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We obtained nonaploid plants by embryo culture of imperfect seeds derived from a cross between 'Fuyu' and 'Taishuu', both of which are commercially important persimmon cultivars. Furthermore, we aimed to clarify the origin of nonaploid plants derived from imperfect seeds. Of 1078 seeds, 68 were imperfect; this accounted for 6.3% of the total number. Ten of the 68 seeds germinated into seedlings, and two produced abnormal plantlets without meristems at both the shoot apex and root tip. The remaining eight produced normal-appearing plantlets with normal growth. Two seedlings were recovered from the abnormal plantlets via callus, and grew vigorously in the greenhouse. Cytogenetic analysis confirmed that these two seedlings were nonaploids. Parental analysis using four simple sequence repeats (SSR) markers, D.CT-13, 24, 61 and 179, showed that each nonaploid seedling had alleles originating from the parents, indicating that they were generated by syngamy. The two nonaploid seedlings had alleles of 222 bp at D.CT-61, which is peculiar to the pollen parent, 'Taishuu', whereas they did not have an allele of 136 or 140 bp at D.CT-179, which is peculiar to the seed parent, 'Fuyu'. These results suggest that they might be derived from fertilization of a reduced female gamete with an unreduced male gamete.

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Chromosome doubling with colchicine treatment of seedlings derived from cross among hexaploid persimmons (Diospyros kaki Thunb.) were carried out to induce dodecaploid persimmons. Colchicine treatment of the meristem of seedlings in vitro was effective at a concentration of 0.03-0.05% for 12-24 hours. Induced dodecaploid seedlings generally showed weak vigor, but some vigorous seedlings could be obtained. Compared with the hexaploid parent cultivar, these dodecaploid seedlings had longer stomatal guard cells and lower stomatal densities. Although the rate of flower bud on dodecaploid seedlings was lower than that of the hexaploid seedling, some of the seedlings bore both pistillate and staminate flowers. Since the pollen of the induced dodecaploid seedlings has germination ability, the seedlings could be parental stocks for the breeding of seedless-PCNA persimmons.