A NOVEL TECHNIQUE FOR PRODUCING TWO CROPS PER YEAR OF HIGH-CHILLING ASIAN PEARS IN TAIWAN BY PROVIDING A PROTECTIVE CANOPY

Insufficient chilling in winter and supra-optimum temperature in summer are the main barriers for economic production of temperate-zone pears in Taiwan. In an attempt to solve these problems, the experiments were conducted. The results showed that leaves dropped and bud abnormally opened related to the growth status of shoots. Cytex treatment increased the number of leaves in sequence at node, which delayed the complete defoliation in summer. Cytex treatment also enhanced bud development. The application of BA increased the growth of shoots. A wild pear (Pyrus koehnei, Bean pear) was found to possess the characters of spreading type, low chilling requirement, tolerant to supra-optimum temperature in the summer, and resistance to chilling in the winter. Integration of these and previous results led to the establishment of a novel growing model, i.e., top-grafting Bean pear onto main cultivar Kosui (Pyrus serotina Rehd.) to be a protective canopy. Bean pear canopy serves as a shade in the summer, a strong source under unfavorable environment, and a pollen donors. It also limits the height of plants. As a result, two crops can be harvested separately at early February and July through proper pruning.