Influence of Prolonged Exposure to Chilling Temperatures on Bud Break and Heat Requirement for Bloom of Several Fruit Species

Abstract

Abstract Shoots of apple (Malus domestica Borkh.), cherry (Prunus avium L.), peach [Prunus persica (L.) Batsch] and pear [Pyrus communis × Pyrus pyrifolia (Burm.) Nakai] were collected and used in these studies. In all instances, chilling beyond that required for 50% bud break within a 2-week period (prolonged chilling) resulted in a decrease in the growing degree hours required for bud break. In many cases, over 90% of the variation in each study could be attributed to the added chilling.