Diversidade genÃtica de Myrcia splendens (SW.) DC. (Myrtaceae) por marcadores ISSR em sistema corredor-fragmento semideciduais no Sul de Minas Gerais / Genetic diversity of Myrcia splendens (SW.) DC. (Myrtaceae) by ISSR markers in a system semidecidual corridor-fragment in the South of Minas Gerais

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

In the South of Minas Gerais State, the landscape is mainly characterized by fragmented ecosystems. So, the presence of vegetation corridors has a great ecological importance gene flow of plants and animals. In the regional the corridors are narrow, between 3 and 6m and resulted from secondary vegetation colonization trenches, built for land division purposes. These corridors interconnect remaining fragment of primary forest. One of the most abundant species in these environments is Myrcia splendens, which has zoocoric dispersion, known as guamirim or folha-miÃda. Therefore, this work aimed to access the genetic variability of M. splendens populations in primary formations (fragments) and in secondary formations (corridors). The genetic variation was assessed with 70 polymorphic loci using ten ISSR primers. The genetic structure of the species was carried out using a sample of 168 individuals distributed in five fragments and 104 individuals distributed in four corridors. The results indicated high genetic diversity of the species in the fragments (He = 0.37; I =0.53) and in the corridors (He = 0.33; I =0.48). AMOVA revealed that most of the genetic diversities of M. splendens were found within the populations (96.49% in the fragments and 91.15% in the corridors). The gene flow for the set of fragments studied was high (Nm = 8.7). In general, the fragments presented higher gene flow with neighboring corridors. Low differentiation among fragments and no significative correlation between genetic and geographic distance (r = 0.057; P = 0.43) was observed. The primary formations (F1 to F5) and the corridors C1 and C2 revealed that genotypes were randomly distributed. Positive spatial autocorrelation was detected in the corridors C3 and C4 with values of positive coancestry in the first distance class (Sp = 0.012 and 0.014, respectively). In the analyzed landscape, the vegetation corridors had a great importance to minimizing the negative effects of fragmentation. Therefore, maintaining the corridors is a valuable measure for conservation of the species and the forests remnants.

ASSUNTO(S)

1. diversidade genÃtica. 2. myrtaceae. 3. myrcia splendens. 4. issr. recursos florestais e engenharia florestal

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