ABSTRACT
The grafting in Araucaria angustifolia is an alternative choice related to the production of seedlings using seeds. However, the natural availability of propagules is very limited, since only material obtained from the trunk (orthotropic) could be used. The aim of this study was to evaluate the grafting technique on branches of Araucaria and the graft tropism in order to have the propagule multiplication. The grafting was held in the beginning of July 2014 using the patch grafting technique in 20 plants of 3-year old Araucaria angustifolia. It was used orthotropic buds obtained from trunks and grafted in 43 branches located in the last three upper whorls, within a distance of 10 cm from the rootstock plant trunk. It was evaluated the graft survivals, the healing quality, the tropism (growth angle), the height and diameter of the graft shoots, as well as the diameter of rootstock branches and its relation to the diameter of the graft. Data were analyzed by descriptive statistical tools. The grafting in Araucaria branches is viable. Despite the morphological and functional differences, the interaction among grafts with orthotropic origin and plagiotropic rootstock branches does not interfere in the setting, healing and the initial growth of the grafts, at least up to 180 days after grafting. Therefore, the possibility of grafting in several branches of a same plant configures an alternative option for the multiplication of orthotropic propagules. The tropism of shoots depends on the graft origin. Trunciform propagules (obtained from the trunk) are not affected by the interaction when grafted on plagiotropic rootstock branches, showing shoots with orthotropic growth and youth trunk morphology. The upper whorl branches are the most suitable for grafting, aiming the multiplication of orthotropic propagules, because they are less subject to the apical dominance.
Keywords:
tropism; plagiotropic; orthotropic; vegetative propagation
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