Chilling Injury in Eggplant Fruits

It has been known that eggplant fruits show the typical symptoms of chilling injury when they are stored at low but non-freezing temperature. Using this material authors have been studying the mechanism of chilling injury, and the present paper reports a general aspect of the occurrence of injury and a microscopic observation of the pitting development. Cultivar ‘Senryo’ was mainly used and stored at 1°, 6°, 10° and 20°C in perforated polyethylene bags.The fruits harvested in July showed a severe pitting at 1° and 6°C, and transferring of low temperature-stored fruits to 20°C hastened the development of the injury. At 10° and 20°C of storage temperature no pitting was found. When low temperature-stored fruits were transferred to 20°C rapid decay developed starting mostly with calyx part. The incidence of the decay was faster in the fruits stored at low temperature for longer period, while the storage within 3 days at 1°C did not show effect. Even 10°C of storage temperature showed a negative effect when the fruits had been kept for 5 days or more, and the fruits transferred to 20°C decayed more rapidly than that stored at steady 20°C.In the fruits harvested in October, no pitting was found during the storage at 6°C and after transferring from 6°C to 20°C. The calyx decay, too, delayed as compared with the fruits harvested in July. Some other observations, using cultivars other than Senryo, also suggested that the fruits harvested in cool season are less sensitive to low storage temperature.Considering the incidence of decay at the elevated temperature, storage temperature above 10°C is recommended for the fruits harvested in warm season, while 10°C or below may be preferable for the cool season fruits.Under the microscope it was found that the pitting injury commenced with deformation and browning of the cells which locate several layers inside surface, and the water loss from the surface had no relation to the pitting at the first stage of the injury development.