Influência do ácido indolbutírico no enraizamento de miniestacas caulinar e foliar de mogno-africano (Khaya grandifoliola C. DC.)

The objective of this work was to evaluate the effect of concentrations of indolebutyric acid (IBA) on rooting of stem and leaf minicuttings of Khaya grandifoliola (Meliaceae), popularly known as African mahogany. Mini-stumps used were obtained from seminal origin seedlings. The minicuttings stem and leaf had length of 4 and 8 cm, respectively, with the leaf area reduced to 75%. The bases of the minicuttings were immersed in four concentrations of IBA (0, 500, 1000 and 2000 mg L-1) for 20 seconds. The experiments were installed in a completely randomized design with four treatments, three replicates and twelve minicuttings per replicate. Shortly after staking, the minicuttings were kept in a greenhouse for 90 days.  After this period, for leaf minicuttings the percentage of rooting and the number of roots were evaluated, already stem minicuttings, only six minicuttings were analyzed per repetition, evaluating the percentage of survival and rooting. The remaining stem cuttings were transferred to the shade house, where they remained for 30 days and posteriorly (120 days after staking) the percentage of survival and rooting, height, diameter of the collection, and dry mass of the aerial part and roots were evaluated. Leaf minicuttings were not considered suitable for the propagation of the African mahogany, since there was no development of the aerial part. For stem cuttings, the concentration of 2000 mg L-1 of IBA was the one with the highest rooting rate (72%), is recommended for the vegetative propagation by minicuttings of the species.