DIVERSIDADE GENÉTICA E CONSERVAÇÃO DE Tabebuia aurea (SILVA MANSO) BENTH & HOOK. F. EX S. MOORE (BIGNONIACEAE), UMA ESPÉCIE ARBÓREA DO CERRADO

Abstract

Tabebuia aurea is a tree widely distributed in the Cerrado and that is subject to the deleterious effects of fragmentation of this biome. In this work, were studied 237 samples from 12 populations of Tabebuia aurea based on the variation of 11 microsatellite loci, in order to analyze the genetic diversity and structure and test the causes of differentiation of populations. Tabebuia aurea has high genetic diversity in all populations with 379 alleles found an average of 34.4 alleles per locus, the population had an overall average of 11.89 alleles revealing a high information content associated with microsatellite markers. The average values of expected heterozygosity (He) and observed (Ho) found for the loci were 0.894 and 0.692 respectively. The inbreeding coefficient within populations ranged from 0.075 to 0.337 at the EGM in PAN, all figures are significant, P <0.00038 with a confidence interval of 95%, indicating that the allele frequencies are not following the expected proportions for balance Hardy- Weinberg equilibrium, namely, what is occurring mating between related individuals. The population of the Ecological Station of Águas Emendadas (AGE), in permanent preservation area, showed the greatest genetic diversity. The other populations in areas of permanent preservation, Emas National Park (ENP) and the APA Rio Pandeiros (PAN), did not show greater genetic diversity than other areas in the agricultural matrix fragments. However, the inbreeding coefficient was higher in areas most affected by human disturbances when compared to the conservation area. The differentiation between populations is low, but significant (θ = 0.061, P = 0.0005), (F = 0.264, P = 0.0005) (f = 0.216, P = 0.0005). Θ values were lower than those of values RST, indicating that the alleles are more likely to be identical by descent by state. The pattern of genetic isolation by distance was tested by correlating the genetic distance matrix with the matrix of geographical distance and was inefficient for the discrepancy found between populations. The non-random mating tooth and between populations, the distribution pattern of T. aurea in groups and pollination at short distance, probably are the factors responsible for genetic structure in T. aurea.