Resgate e propagação vegetativa de Eremanthus erythropappus (DC.) MacLeish em povoamentos naturais

Abstract

The natural forest of candeia [Eremanthus erythropappus (DC.) MacLeish] have been explored throught Sustainable Manegament Forestry due to economic potencial of the essencial oil, extracted by distillation of wood. The vegetative propagation could be useful to rescue adult trees and conserve superior genotypes, as well as the application of silvicultural techniques that favor the restoration of the explored area, can assure the genetic resources . In this study , the efficiency of sprout method in matrices of candeia was tested in natural forest management. Thus, in August 2017, twenty-six trees were induced to sprout by cutter, followed by exposure and scarification of the roots on the ground. The emergence of new shoots was evaluted according with source (stump or root) at the intervals of 30, 60, 90, 120, 157 and 189 days after induction (DAI). At each interval, the number of shoots and the growth in height and diameter of base were measured by plant. At 189 DAI, the technique provides coppicing of 76.92% of trees, resulting 396 shoots, only radicular source. The percentage of genotypes sprouted, number of shoots per plant, height, diameter and shoot height / diameter ratio increased over the evaluated period. Subsequently, the propagation methods by epicormic shoots and by cutting were tested. For the epicormic shoots, six branches of five tree stands were selected from a natural forest and, after being standardized at 0.50 m in length, so the branches were conditioned in a greenhouse with humidity of 80% and the temperature mantained between 25- 35 °C. After seventy days no twig sprouted. The cutting experiment was conducted with sprouted collected from nineteen genotypes from field, so apical cuttings with 7.5 – 12.0 cm length were made. Indole-3-butyric acid (IBA) was applied at the base of the stake at 4 g L -1 concentration and compared to the control treatment, which was characterized by the absence of IBA. Only 12.2% of the cuttings survived SCV, and of these, 7.9% rooted in the shade house, regardless of the treatment applied. Even with the low percentage of survival recorded, the cutting was more efficient than the propagation by epicormic shoots, enabling the formation of a clonal mini-garden of candeia with 7 of the 19 genotypes submitted to propagation. Absence of IBA resulted in higher percentage of survival when compared to the concentration of 4 g L -1 . With the results obtained in this work it’s possible conclude that the sprout method applied was efficient in promoting shoots of candeia, even under natural conditions and that IBA concentration wasn’t adequate for the formation of adventitious roots.