INDUSTRY AND RESEARCH ON PERSIMMON IN JAPAN

The total growing area for persimmon (Diospyros kaki) in Japan is estimated at 25,700 hectares in 2001. The ratio of production in 2001 over 1985 was approximately 1.0 for persimmons, compared with 0.6 for citrus and about 1.5 for Japanese apricot. Currently, the principal cultivars are ‘Fuyu,’ ‘Matsumotowase- Fuyu,’ ‘Nishimurawase,’ ‘Jiro,’ and ‘Wasekei Jiro’ for non-astringent types. Astringent types include ‘Hiratanenashi,’ ‘Tonewase,’ ‘Hachiya,’ ‘Ichidagaki,’ and ‘Saijo.’ ‘Fuyu’ has always been the most popular non-astringent cultivar. Cultivation area for ‘Fuyu’ accounted for 17% of the total persimmon in 1934, peaked at 38% by 1986, and then gradually decreased to 27.4% by 2001. ‘Hiratanenashi’ and ‘Tonewase’ are the dominant astringent type cultivars; the area for ‘Hiratanenashi’ cultivation rapidly increased by 1974 and then remained at about 15% since. Although ‘Tonewase’ has been cultivated only since 1986, its popularity has grown dramatically, with its cultivation area reaching to 13% in 2001. The National Institute of Fruit Tree Science in Japan has introduced new, early-ripening cultivars such as ‘Taishuu.’ Recently, a horizontal trellis training system has been developed to alleviate the hard labor involved with the conventional training system. This report also focuses on the mechanism of fruit softening, removal of astringency, the techniques for prolonging shelf-life of fruits, and a selection system for non-astringent cultivars.