EVALUATION OF DIVERSITY AND GENETIC STRUCTURE AS STRATEGIES FOR CONSERVATION OF NATURAL POPULATIONS OF Dalbergia nigra (Vell.) Allemão ex Benth.

The ISSR molecular diversity to high genetic nigra . Most of the genetic diversity influenced by individuals from Flona of Pacotuba. The evaluated populations structured. ABSTRACT: The evaluation of diversity and genetic structure allows us to verify with precision the effect of evolutionary and anthropic processes on species. The objective of this research was to evaluate the divergence and the genetic structure of two natural populations of Dalbergia nigra , using molecular markers Inter Simple Sequence Repeats (ISSR). Leaf samples were collected from two populations, located in the National Forest of Pacotuba and the Private Natural Heritage Reserve of Cafundó. Eight ISSR primers were used, which resulted in 97 bands, with 68.04% of polymorphism. Based on the joint data, the values of 0.33 for the Nei index (H*) and 0.50 for the Shannon index (I*) indicated moderate to high genetic diversity, being influenced by the presence of genetically dissimilar individuals in the National Forest of Pacotuba. Most of the genetic divergence was intrapopulational (85.96%), with moderate differentiation between populations ( Φ ST = 0.1404). The estimated historical gene flow between the fragments was low (N m = 3.21) when compared with results from other tree species, and the genetic structuring analysis separated the populations into two groups, corresponding to the two populations evaluated. The results indicate a small genetic share among populations, however, populations are becoming structured. The satisfactory levels of genetic diversity benefit the use of the trees as matrixes for programs of restoration and recovery of degraded areas, connectivity of landscapes, and sustainable use of forest resources.