カキ‘刀根早生’促成栽培果実の収穫後の軟化発生

Abstract

Postharvest fruit softening after removal of astringency was studied in forcing-cultured Japanese persimmon 'Tonewase' (Diospyros kaki Thunb.). 1. No significant difference in the fruit softening rate was observed among the fruits in which astringency was removed by on-tree ethanol application or by the constant temperature of short duration (CTSD) method after harvest and the control fruit. 2. The rate of fruit softening after removal of astringency varied with each greenhouse. The structure and respiration rate in the root system, mineral composition, and water potential in leaf had no relationship with the rate of postharvest fruit softening. 3. Irrespective of forcing-cultured or open field, the days of treatment, and early harvest resulted in rapid fruit softening after removal of astringency by CTSD method. Harvesting later than 120 days after anthesis when fruit growth phase shift from phase II to phase III delayed the fruit ripening rate. 4. High temperature treatment during fruit growth from July to October accelerated postharvest fruit softening after removal of astringency by CTSD method. In conclusion, postharvest fruit softening is closely dependent on fruit maturity at harvest. Exposure to high temperature during the maturation stage affects maturity indices and physiological activity in fruit, resulting in rapid fruit softening.