Production of dodecaploid plants of Japanese persimmon (Diospyros kaki L.) by colchicine treatment of protoplasts.

Dodecaploid plants of Japanese persimmon (Diospyros kaki L.) were obtained by colchicine treatment of protoplasts. Callus protoplasts of 'Jiro' (2n=90, x=15) were cultured in modified KM8p medium with 0.1% colchicine for 3-9 days. After colchicine treatment, they were cultured using agarose bead culture. Microcalli were recovered from the protoplasts after 3 months. Flow cytometric measurement showed that nine of 31 callus lines obtained from 6 days of colchicine treatment had twice the nuclear DNA content as non-treated controls. Plantlets were regenerated from the calli with twice the nuclear DNA content. Microscopic observation of root tip cells showed that their somatic chromosome number was 2n=180 (x=15). Compared with 'Jiro', dodecaploid plants had longer stomatal guard cells and lower stomatal densities, consistent with increased ploidy.