Propagation of some woody Australian plants from cuttings

Abstract

For successful propagation of some woody Australian plants by cuttings it was beneficial to dip the lower 2 cm of the stem in an ethanolic solution of indole-3-butyric acid (IBA). For Chamelaucium uncinatum (Geraldton wax), 90% of cuttings rooted following treatment with the optimal IBA dose of 4000 mg/L for 40 s, while non-treated cuttings rooted poorly or not at all. After 21 days each rooted cutting had formed 4.2 ¦ 0.4 roots, with each root having an average length 42.5 ¦ 3.2 mm. Powder formulations of 3 g IBA/kg talc (0% rooting after 21 days) or a commercial preparation containing 0.05 g ß-naphthaleneacetic acid (NAA) and 0.02 g indole-3- acetic acid (IAA)/kg (30% rooting after 60 days) were less effective. When rooting was rapid, with extensive root formation within 3 weeks, >90% of cuttings survived transplanting. Rapid rooting required the bottom heat of the propagator to be run at 25-30¦C when air temperature was maintained at 20¦C. Rooting was good (85%) for cuttings taken from parent plants grown at 24/19¦C (day/night) and 18/13¦C but was less (43%) for cuttings taken from plants grown at 30/25¦C. Propagation is usually less successful where the stem is woody rather than young and fleshy; parent plant condition, therefore, will have some effect on propagation success. Sixteen other woody Australian species examined also rooted well when propagated with a quick dip in a solvent-IBA mix and had a similar positive response to root-zone warming.