PRODUTIVIDADE DE MINICEPAS E ENRAIZAMENTO DE MINIESTACAS DE HíBRIDOS DE Eucalyptus globulus LABILL. EM RESPOSTA A NITROGêNIO

摘要

The aim of this study was to evaluate the productivity of ministumps and the rooting of minicuttings from hybrid clones of Eucalyptus globulus in response to nitrogen concentrations in nutritive solution, in a fertirrigation system. To do so, we used five clones, namely: two of Eucalyptus urophylla x Eucalyptus globulus (C-04 and C-16); two of Eucalyptus grandis x Eucalyptus globulus (C-26 and C-30) and one of Eucalyptus urophylla x Eucalyptus grandis (1213) as a comparator. Five N concentrations were tested (36, 72, 109, 164 and 218 mg L -1 ) in a statistical design of randomized blocks on a split plot arrangement with three replications. Six months after the implementation, using standard nutritive solution, in fertirrigation system, the treatment application began. After 30 days, it began the weekly harvest of minicuttings and the cutting plantion at every 15 days, during 90 days. It was evaluated the survival and the productivity of the ministumps and, regarding the minicuttings, it was observed: the survival, the rooting percentage, the minicutting percentage with visible roots at the lower end of the tube, having these 10cm, after 30 days in the greenhouse. It was found that there is a significant effect of N concentration over the monthly productivity of ministumps from clones C-16 (169.05 mg L -1 ), C-26 (146.67 mg L -1 ) and for C-04 and 1213, (positive linear effect). However, no significant effect of dose was observed for the percentage of visible roots at the lower end of the tube, rooting and survival of cuttings at thirty days in the greenhouse.