Abstract
Effects of the grafting method, cultivars of rootstock and boron application on the causative factors and preventative measures of malformed leaves of grafted cucumber (Cucumis sativus L.) seedlings were investigated. Malformed leaves occurred in insert grafting to the cut rootstock, insert grafting with a rooted rootstock and cleft grafting, but did not occur in approach grafting, even if the hypocotyl of the scion and the rootstock were cut off just after grafting. The occurrence of malformed leaves differed by the rootstock cultivar, and tended to increase using F1 hybrid of Cucurbita maxima Duch × Cucurbita moschata Duch. The occurrence was reduced by foliar application of borax solution at 0.05–0.1% after grafting. The rate of malformed leaves markedly decreased when boron was added to the nutrient solution for 2 days before grafting in hydroponics. The rooting of the rootstock and subsequent growth after grafting were strongly influenced by boron application. The mechanisms of the occurrence of malformed leaves after grafting were discussed.
