Abstract
A chill unit model for ‘Nijisseiki’ pear was developed for prediction of leaf bud rest completion under Koyama and Saji conditions. The model assigns full effect for chilling accumulation for temperatures below 8°C until its value reaches 1200, and then it cuts the lower temperature below -4.0°C off for chilling accumulation. The model is more suitable in predicting rest completion of ‘Nijisseiki’ pear than previously reported models. By using the model, it is suggested that chilling requirement of leaf bud of ‘Nijisseiki’ pear should be 1400 chill unit.
