Mating system in a natural population of Theobroma grandiflorum (Willd. ex Spreng.) Schum., by microsatellite markers.

The aim of this research was to study the mating system of a natural population of Theobroma grandiflorum (cupuassu) from Nova Ipixuna, Pará state, using microsatellite markers. Eight polymorphic microsatellite loci were analyzed in eight families, each represented by 10 six-month old seedlings derived from open-pollinated pods. The estimation for the multilocus outcrossing rate ($tm= 1.0) and individual outcrossing rate ($t= 1.0) for this population suggests that T. grandiflorum may be a perfect outbreeding (allogamous) species. Likewise, for the studied population the estimate for single locus outcrossing rate ($ts) was elevated (0.946), but lower than$tm, confirming the likely outcrossing character of the species and suggesting the occurrence of 5.4% biparental inbreeding rate ($tm-$ts). The estimation of genetic divergence ($FST) between allelic frequencies in ovules and pollen revealed a deviation from random mating in 75$rp= 0.930) and the mean coefficient of co-ancestrality within families ($?xy= 0.501) indicated that the outcrossings were predominantly correlated, and the offspring were full-sibs. These results suggested that for this particular population of T. grandiflorum, the sampling strategy for genetic conservation and breeding should adopt specific models for families derived from correlated outcrossing (full-sibs) and not the ones usually adopted in classic outcrossing species breeding programs (half-sibs)

Diversidade genética entre clones de cupuaçuzeiro com o uso de marcadores moleculares do tipo microssatélites.

Programa Institucional de Bolsas de Iniciação Científica (PIBIC). Disponível também on-line

Polinização efetiva em pomar de Ilex paraguariensis St. Hil.

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Caracterização genética de procedências e progênies de Ilex paraguariensis St. Hill. utilizando marcadores RAPD.

Ilex paraguariensis St. Hil. é uma arbórea nativa do Brasil, Paraguai e Argentina, onde apresenta grande importância sócio-econômica. Com a crescente demanda e a redução dos ervais nativos, o plantio surge como uma solução para o atendimento do mercado. Porém, devido à escassez de estudos genéticos e de programas de melhoramento, as sementes utilizadas para a formação de novas populações não apresentam boa qualidade, resultando em ervais com baixa produtividade. Informações sobre a variabilidade genética são de extrema importância para nortear os programas melhoramento e conservação dos recursos genéticos da espécie. Esse trabalho teve por objetivo determinar a variabilidade genética em um teste de procedências e progênies de I. paraguariensis, utilizando marcadores RAPD. Para isso, utilizaram-se folhas jovens de três procedências do estado do Paraná: Ivaí, Pinhão e Cascavel, do teste de procedências e progênies, localizado no município de Ivaí. Os quinze primers empregados produziram 159 fragmentos, sendo 70,4% polimórficos. As distâncias genéticas entre as procedências e progênies foram baixas. Verificou-se maior variação dentro das procedências (88,3%) do que entre procedências (11,7%). A maior parte da variação dentro de procedências foi devido a diferenças genéticas entre as progênies (55,5%). Os resultados sugerem que, devido ao fato da maior variação genética estar entre progênies, maiores ganhos podem ser obtidos pela seleção entre progênies do que entre procedências

Mendelian inheritance, linkage and genotypic disequilibrium in microsatellite loci isolated from Hymenaea courbaril (Leguminosae).

The Neotropical tree Hymenaea courbaril, locally known as Jatobá, is a valuable source of lumber and also produces comestible and medicinal fruit. We characterized Mendelian inheritance, linkage and genotypic disequilibrium at nine microsatellite loci isolated from H. courbaril, in order to determine if they would provide accurate estimates of population genetic parameters of this important Amazon species. The study was made on 250 open-pollinated offspring originated from 14 seed trees. Only one of nine loci presented significant deviation from the expected Mendelian segregation (1:1). Genotypic disequilibrium between pairwise loci was investigated based on samples from 55 adult and 56 juvenile trees. No genetic linkage between any paired loci was observed. After Bonferroni’s corrections for multiple tests, we found no evidence of genotypic disequilibrium between pairs of loci. We conclude that this set of loci can be used for genetic diversity/structure, mating system, gene flow, and parentage analyses in H. courbaril populations

Mendelian inheritance, linkage and genotypic disequilibrium in microsatellite loci isolated from Hymenaea courbaril (Leguminosae).

The Neotropical tree Hymenaea courbaril, locally known as Jatobá, is a valuable source of lumber and also produces comestible and medicinal fruit. We characterized Mendelian inheritance, linkage and genotypic disequilibrium at nine microsatellite loci isolated from H. courbaril, in order to determine if they would provide accurate estimates of population genetic parameters of this important Amazon species. The study was made on 250 open-pollinated offspring originated from 14 seed trees. Only one of nine loci presented significant deviation from the expected Mendelian segregation (1:1). Genotypic disequilibrium between pairwise loci was investigated based on samples from 55 adult and 56 juvenile trees. No genetic linkage between any paired loci was observed. After Bonferroni’s corrections for multiple tests, we found no evidence of genotypic disequilibrium between pairs of loci. We conclude that this set of loci can be used for genetic diversity/ structure, mating system, gene flow, and parentage analyses in H. courbaril populations