Indolbutyric Acid (IBA) in the African Mahogany (Khaya grandifoliola C. DC.) cuttings and mini-cuttings development

Abstract

The current expansion of the forest sector in the Cerrado (Brazilian Savannah), especially of the species of genus Khaya sp. (African Mahogany), requires several silvicultural and technical studies of various natures. Seed and clonal propagation enable noble and vigorous seedlings, which will future compose commercial plantations aiming timber production. The species Khaya grandifoliola C. DC is considered of distinct wood features and with great economic potential. The objective of this work was to evaluate the effect of different indolbultyric acid (IBA) concentrations – between 0 and 12 g.L-1 – on the rooting of K. grandifoliola cuttings (clonal origin) and mini-cuttings (seed origin). The experiment was carried out at the "Mudas Nobres" private nursery, located in Goiânia (Goiás State, Brazil). The experiment was conducted in a completely randomized design in a 5 × 2 factorial scheme. Multivariate, Neural Networks and Random Forest models were also applied to estimate the number of shoots in clonal cuttings, according to the data observed in seed mini-cuttings. The results indicate that IBA has the opposite effect on the two evaluated types of propagule origin, being more suitable for seed mini-cuttings (should apply 8 g.L-1 of IBA) and less suitable for clonal cuttings (should not apply IBA). In the operational nursery routine, if a standard application must be recommended (to cuttings either mini-cuttings), the most appropriate concentration is 6 g.L-1 of IBA.