Avaliação da diversidade genética de plantios de Aniba rosaeodora Ducke em municípios do Amazonas a partir de marcadores microssatélites

Abstract

Aniba rosaeodora Ducke (Lauraceae), popularly known as rosewood, is an Amazonian essential oil-producing forest species of great economic importance. Due to the predatory nature of its exploitation in the past, natural populations of A. rosaeodora been drastically reduced and the species it is now considered endangered. There is low genetic knowledge about A. rosaeodora and even less about the effects of its exploitation over the years on the diversity and genetic differentiation of its populations. The aim of this study was therefore to characterize the levels of genetic diversity conserved in A. rosaeodora plantations using microsatellite markers (Simple Sequence Repeats - SSR). To our best knowledge, this is the first study to genetically evaluate rosewood plantations using SSRs. Thirty-two trees with a DBH>15 cm (Diameter at Breast Height) were selected and sampled in two plantations located in the municipalities of Maués and Manaus, both in the state of Amazonas (N=64). Leaf samples collected for the extraction, amplification and genotyping of genomic DNA. Using nine species-specific microsatellite markers, the main genetic diversity parameters estimated: observed heterozygosity (Ho) and expected (He) heterozygosity, total number of alleles (A), fixation index (f), etc. High levels of polymorphism (PIC>0.7) and genetic diversity were detected in both the trees from the commercial plantation in Maués (Ho: 0.743; He: 0.813) and the experimental plantation in Manaus (Ho: 0.844; He: 0.838). The presence of 12 and 18 exclusive alleles verified in the plantations in Maués and Manaus, respectively. The Fst index (0.074; P < 0.001) indicated significant genetic differentiation distributed between the two plantations, which was confirmed by the Structure program, with the formation of three genetic clusters (K=3). Knowledge of the size and breadth of the genetic diversity available in A. rosaeodora plantations could help in the selection of matrices for seed collection in order to establish new plantations of the species. In addition, the results may contribute to the adoption of appropriate conservation strategies for the species, encouraging investment, increasing productivity and reducing pressure on natural populations.