Produção de mudas clonais de Tectona grandis (Linn f.) em diferentes sistemas de minijardim

Abstract

The Tectona grandis species has occupied more space among the exotic species planted in Brazil and abroad, due to its high quality of timber. For its rapid propagation it is recommended the use of superior genotypes, coming from genetic breeding programs, for that, it’s necessary the constant improvement of seedling production techniques to obtain clonal seedlings with quality and greater survival in the field. Based on this, the general objective of this work was to evaluate, during successive collections and anatomical images, the best mini-garden system, canaletão (SC) or tubete (ST), for production of clonal changes of T. grandis. The clonal seedlings were planted in the two systems of mini-garden and 10 days the pruning was done apical for emission of shoots. The mini-cuttings were collected for each mini-garden system with 7sete cm of length, leaves reduced to 25% of the original size, cut of the bevel base and posterior were staked with addition of powdered indolbutyric acid to 500 mg. L-1. As variables, the productivity of mini-cuttings, remaining shoots, mini-stumps survival, nutritional analysis, root number, total root length, length of the largest root, survival of seedlings, height, diameter, dry mass (root, aerial and total), Dickson quality index and height / diameter ratio. During the eight months of the experiment, eight samples were collected in canaletão system and four in a tubete system, both mini-garden presented survival above 94 %. The mini-stumps of T. grandis show cyclic behavior. The mini-garden system in canaletão (0.62 mini-cutting/mini-stumps) presented higher productivity in relation to the tubete system (0.56 mini-cutting/mini-stumps). As well as better radicial force, nutritional analysis, survival in greenhouse, shade house and full sun, and quality of seedling. The second experiment followed the steps described previously to carry out the staking, and the seedlings were taken to greenhouse and evaluated every 10 days in the rhizogenic behavior, calogenic and rooting percentage for 40 days, and anatomical images of both mini - gardens. The mini-cutting from the minigarden tubete were more lignified, higher calogenic percentage, the presence of fibers, higher secondary growth and root emission, however the root behavior was the same for both mini-garden systems, and there was no statistical difference starting the 30 days of stacking. Therefore, it was concluded that the best mini-garden was in canaletão system, presenting better results for the production and quality of changes.