Roles of Auxins and Propagation Time in Rooting of Kigelia pinnata Jacq. Cuttings

Cuttings of Kigelia pinnata Jacq. were soaked for 24 hours in solutions of certain growth regulators; IAA, IBA and NAA, each at 250, 500 and 1000 ppm, in addition to untreated cuttings (control), and two propagation times (March and September) taken to define the most suitable combination for the best rooting performance. Naphthalene acetic acid (NAA) at 250 ppm showed the highest rooting percentage (56%) followed by IAA at 250 ppm or IBA at 500 ppm; each recorded 36%, whereas untreated cuttings produced the poorest rooting (11%). Cuttings propagated in March were more successfully and superior to those taken in September to promote rooting percentage and root growth. The best treatment which gave the maximum rooting percentage was more closely associated with stimulated root characteristics. A positive relationship between high rooting ability and high C/N ratio in cutting bases was found. Furthermore, the high rooting capacity was accompanied by a great reduction in phenolic compounds content in cutting tissues. The reduction was apparently associated with NAA at 250 ppm and the propagation in March.