Induction of pollen plantlets in rice by spikelet culture.

Induction of pollen callus and subsequent regeneration of plantlets from the callus have been achieved from rice spikelets cultured in a liquid medium containing sucrose, α-naphthalene-acetic acid and kinetin. When spikelets are cultured in a medium containing 6% sucrose, calluses are released into the medium where they continue to increase in size without undergoing organogenesis. On the other hand, in a medium containing 2% sucrose, calluses are retained within the anther locule where they differentiate into plantlets. Cytological studies have shown that calluses have their origin either in the vegetative cell of asymmetrically dividing pollen grains or in both cells of pollen grains which divide more or less equally.