Auxin, wounding, and propagation medium affect rooting response of stem cuttings of Arbutus andrachne

Stem cuttings of Arbutus andrachne L. were taken from basal or terminal portions of branches in October and treated with acid or salt forms of IBA or NAA at several concentrations. Also, the effects of wounding and propagation medium were assessed. Auxin was necessary for root formation, IBA acid being most effective. In general, salt forms of IBA and NAA were less effective than acid forms. Concentration of auxin had a significant effect on rooting regardless of auxin type or chemical form. The greatest rooting percentage, root number, length, and fresh and dry weights were exhibited by basal cuttings treated with 24 mm IBA. Position of the cutting on the branch did not affect rooting except when the IBA acid form was used; basal cuttings were then superior to terminal ones. Wounding, by making two opposite longitudinal incisions at the base of the cutting, increased rooting. The propagation medium had a significant effect on adventitious root formation, which was enhanced with increasing perlite percentage in the medium up to 100%. Chemical names used: 1H-indole-3-butyric acid (IBA); alpha -naphthaleneacetic acid (NAA).