Study on the flowering and fruiting phenological law of 'Sijihua' longan (Dimocarpus longan) and its regulation.

According to the phenological characters of 'Sijihua' longan (Dimocarpus longan Lour.), the effects of several plant growth regulators on the flower formation and the fruit setting were investigated through the multi-factors orthogonal experiment design in this study. The results showed that there were no significant differences among the abilities of flower formation and fruit setting of branches matured in different periods, and the reasonable combined treatment of ethephon, paclobutrazol and gibberellin could promote the flower formation and fruit setting of 'Sijihua' longan. The treatment of crown sprayed with the ethephon and the paclobutrazol at 200 mg.L -1 and 350 mg.L -1 , respectively, when the shoots were matured, could effectively inhibit the shoot germination and increase the rates of flower formation to 100%, as well as enable the inflorescence sprouting and fruiting well. Being sprayed again by the GA 3 of 40 mg.L -1 after the inflorescence was germinating; the fruit clusters could display the best comprehensive characters.