Postharvest fruit softening in forcing-cultured 'Tonewase' Japanese persimmon (Diospyros kaki Thunb.)

Postharvest fruit softening after removal of astringency was studied in for cing-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 harve st and the control fruit. 2. The rate of fruit softening after removal of astringency varied with eac h greenhouse. The structure and respiration rate in the root system, minera l composition, and water potential in leaf had no relationship with the rat e of postharvest fruit softening. 3. Irrespective of forcing-cultured or open field, the days of treatment, a nd early harvest resulted in rapid fruit softening after removal of astring ency by CTSD method. Harvesting later than 120 days after anthesis when fru it 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 acce lerated postharvest fruit softening after removal of astringency by CTSD me thod. In conclusion, postharvest fruit softening is closely dependent on fruit ma turity at harvest. Exposure to high temperature during the maturation stage affects maturity indices and physiological activity in fruit, resulting in rapid fruit softening.