Abstract
We examined the effect of the anther density on callus induction and plant regeneration in floating anther culture and the effect of the removal of the liquid medium adhering to the induced calli before transfer to agar medium on plant regeneration in floating anther culture of rice. Anthers with mid-to late uninucleate pollen grains were collected from a restricted position on the ears on the main culms of the rice plants densely planted in pots. The anthers were cultured by a three-step method consisting of callus induction (liquid medium), callus proliferation (agar medium) and plant regeneration (agar medium) stages. The effect of the anther density was examined using a Japonica rice cultivar, Kita-ake. The rate of callus induction decreased with the increase in the density of anthers in liquid medium from 0.9 to 6 anthers/ml, while further increase in the density up to 12 anthers/ml did not effect any significance. The effect of the removal of the liquid medium adhering to the induced calli before the transfer to agar medium on plant regeneration was examined using two Japonica rice cultivars, Kita-ake and Kirara 397. The wet calli from the liquid medium were blotted with a filter paper for a few seconds before being transplanted onto agar medium. By this procedure, the rate of green-plant regeneration from the calli increased by 13-18%. Thus, we recommend that the density of anthers in the liquid culture be reduced to 3 anthers/ml or less, and that the liquid medium adhering to the calli be blotted with a filter paper for a few seconds before the anthers are transferred to agar medium for plant regeneration.
