Cultivation of lower-chilling peach cultivar 'KU-PP1' in plastic house without heating

The plant growth and fruit quality of lower-chilling peach 'KU-PP1' (500 CH), grown in an unheated plastic house from 250 to 900 CH, were investigated. When the trees planted in the ground were forced from 250 CH just after hydrogen cyanamide application, bud burst, flowering and harvest occurred a month or more earlier than the trees grown under field conditions. Despite the very early flowering under unheated conditions, frost injury was not observed in the forcing cultures. Fruits of the forced trees were harvested as early as early-May. When the trees planted in containers were forced from 250, 500 and 900 CH, bud burst was accelerated with hastening the onset of forcing. However, the forcing time hardly affected the flowering and harvest time. The fruit quality under forcing from 250 and 500 CH was superior to that from 900 CH. These results demonstrated that the cultivation of lower-chilling peach 'KU-PP1' in an unheated plastic house from early season enabled a very early harvest without frost injury in this region.