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URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11845
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Item Detection of QTL associated with rust resistance using IBD-based methdologies in exogamic Eucalyptus spp. populations(Crop Breeding and Applied Biotechnology, 2010-12) Rosado, Tatiana Barbosa; Tomaz, Rafael Simões; Ribeiro Junior, Marcio Fernandes; Guimarães, Lúcio Mauro da Silva; Araújo, Elza Fernandes de; Alfenas, Acelino Couto; Cruz, Cosme Damião; Rosado, Antônio MarcosIn Brazil the rust caused by Puccinia psidii Winter stands out as the most important disease of eucalyptus. The use of resistant genotypes is the main control method, which makes the detection of markers linked to rust resistance essential to the selection of resistant genotypes. In this study, an F1 progeny of 131 plants from interspecific crossings of Eucalyptus was used to identify markers linked to resistance genes for this pathogen. An integrated map was constructed for linkage group three based on microsatellite markers. For QTL mapping two methodologies based on alleles identical-by-descent (IBD) were used: single marker analysis of Haseman and Elston and the interval mapping procedure of Fulker and Cardon. Both methods showed significant association for the Embra 125 marker.The QTL that explained 42 % of the phenotypic variation was mapped to 0.02 cM of this marker by the Fulker and Cardon. Marker Embra 125 has potential use in assisted selection, thus increasing the efficiency of the selection of resistant genotypes.Item Joint analysis of phenotypic and molecular diversity provides new insights on the genetic variability of the brazilian physic nut germplasm bank(Genetics and Molecular Biology, 2013-08-16) Bhering, Leonardo Lopes; Alves, Alexandre Alonso; Rosado, Tatiana Barbosa; Laviola, Bruno Galvêas; Formighieri, Eduardo Fernandes; Cruz, Cosme DamiãoThe genetic variability of the Brazilian physic nut (Jatropha curcas) germplasm bank (117 accessions) was assessed using a combination of phenotypic and molecular data. The joint dissimilarity matrix showed moderate correlation with the original matrices of phenotypic and molecular data. However, the correlation between the phenotypic dissimilarity matrix and the genotypic dissimilarity matrix was low. This finding indicated that molecular markers (RAPD and SSR) did not adequately sample the genomic regions that were relevant for phenotypic differentiation of the accessions. The dissimilarity values of the joint dissimilarity matrix were used to measure phenotypic + molecular diversity. This diversity varied from 0 to 1.29 among the 117 accessions, with an average dissimilarity among genotypes of 0.51. Joint analysis of phenotypic and molecular diversity indicated that the genetic diversity of the physic nut germplasm was 156% and 64% higher than the diversity estimated from phenotypic and molecular data, respectively. These results show that Jatropha genetic variability in Brazil is not as limited as previously thought.Item Agrupamento de modelos de regressão da análise de adaptabilidade e estabilidade de genótipos(Pesquisa Agropecuária Brasileira, 2010-11-11) Vasconcelos, Edmar Soares de; Cruz, Cosme Damião; Regazzi, Adair José; Bhering, Leonardo Lopes; Rosado, Tatiana Barbosa; Vasconcelos, Fernando Soares deO objetivo deste trabalho foi evidenciar diferenças entre modelos de regressão, obtidos pelo método de Eberhart & Russell, na análise de adaptabilidade e estabilidade de comportamento de genótipos, e propor uma metodologia de agrupamento dos modelos similares. O teste para verificar a identidade de modelos foi empregado em dados de avaliação de 14 genótipos de milho em oito ambientes. Uma vez rejeitada a hipótese de igualdade dos modelos de regressão, realizou-se o agrupamento desses modelos com base no cálculo do quadrado médio da redução (QMRed) entre pares dos modelos de regressão. Após a obtenção desses valores, foi selecionado o de menor magnitude e verificada sua significância pelo teste F. NA hipótese de esse QMRed não ser significativo, o par de modelos relacionado a ele forma o grupo inicial. O método para verificar a identidade de modelos pode ser usado com sucesso no agrupamento de equações de regressão linear obtidas pelo método de Eberhart & Russell com o objetivo de estudar a adaptabilidade e a estabilidade de genótipos. O método de agrupamento de modelos similares permite formar grupos de genótipos com o mesmo comportamento estatístico.Item Detection and mapping of a lethal locus in a eucalyptus hybrid population(Pesquisa Agropecuária Brasileira, 2011-09-13) Rosado, Tatiana Barbosa; Tomaz, Rafael Simões; Rocha, Rodrigo Barros; Rosado, Antônio Marcos; Alves, Alexandre Alonso; Araújo, Elza Fernandes de; Alfenas, Acelino Couto; Cruz, Cosme DamiãoThe objective of this work was to verify the existence of a lethal locus in a eucalyptus hybrid population, and to quantify the segregation distortion in the linkage group 3 of the Eucalyptus genome. A E. grandis x E. urophylla hybrid population, which segregates for rust resistance, was genotyped with 19 microsatellite markers belonging to linkage group 3 of the Eucalyptus genome. To quantify the segregation distortion, maximum likelihood (ML) models, specific to outbreeding populations, were used. These models consider the observed marker genotypes and the lethal locus viability as parameters. The ML solutions were obtained using the expectation‑maximization algorithm. A lethal locus in the linkage group 3 was verified and mapped, with high confidence, between the microssatellites EMBRA 189 e EMBRA 122. This lethal locus causes an intense gametic selection from the male side. Its map position is 25 cM from the locus which controls the rust resistance in this population.