Repetibilidade e número mínimo de avaliações para caracteres de frutos de oenocarpus bacaba mart. em áreas de ocorrência natural do estado do Pará.

Abstract

The bacaba palm (O. bacaba Mart.) is a species native to the Amazon, but not endemic, being found naturally in dry land and floodplain forests in northern Brazil. The objective of this work was to determine the repeatability coefficient and minimum number of evaluations necessary for O. bacaba fruits characters in areas of natural occurrence in the State of Pará, with a view to assisting in the efficient collection process. Forty-four samples of ripe fruit obtained from collection expeditions carried out in three municipalities were useds: Baião, Marabá and Terra Santa. Five fruits of each sample were evaluated for eight characters: longitudinal (DL) and transverse (DT) diameters, pulp (EP) and almond (EA) thicknesses, all expressed in mm; fruit (PF), edible part (PP) and seed (PS) weights, obtained in g; and yield of the edible part (RPF), involving the epicarp + mesocarp, in percentage. Estimates of repeatability coefficients (r) were obtaineds using four methods: analysis of variance (ANOVA); principal components, based on the matrix of correlations (CPC) and covariances (CPCV); and structural analysis based on the correlation matrix (AE), in Software Genes. Repeatability coefficients ranged from 0.24 for pulp yield per fruit to 0.81 for longitudinal diameter. The longitudinal (DL) and transverse (DT) diameter characters had high magnitudes (<0.60), with values of 0.81 and 0.66-0.67, respectively. The minimum number of fruit evaluations to predict actual values ranged from 1 to 18; 2 to 28; 4 to 60 fruits with 85%; 90%; 95% reliability respectively. It is believed that samples containing nine fruits are necessary to obtain a coefficient of determination of 90% in seven of the eight characters evaluated in this study.