Caracterização física e bioquímica de frutos de Caryocar brasiliense (pequizeiro) com e sem espinhos no endocarpo e abordagens biotecnológicas para a conservação e micropropagação in vitro

Abstract

The pequi presents considerable variability in morphological, physical and chemical characteristics, however, there is scarce data in the literature for species without spines in the endocarp. The aim of this study was to evaluate the genetic diversity of a population of pequi trees that produce fruits with and without spines in the endocarp by analysis of morphological characters, to quantify the nutritional composition of pequis and to study the processes of in vitro regeneration of the species. 17 matrices were studied, 8 of which produce fruit with spines and 9 fruit producers without thorns, cultivated at Fazenda Água Limpa Experimental Station, Federal University of Uberlândia. Initially the weight, height, length and width of the fruit were determined; weight, height, length, diameter and yield of the pyrenes; weight and peel thickness, and yield of pulp. The peel, pulp and almond had their composition centesimal, pigments and physical-chemical properties evaluated. For in vitro regeneration experiments, disinfection, oxidation control and regeneration of leaf explants were carried out using different concentrations of growth regulators. It was verified that from fruit characters it was possible to evaluate the genetic diversity between the matrices. The grouping methods used were efficient in the characterization of distinct groups, classifying in three groups by the Tocher method, five groups by the UPGMA method and eight groups by the Principal Components method. Analysis of the clustering methods showed that the matrices B29 and D8 constituted individual groups, revealing the potential of these matrices for future genetic breeding program. The pequi pulp is high in lipids, carotenoids and carbohydrates, with energy value of 19.05% and 28.37% for fruits with and without spines, respectively. Among the pigments, β-carotene was determined high quantities in fruits with spines in the endocarp. Significant differences (t-test, p≤0.05) among the groups of pequis based on morphological characters and nutritional composition. Was observed the viability was observed in vitro regeneration of the leaf explants for the formation of calluses and roots when submitted to different concentrations of auxins and cytokinins in WPM culture medium.