Rooting of hardwood cuttings of Shubra white shrub 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 1 cm 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 Bougainvillea peruviana cv. Shubra. Rooting percentage and quality were greatly improved using IBA at 500 ppm. The treatment of 500 ppm IBA achieved the highest rooting percentage (55.6% after 12 hours and 59.4% after 24 hours of treatment), more number of roots per cutting (20.5 and 19.8 at 12 and 24 hours, respectively), higher root length per cutting (46.6 and 49.2 cm), the highest bud break percentage with an increase of 69.5% compared to the control and achieved the highest number of shoots per cutting (2.8), higher number of leaves per cuttings (49 after 12 hours of soaking and 40 after 24 hours of soaking), higher fresh and dry weight of roots per cutting. Also, IBA at 500 ppm treatment showed the highest establishment percentage (68.3 and 53.3% establishment after 12 and 24 hours of treatment time, respectively). At 12 hours soaking time, IBA at 500 ppm and 300 ppm resulted in longer branches (129.2 and 121.3 mm). The treatment of IBA at 500 ppm is recommended for effective hardwood cutting rooting of Shubra white shrub. Time of soaking (12 - 24 h) effect was not consistent and was different among individual treatments.