Rooting of firebush shrub hardwood cuttings using growth regulator long duration application

Vegetative propagation through stem cuttings is the most vital method to reproduce plants and conserve their innate desirable characters. Sixty uniform hardwood cuttings with the same number of nodes of one-centimetre diameter were used to test the influence of indole-3-butyric acid (IBA) and naphthalene acetic acid (NAA) after 12 and 24 hours of soaking on induction, growth of adventitious roots and establishment of firebush (Hamelia patens Jacquin) hardwood cuttings was examined. Cuttings vitality expressed as bud break responded positively to growth regulators treatments. The treatment of IBA at 500 ppm achieved the highest bud break percentage with an increase of 70.5% compared to the control. Also, IBA at 500 ppm achieved the highest rooting percentage (65.6% after 12 hours and 69.4% after 24 hours of treatment), greater number of roots per cutting (30.5 and 29.8 at 12 and 24 hours, respectively), longer roots per cutting (36.6 and 9.2 mm), higher fresh and dry weight of roots per cutting, the highest number of branches per cutting (8.8) and greater number of leaves per cutting (65.3 and 48.3% after 12 and 24 hours of treatment duration, respectively). The treatment of IBA at 500 ppm achieved the highest establishment percentage (68.3 and 53.3% establishment after 12 and 24 hours of treatment time, respectively). At twelve-hour soaking time, IBA at 500 ppm and 300 ppm resulted in longer branches (159.2 and 151.3 mm). The treatment of IBA at 500 ppm is recommended for effective hardwood cutting rooting of firebush. Time of soaking (12-24 h) effect was not consistent and was different among individual treatments.