Abstract
Many persimmon (Diospyros kaki thunb.) cultivars are hexaploid (2n = 6x = 90), which bear seeded fruits. In contrast, seedless persimmon cultivars are nonaploid (2n = 9x = 135) such as ‘Hiratanenashi’, which bear astringent fruits only. We developed nonaploid pollination constant non-astringent (PCNA) persimmon cv. ‘Fukuoka K1 Gou’ (TM; Akiou) by embryo culture of imperfect seeds derived from a cross between ‘Fuyu’ and ‘Taishuu’, both of which are hexaploid PCNA cultivars. ‘Fukuoka K1 Gou’ fruit ripens in mid-October to early November, being almost the same as ‘Taishuu’. The soluble solid content of fruit was 19.6 °Brix that was higher than in ‘Fuyu’ and ‘Taishuu’. The fruit weight was 365 g, being heavier than that of ‘Fuyu’ and almost the same as that of ‘Taishuu’. The fruit skin of ‘Fukuoka K1 Gou’ at harvest time was less reddish than that of ‘Fuyu’. Parthenocarpy and stenospermocarpy abilities of ‘Fukuoka K1 Gou’ were low, causing unstable fruit set, especially in young trees. Spraying 200 ppm of the gibberellin on fruit at 10 days after full bloom and flower thinning before anthesis were both effective for improving the fruit set. Moreover, the combination of both treatments improved the fruit set significantly more than individual treatment.
