2019 ASHS Annual Conference

Rooting characteristics of cuttings in ‘Shine Muscat’ and ‘Kyoho’ grape by twig size, cutting type and time, and temperature were investigated to figure out the optimum cutting conditions. The optimum diameter of twig for rooting was about 11mm in both grape cultivars. The No. of root, root length and rooting rate were higher at node-cut cutting method than at internode-cut cutting method (conventional method) in both grape cultivars. As the cutting time was delayed until 4 April compared to mid-March and end-March, the rooting rate, No. of root, and length of root increased at both grape cultivars. The rate of rooting was higher at the 25^oC cutting bed than at the 30 and 35^oC cutting bed in both grape cultivars. The xylem of ‘Shine Muscat’ twig had about two times amount sucrose and fructose than in those of ‘Kyoho’ twig. However, the rate of rooting was higher in ‘Kyoho’ (about 82%) than in ‘Shine Muscat’ (about 63%) grape cuttings at the same conditions. Therefore, soluble sugar and mineral contents of twig was not related for rooting in our study. To understand the differences in rooting between the ‘Shine Muscat’ and ‘Kyoho’ cultivars, the other factors such as starch and hormones have to be investigated.