Resistência, capacidade regenerativa e danos resultantes da desfolha em mudas clonais de Tectona grandis L. f.

Abstract

Considering that the use of resistant genetic materials can reduce silvicultural interventions, costs, environmental problems and the little information on the consequence of defoliation in teak seedlings, this work had as objective to analyze the damages, regenerative capacity and resistance in clonal seedlings of Tectona grandis submitted to artificial defoliation of 0%, 25%, 50%, 75% and 100%. This work was developed at the Federal University of Mato Grosso, Cuiabá Campus, State of Mato Grosso, in an open nursery. The tests were carried out in seven clones, using seedlings with two months of planting in 10 L pots, being evaluated for 6 months, after the partial and total defoliation. For the analysis of damages, the height (cm) and the base plant diameter (mm), and wet matter (g) and dry matter (g) were collected at the end of the experiment. Subsequently, the loss of increment and the Mood Quality Index (IQM) were calculated. To identify the regenerative capacity, the amount of leaves before the defoliation and after defoliation were collected fortnightly. Resistance was determined through the leaf regeneration data, by means of weighted percent tolerance (PPT) equations and weighted percentage of susceptibility (PPS). The seedlings that were submitted to the highest percentage of defoliation were not those that suffered the greatest loss of height and diameter increment. The genetic materials had different results, from loss of increment to stimulus in the development of parts of the plant. The genetic factor interferes with the plant growth strategy and the seedling regenerative capacity, independent of seedling quality.