DESCRIPTION OF GENETIC DIVERSITY OF NATURAL POPULATIONS OF BARBATIMAO Stryphnodendron adstringens (Mart.) Coville IN CONSERVATION AREAS FROM MINAS GERAIS

The aim of this study was to describe the genetic diversity of S. adstringens in three populations from protected areas of Minas Gerais State, Brazil, by using isozymes. We sampled populations from State Parks (SP) Biribiri and Serra Nova, and National Park (NP) Sempre Vivas. We used 14 isozyme markers, which among them nine loci were polymorphic (est-2, est-3, est-4, got-1, pgi-1, mdh-4, idh-1, adh-1 and skdh-1). The adjustment tests to EHW genotypic proportions, Fisher's exact test and chi(2), were not significant to the isozyme loci in the three populations, except est-4 in SP Serra Nova, mdh-4 and idh-1 in SP Biribiri. The values of average expected heterozygosity (H e) ranged between 0.217 to 0.255, and are close to those found in tropical tree species (0.204 to 0.211) with the same characteristics of geographical distribution of S. adstringes. The fixation index (F) were significantly lower than zero in the population of SP Biribiri (-0.149), and not significantly in the NP Sempre Vivas (-0.031) and SP Serra Nova (-0.138). The significant excess of heterozygotes in SP Biribiri population may be an indicative of selection in favor of these genotypes, however, to verify this possibility, further studies are required, considering environmental variables.