The objective of this work was to study the genetic diversity of pacu samples from the middle Paranapanema River and from the broodstock used in the stock enhancement program of the Aquaculture and Hydrology Station at the Duke Energy Power Plant, by RAPD marker. Fourteen primers were used to analyze 30 individuals captured in the middle Paranapanema River and 29 individuals from the broodstock. The Shannon genetic diversity index and percentage of polymorphic fragments were higher in individuals captured in the Paranapanema River. Genetic similarity was larger in individuals of the broodstock. Results of analysis of molecular variance showed that the major part of the genetic variation is within the groups (84.2%) and not between them (15.8%). The identity and genetic distance among the groups were 0.9517 and 0.0549, respectively. Moderate genetic differentiation (F ST = 0.15) and high number of migrants per generation (Nm = 5.33) were observed between the two groups. The genetic diversity was lower in the broodstock than in fish captured in the middle Paranapanema River.
Piaractus mesopotamicus; RAPD; molecular markers; genetic variability
