Abstract
Effects of high temperature and/or controlled transpiration by polyvinyl chloride bagging and/or by spraying with 10% wax, an anti-transpirant, or 500ppm abscisic acid on the occurrence of watercore fruit in Japanese pear 'Hosui' (Pyrus pyrifolia Nakai) were examined. The most severe case of watercore occurred on fruits which were covered with polyvinyl chloride bag from 90 days after full bloom to harvest. Fruits covered with polyvinyl chloride bags containing water from 30 days after full bloom to harvest also succumbed to severe watercore, whereas those sprayed with 10% wax, a transpiration inhibitor, became pithy, had a low specific gravity, and exhibited more watercore than those of the control. Abscisic acid at 500ppm had no significant effect on watercore. Thus, we conclude that the occurrence of watercore correlated closely with high temperature and/or the high rates of transpiration by the fruit.
