2015) The use of mini-tunnels and the effects of seasonality in the clonal propagation of Eucalyptus in a subtropical environment, Australian Forestry, 78:2, 65-72,
SummaryEnvironmental seasonality plays a key role in the physiological processes of root formation in vegetative reproduction for commercial cloning. The authors hypothesised that (1) subtropical climatic seasonality causes higher rates of Eucalyptus minicutting production and rooting during warmer months and (2) the use of mini-tunnels to cover the stumps (stools) providing cuttings would enhance these processes year round. This study evaluated the effects of seasonality and the use of mini-tunnels using eight clones of Eucalyptus spp. under subtropical environmental conditions over the course of a year. The production systems studied were (1) mini-stumps planted in a clonal hedge (control) under a retractable roof shelter and (2) mini-stumps planted inside mini-tunnels under the same shelter. Five parameters were evaluated: (1) the temperature in the two environments; (2) the production of mini-cuttings by the stumps; (3) foliar area of the cuttings at harvest; (4) the survival of cuttings after 30 days in the greenhouse with micro-sprinklers and (5) rooting of cuttings at 45 days from setting. The use of minitunnels increased air temperature, increased mini-cutting production by 53% and promoted a reduction in foliar area of the cuttings at harvest. Rooting was found to be greater in warmer months (summer and spring) with an overall mean rooting rate of 80% versus 68% during the colder months (autumn and winter). The hypothesis that mini-tunnels enhance rooting of the cuttings produced in them was only partially confirmed, as this technique improved rooting (from 76% to 85% for the control versus the mini-tunnel conditions, respectively) only during the warmer months.