TWO ASTRINGENT PERSIMMON CULTIVARS RELEASED BY NARO INSTITUTE OF FRUIT TREE SCIENCE, JAPAN

The national institute in Japan has conducted persimmon breeding since 1938, emphasizing the improvement of pollination constant non-astringent (PCNA) cultivars. However, PCNA cultivars of Japanese origin is a recessive trait, and its genetic resources are very limited, and repeated crossings within the narrow gene pool led to inbreeding, which hinders tree vigor, productivity, and fruit weight. Therefore, a strategy of obtaining PCNA offspring through the backcross (PCNA×non-PCNA)×PCNA has been going on since 1990. Two astringent selections from the first phase were released as new pollination variant astringent (PVA) cultivars ‘Taiten’ and ‘Taigetsu’ in 2007, both of which are derived from the cross of ‘Kurokuma’ (a local PVNA cultivar in Japan) × PCNA cultivar ‘Taishu’. Trees of both new cultivars are vigorous and productive. Crosses between each of those new cultivars and PCNA genotype yielded around one fifth PCNA offspring of the total. The ‘Taiten’ fruit ripens in late November, comparable to ‘Fuyu’ at the national institute in Akitsu. Its fruit weighs an average of 506 g. The flesh is soft, moderately coarse and very juicy. The soluble solids concentration in juice after removing astringency (SSC) averages 16.5%, which is comparable to ‘Fuyu’. Fruit cracking at the calyx or stylar end is rare. However, small areas of shallow concentric cracks on fruit skin (SCCS) occur in a considerable ratio of the fruit. The ‘Taigetsu’ fruit ripens in early November at Akitsu. Its fruit weighs an average of 459 g. The flesh is soft, moderately coarse and very juicy. The SSC averages 15.4%, which is comparable to ‘Hiratanenashi’. Fruit cracking at the calyx or stylar end is rare. SCCS are likely to occur in a considerable ratio of the fruit. Parthenocarpy in ‘Taigetsu’ is high.