CLONING FIELD GROWING EUCALYPTUS UROPHYLLA x EUCALYPTUS GRANDIS BY ROOTED CUTTINGS: AGE, WITHIN-SHOOT POSITION AND SEASON EFFECTS

Eucalyptus is a vast genus encompassing species used as ornamentals, for landscaping but also for wood production. The possibility to clone field selected individuals by rooted cuttings was assessed on Eucalyptus urophylla x Eucalyptus grandis, studying the influences of donor plant age, within-shoot position and season on adventitious rooting ability of the cuttings. The plant material consisted of (i) 8 year-old mature rooted cuttings derived from a 24 year-old E. urophylla x E. grandis genotype and (ii) 3 month-old juvenile seedlings issued from the same parents as the mature genotype. Crown-collected terminal cuttings rooted better when coming from juvenile than from mature individuals particularly during the dry season but not during the rainy season. Nodal cuttings collected from sprouting stumps of the same Juvenile and mature sources after felling of the original ortets displayed similar survival and rooting rates, notwithstanding noticeable variations according to the seasons and to the initial position of the cuttings within the shoot from which they originated. Overall, juvenile nodal cuttings produced more adventitious roots than mature ones, but this criterion had no significant practical impact on further survival and growth of the rooted cuttings at the planting time and later.