Diversidade genética entre e dentro de populações de Astrocaryum acaule Mart. (ARECACEAE)

Abstract

Astrocaryum acaule Mart. (Arecaceae) has edible fruits, the seed is used for the manufacture of biojóias, the leaves for fiber extraction. With the subterranean stem, this species can be targeted in the interspecific improvement with A. aculeatum to reduce the size of this important palm of the Amazon. The objective of this study was to evaluate the genetic diversity among and within populations of A. acaule by means of AFLP markers. The three populations studied were located in the city of Manaus, and samples of 30 plants were collected from each population. Three primer combinations were selected for the analysis: E + ACA / M + CGC, E + AAC / M + CAC and E + AAC / M + CGA. The percent of polymorphics locis was estimated, Analysis of Molecular Variance performed, dendrogram builded and the populational differentiation and substructuration genetics patterns checked. The dendrogram generated on the basis of the arithmetic complement of the Jaccard genetic distance and the UPGMA grouping method of the 90 subsamples of A. acaule revealed that the individuals in the Tarumã-Açu population stand out as being genetically different from the other two populations, UFAM and Tupé, and the Dendrogram obtained based on the genetic distance of Nei confirms this information. The values of expected heterozygosity (He) and the genetic diversity index of Shannon and Weaver (I) did not show large variations among the three populations. However, the highest values of He (0.2169) and I (0.3413) were found in the Tarumã-Açu population, indicating greater genetic diversity within this population. These results were already expected, as this population is more propitious to receive genetic material from other regions and, therefore, the individuals that compose it have greater genetic variability. The result of the Molecular Analysis of Variance attributed 25.42% and 74.58% of the variation between and within the populations, respectively. Thus, plans of use and conservation of the species must observe the genetic variability found in these populations, in order to guarantee the conservation of their genetic resources. Molecular markers of the AFLP type reveal high content of genetic information in A. acaule and can be used for genetic analysis, aiming to obtain information for genetic sustainability and species management. The distribution of genetic diversity in the studied populations of A. acaule is greater within the populations than among them, and it is necessary to obtain representative samples of each of the genetically distinct groups for the genetic conservation of the species.