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Outcrossing rate and mating system of a natural population of Copaifera langsdorffii Desf. in the region of Lavras, MG, starting from isozyme

A natural population of the tree species Copaifera langsdorffii Desf., commonly found in Brazil, was investigated by isozyme electrophoresis, aiming to determine the outcrossing rate and mating system. The population sampled is located along a stretch of the river Capivari in an area of preservation (Riparian Forest), between the towns of Lavras and Itumirim, south of Minas Gerais State, Brazil. Samples of leaf tissue were taken from 20 adult individuals and from 400 progenies for isozyme analysis. Five enzymatic systems were evaluated in adults (24 alleles average) and progenies (29 total alleles). The mating system of this population was approached by the Hardy-Weinberg equilibrium test (HWE) where it was found that most loci of the adult individuals is in the ratios of the HWE and most loci of the progenies is out of the it. The estimate of the average multilocus (t m) and unilocus outcrossing rate (t s) was respectively 0.917 and 0.877, pointing out the existence of self-fertilization (8%) in the population studied. The results obtained by isozymes analyses indicated also that the species Copaifera langsdorffii is predominantly alogamous. The population has relatively high genetic variation making this population of C. langsdorffii a valuable source for genetic conservation. The minimum area size estimated for the in situ conservation was 5.0 ha.

Copaifera langsdorffii; isozymes; Hardy-Weinberg Equilibrium


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