INFLUENCE OF ROOTING MEDIA AND INDOLE-3-BUTYRIC ACID (IBA) CONCENTRATION ON ROOTING AND GROWTH OF DIFFERENT TYPES OF CONOCARPUS ERECTUS L. STEM CUTTINGS

The present study was conducted to evaluate the influence of rooting media (clay, peat moss + sand, peat moss + perlite and vermiculite), cutting types (tip, middle and basal) and different concentrations of indole-3-butyric acid (control, 50, 100 and 200 ppm IBA) on the rooting and growth of Conocarpus erectus L. stem cuttings. The experiment was laid out in a split-split-plot design, with three replicates. The obtained results showed that vermiculite was the best rooting medium used for improving the rooting percentage, root number, root length, stem length, branch number and leaf number per rooted cutting, followed by peat + perlite (1:1 in v/v) and peat + sand (1:1 in v/v), respectively comparing with clay soil which recorded the lowest values. The tip cutting was superior to the middle and basal ones in all rooting media used, especially in vermiculite medium. Among IBA concentrations used, cuttings treated with IBA at 100 ppm produced significantly better rooting (42.9%) than 50 ppm (36.3%), 200 ppm (36.0%) and untreated cuttings (23.1%). The greatest rooting percentage (95.0%) and the best root and growth characteristics as well as the highest endogenous contents of phenols, indole acetic acid (IAA) and the lowest abscisic acid (ABA) contents were obtained from tip cuttings treated with IBA at 100 ppm and planted in vermiculite substrate. Moreover, the combined treatment of 100 ppm IBA and vermiculite substrate significantly improved the rooting percentage, root and growth measurements of middle and basal cuttings as well as gave the highest C/N ratio in basal cutting tissues compared to the same cutting types combined with the other rooting media and IBA concentrations. Hence, it could be recommended to treat the different types of C. erectus stem cuttings with IBA at 100 ppm and planting in vermiculite medium for improving rooting, quality and growth of cuttings.