Aspects of the mating system and genetic diversity in a native population of Copaifera multijuga Hayne in the Western Amazon

Copaifera multijuga Hayne is an Amazonian species that has been the target of intense exploitation due to its oleoresin. This raw material has a high value in various economic segments such as perfumery and cosmetics. However, there are few investigations  aimed at characterizing the genetic parameters in native populations of this species. In this sense, our objective was to estimate the genetic diversity and characterize the mating system of C. multijuga found in a native population in the Western Amazon. Wood samples were collected from 48 adult trees for the population study. Among these, 15 trees were selected to compose the group of maternal parents of the reproductive system study, for which leaf samples were collected from 20 open-pollinated seedlings (offspring), which were obtained using natural regeneration (n = 300). Using five pairs of heterologous microsatellite primers, the main parameters of genetic diversity and mating system were estimated: observed (H_o) and expected (H_e) heterozygosity, total number of alleles (A), fixation index (f), multilocus (t_m) and single-locus (t_s) outcrossing rates, etc. The population showed levels of genetic diversity greater than 0.6 both in the adult trees (H_o: 0.742; H_e: 0.743) and in the offspring (H_o: 0.685; H_e: 0.685). Mating occurred predominantly by outcrossing (t_m: 0.88–1.00), of which 4.1% corresponded to mating between relatives (t_m–t_s). The results obtained in this study are fundamental for the investigation of the possible impacts of exploitation on the genetic diversity of native populations and, consequently, so that conservation strategies are properly planned.