Variações entre procedências de Toona ciliata M. Roemer var. australis quanto a taxa de crescimento e armazenamento de carboidratos não estruturais na madeira

Abstract

Trees have adaptive capacities that in the face of environmental stresses, modify their structures whose necessary is survival. Non-structural carbohydrates (NSC) are presented as a beaconing tool in addition to a phytosanitary status of the tree, a precursor for the genetic sel ection of resilients progenies. Such carbohydrates have the fundamental function in the survival of the plant to repair the embolism in the xylem, recovering the duct for the ascending flow of crude sap and keeping active the hydraulic flow of the plant. The objective of the study was to select higher progenies by analyzing the contents of non-structural carbohydrates (starch, sucrose, reducing sugars, total sugars and total non-structural carbohydrates), generate a new quantification protocol and identify the radial variation pattern of CNE's and their relationships with the environmental variables of origin. A total of 71 progenies from 16 different origins were selected, and one progeny per origin was selected after genetic tests using REML / BLUP from the selegen statistical software. Carbohydrate prediction models were calibrated by means of partial least squares regression for the validation of non - structural carbohydrate prediction using near infrared spectroscopy (NIRS) by chemoface statistical software. The environmental parameters used in the study were the magnitude of drought and maximum, minimum and average temperatures of the australian east coast origin. By deviance test there was a significant effect of provenance and progeny, validating that there is difference between evaluated genotypes. The coefficient of individual addit ive genetic variation was 1.0049 reaffirming the viability in the selection. The lowest coefficient of determination calculated on the external validation by the NIRS was for the starch R² = 0.80. The ratios between dryness, temperature and non - structural carbohydrates were all statistically significant. It was observed that the minimum temperatures and the maximum values of drought magnitudes exert a greater influence under the NSC contents, so that the progenies 5, 15 and 16 could be selected for the stress sites.