S16 - Session P1 - Application of top-grafting pear cultivation in the tropical area of Taiwan

Authors: YungChou Lin *

The top-grafting technique of Asian pear ( Pyrus pyrifolia ) is unique and usually applies in the subtropical area of Taiwan to overcome the insufficient chilling accumulation. However, while climate change impacts agriculture production in Taiwan, the effectiveness of this technique is uncertain. To evaluate whether this operation is feasible in warmer regions, we did the top-grafted experiment in Hengchun (the southernmost and lowland tropical area of Taiwan) in February 2021. The flower bud of five pear varieties ('Ruh Yue', 'Shinko', ' Hosui', 'Tainung no.2', and 'Akizuki' ) were top-grafted onto 'Laio Li', that is a low chilling requirement local variety. After two weeks of grafting, the budburst rate of 'Ruh Yue' and 'Akizuki' were more than 60%, higher than other varieties. After four weeks of grafting, 'Ruh Yue' and 'Hosui' have the best budburst rate (85% and 86%, respectively). The grafting survival rate of 'Ruh Yue' and 'Hosui' were more than 82%, but 'Shinko', 'Akizuki', and 'Tainung no.2' were less than 71%. The harvest time of Asian pears in Hengchun were earlier than in the subtropical area of Taiwan, but the fruit weight were lighter. Besides, due to the high temperature environment in Hengchun, 'Tainung no.2' and 'Hosui' usually have water core symptom after low temperature(4℃) storage. Among all varieties, 'Ruh Yue' had the best yield due to the high grafting survival rate and fruit numbers in Hengchun. To summarize, 'Ruh Yue' might be a potential cultivar in the tropical area of Taiwan.