlets per year.
Chemical names used: naphthaleneacetic acid (NAA); benzyladenine