Genetic diversity and structure of Varronia curassavica Jacq. populations in the restinga of Santa Catarina Island

ABSTRACT

The Varronia curassavica Jacq. (Boraginaceae) is present in restinga vegetation and shows relevant medicinal properties. The species is exploited by local communities and by the pharmaceutical industry; however, it lacks ecological and genetic information. Thus, this study aimed to characterize the genetic diversity of three V. curassavica populations in restinga areas of Santa Catarina Island. Leaves of 50 adult individuals were sampled in each of the three study areas and the allelic frequencies were obtained from 14 allozyme loci. Twenty-five different alleles were found in the three populations, two of them being exclusive. The populations showed, on average, a genetic diversity of 0,111 and a fixation index of -0,060 (-0,273 to 0,222). The diversity levels are intermediary, similar to those ones owned by species of the same family or with similar ecological traits. The fixation indexes were all significant and discrepant among the populations, with two of them showing excess of heterozygotes. The genetic divergence among populations was significant and equal to 0,079, which is considered moderate and suggests effects of population subdivision. The levels of genetic diversity found and the population decrease caused by reduction and fragmentation of habitats in which the species are present implies in ex situ conservation measures and a higher enforcement of the legal preservation of permanent protected areas.

Keywords
conservation; effective size; “erva-baleeira”; medicinal species