Variabilidade genética de larvas e alevinos de piracanjuba (Brycon orbignyanus) / Genetic variability of larvae and fingerlings of Piracanjuba (Brycon orbignyanus)

O objetivo do presente trabalho foi avaliar a variabilidade genética de larvas e alevinos de piracanjuba em programa de repovoamento. Foram coletadas 180 larvas de piracanjuba de três dias e 90 alevinos de três meses de idade. Foram avaliados cinco loci microssatélites, os quais produziram 19 alelos. Não houve presença de alelos raros nem perdas de alelos ao longo do período. A heterozigosidade observada foi superior nas larvas em relação aos alevinos. Houve desvio no equilíbrio de Hardy-Weinberg na maioria dos loci em ambos os grupos. O coeficiente de endogamia foi positivo em ambos os grupos, sendo a média dos alevinos superior em relação às larvas. O excesso de heterozigotos foi significativo no modelo Stepwise Mutation Model para os alevinos, indicando a possibilidade de efeito gargalo recente. Conclui-se que, apesar da adequada variabilidade genética encontrada, os valores do coeficiente de endogamia e a possibilidade de efeito gargalo nos alevinos atentam para a necessidade de constante monitoramento genético desses estoques antes da liberação no ambiente.(AU)

The objective of this study was to evaluate the genetic variability of Piracanjuba larvae and fingerlings in restocking program. A total of 180 three-day Piracanjuba larvae and 90 three-month-old fish were sampled. Five microsatellite loci were evaluated, which produced 19 alleles. There were no rare alleles or loss of alleles over the period. The observed heterozygosity was higher in larvae compared to fingerlings. There was a deviation in Hardy-Weinberg equilibrium in most loci in both groups. The inbreeding coefficient was positive in both groups, with the average of the fingerlings superior to the larvae. The excess heterozygotes were significant in the Stepwise Mutation Model for the fingerlings, indicating the possibility of a recent bottleneck effect. Despite the adequate genetic variability found, the values of the inbreeding coefficient and the possibility of bottleneck effect in the fingerlings show the need for constant genetic monitoring of these stocks prior to release into the environment.(AU)

Genetic variability and resistance of cultivars of cowpea [Vigna unguiculata (L.) Walp] to cowpea weevil (Callosobruchus maculatus Fabr.).

The cowpea weevil (Callosobruchus maculatus Fabr.) is the most destructive pest of the cowpea bean; it reduces seed quality. To control this pest, resistance testing combined with genetic analysis using molecular markers has been widely applied in research. Among the markers that show reliable results, the inter-simple sequence repeats (ISSRs) (microsatellites) are noteworthy. This study was performed to evaluate the resistance of 27 cultivars of cowpea bean to cowpea weevil. We tested the resistance related to the genetic variability of these cultivars using ISSR markers. To analyze the resistance of cultivars to weevil, a completely randomized test design with 4 replicates and 27 treatments was adopted. Five pairs of the insect were placed in 30 grains per replicate. Analysis of variance showed that the number of eggs and emerged insects were significantly different in the treatments, and the means were compared by statistical tests. The analysis of the large genetic variability in all cultivars resulted in the formation of different groups. The test of resistance showed that the cultivar Inhuma was the most sensitive to both number of eggs and number of emerged adults, while the TE96-290-12-G and MNC99-537-F4 (BRS Tumucumaque) cultivars were the least sensitive to the number of eggs and the number of emerged insects, respectively.