Potencial de resgate vegetativo da castanha-do-brasil (Bertholletia excelsa Bonpl.) a partir de brotações epicórmicas de ramos destacados

Abstract

Brazil nut (Bertholletia excelsa Bonpl.) is one of the Amazonian species most appreciated for its nutritional value, economic importance, socioenvironmental and ecological relevance. Its propagation is usually made by seeds that have certain limitations, while propagation by cutting can boost the production of clonal seedlings and / or selected material. The objective of this study was to evaluate the emission of epicormic shoots on branches live detached from the stock plant and their diameter, as well as the effect of indolebutyric acid (0 and 1000 mg.kg-1) on the rooting of cuttings from these shoots. For the shoot emission, the experimental design was a completely randomized design, in factorial scheme 6 (stock plants) x 3 (tree diameters), with four replications, each containing 5 stems. The number of shoots per stem was counted every five days and, from these data, the velocity index and average sprouting time were calculated. For the rooting of the shoots, we used the completely randomized design, factorial scheme 6 (stock plants) x 2 (cutting types) x 2 (concentrations of indolbutiric acid), with four replicates, each containing 5 cuttings, mainly evaluating survival, rooting and callogenesis. The technique of detached live branches made it possible to obtain juvenile material with potential for use in the vegetative propagation of Brazil nuts. The number of epicormic shoots and the rate of shoot speed are dependent of the association between the stock plant and the diameter of the detached branch. The higher yield in the number of epicormic shoots on the stems of larger diameter branches (20-40 and 40-80 mm) favors the obtaining of vegetative propagules with potential for use in clonal multiplication. Due to a problem in the nebulization system and possibly related to the substrate used, the cuttings results were practically null, requiring the experiment to be reinstalled, with adjustments.