Ripening of European pears: The chilling dilemma

The majority of European pears (Pyrus communis L.) show at some extent resistance to ripening after harvest. Low temperatures and/or ethylene treatments have to be applied to counteract this behavior. This review provides the main protocols that have been used experimentally to ripen European pears grown in the U.S. and summarizes important aspects to understand the ripening physiology of this fruit. Many factors interacting with pear ripening are discussed including, cold storage, controlled atmosphere storage, ethylene treatment, cultivar differences, preharvest temperature, growing region, harvest maturity, storage time and ripening temperature, cooling and warming of fruits, treatments to inhibit ripening, and plant growth regulators.