Diversidade genética em bacabeiras (Oenocarpus bacaba Mart. e Oenocarpus distchus Mart.) de diferentes procedências do Estado do Pará com base em caracteres morfoagronômicos.

Abstract

The objective of the study was to estimate and evaluate the genetic parameters between and within provenances of O. bacaba and O. distichus in the state of Pará using morphoagronomic descriptors, to provide information on the conservation and management of these species. In O. bacaba, 43 individuals from Baião and Terra Santa were evaluated for eighteen characters: three from the plant, six from the bunch and nine from the fruit. For O. distichus, fifteen characters were measured in 62 individuals from Marabá, Belém, São João do Araguaia and Baião sources: three from the plant, four from the bunch and eight from the fruit. Data were submitted to univariate and multivariate analyses, the latter being by cluster analysis via Euclidean distance and dendrogram plotting by the complete linkage method and principal component analysis. For the two species, the minimum number of measurements necessary for an efficient field collection process was estimated using the repeatability coefficient by four different methods. For O. bacaba the greatest divergence was found between TS-22 from Terra Santa and BAI-8 from Baião. Individuals of this species were grouped into six divergent groups. The characters weight of one hundred fruits and number of rachillas per bunch had the greatest contributions to the divergence between provenances, with the first four components absorbing 63.40% of the accumulated variation. In the case of O. distichus, the greatest divergence occurred between two individuals from Belém, BEL-11 and BEL-8, with the formation of seven distinct groups. The characters weight of one hundred fruits and number of rachillas per bunch also presented the greatest contributions to the divergence of O. distichus, in which the first three main components concentrated 66.16 % of the accumulated variance. The repeatability coefficients estimated for the six characters in O. bacaba and O. distichus showed different results by the four methods, with the principal components being the one with the best prediction. For an efficient process of field collection in the two species of bacaba palm, eleven measurements in the individuals of O. bacaba, and four in O. distichus are considered as the ideal number for the evaluated characters to reach a level of 90% of determination, in spontaneously occurring areas.