Resumo

LOPERA-BARRERO, N. Mauricio et al. Genetic diversity and reproductive contribution of Brycon orbignyanus offspring in the semi-natural reproductive system, using microsatellites markers. Agrociencia [online]. 2010, vol.44, n.2, pp.171-181. ISSN 2521-9766.

The conservation of genetic variability is a priority for fish lots used in restocking programs in rivers, especially for threatened or endangered fish species as is the case oí Brycon orbignyanus. The objective of this study was to estimate the genetic diversity and reproductive contribution of an offspring of B. orbignyanus used in stock programs in a semi-natural reproductive system using microsatellite markers. Samples of caudal fin from 24 breeders (12 and 12), and 95 larvae of their offspring. Breeders and offspring showed two alíeles, absence of low frequency alíeles and an average heterozygosity of 0.470 and 0.510. The coefficient F_is showed that there was no inbreeding in breeders and offspring (-0.116 and -0.242) and there were no differences (p>0.01) in the Hardy-Weinberg equilibrium. According to the analysis of molecular variance (AMOVA), most of the variation observed was within each group and not among groups, being confirmed by the Shannon index value (breeders = 0.477; offspring = 0.491). The genetic diversity in the offspring was preserved and the presence of multiple paternity and reproductive dominance was verified in 50 % of the offspring through the use of the semi-natural reproductive system.

Palavras-chave : Brycon orbignyanus; conservation; reproductive management; microsatellite; paternity; stock programs.

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