Characteristics for the clonal propagation of Eucalyptus globulus Labill.

摘要

The genus Eucalyptus comprises important tree species that are planted mainly for ornamental and landscaping purposes, in addition to timber and pulpwood production. While the cuttings of some species of this genus have higher rooting ability, Eucalyptus globulus have lower rooting ability, which makes clonal propagation difficult. In this study, we assessed the effects of internode position within shoots on the preparation, seasonal timing, and type and concentration of auxins on the rooting of cuttings. We recorded higher rooting efficiency around the seventh internode. Rooting efficiency varied across the year and was roughly correlated with the temperature of the rooting substrate. Although the efficiency in winter (approx 30%) was lower than that in summer (approx. 60%), it was improved to the same level by the bottom heat treatment of the rooting substrate. Among the tested auxins, a concentration of 0.8% IBA produced the best rooting score. The rooting efficiency with 0.8% IBA was over five times higher than that of the control without any auxins. Compared to the application of IBA alone, the combined application of 0.8% IBA and 0.5% of a diphenylurea derivative, N,N'-bis-(3,4-methylenedioxyphenyl)urea, to the cuttings increased by 34% and 57% both rooting and survival efficiencies, respectively.