Coleta e caracterização de germoplasma de mangabeira (Hancornia speciosa Gomes) nos municípios de Salvaterra e Maracanã, estado do Pará.

Abstract

Mangaba tree (Hancornia speciosa, Gomes) is a tropical, perennial fruit plant, native to Brazil, and belonging to the Apocynaceae family. Because of the aroma and flavor of its fruits, mangaba tree has cultural and socioeconomic importance, and is being widely used in the agroindustry. Fructification can occur in any period of the year, but has its peak either from July to October or from January to April. The increased demand for mangaba tree derived-products confirms the potential of its agro and socioeconomic exploitation; however, more research is needed to solve technological problems that prevent the commercial utilization of the plant. The aim of this study was to characterize trees and fruits from natural populations of Hancornia speciosa in Salvaterra (Marajó meso-region of Pará) and Maracanã (Salgado meso-region of Pará), as well as to evaluate the magnitude and distribution of the extant phenotypic variation. Expeditions to collect mangaba tree germplasm were conducted from February to December 2011. Information was gathered based on the knowledge of agriculturists and catchers to collect georeferenced productive plants distant from one another. A total of 92 parent plants were sampled and had 18 quantitative morpho-agronomic characters measured, associated with plant (six), fruits (nine), and agronomy (three). Those morpho-agronomic characters were investigated using variance analysis with two sources of variation, between and within parent plants, in order to check for genetic variability. To evaluate genetic diversity between parent plants and classify them in similarity groups, multivariate methods, such as principal components, mean Euclidian distance, load building of Tocher, and UPGMA were employed. For the principal components analysis, a Pearson correlation matrix was used with centered and reduced data. Pearson correlation coefficient estimated phenotypic correlations between characters from parental plants to endorse the decision of discarding redundant characters in the selection method with reanalysis. Identification of redundant characters was initially performed by direct selection, followed by a gradual discarding method, selection with reanalysis. Tocher method was used to establish the formation of different parent plant groups, while UPGMA method was used in the delimitation of groups in order to construct a dendogram that could identify parent plant groups. The 92 parent plants collected in both municipalities showed phenotypic variation for the evaluated characters, providing data to breeding and domestication of the species. Based on the univariate analysis, phenotypic variability was detected for most of the morphoagronomic characters evaluated, suggesting that parent trees have variation. Selected descriptors allowed to quantify phenotypic diversity in the parent plants of this species by using standardized mean Euclidian distance, making it possible to select those of economic importance that were positive within the evaluated populations.