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Search Results: 1 - 10 of 177174 matches for " Giselle Mariano Lessa de;Albuquerque "
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Estima??o de parametros genéticos em caprinos leiteiros por meio de análise de regress?o aleatória utilizando-se a Amostragem de Gibbs
Assis, Giselle Mariano Lessa de;Albuquerque, Lucia Galv?o de;Sarmento, José Lindenberg Rocha;Carneiro Júnior, José Marques;Lopes, Paulo Sávio;Rodrigues, Marcelo Teixeira;
Revista Brasileira de Zootecnia , 2006, DOI: 10.1590/S1516-35982006000300011
Abstract: random regression models were used to estimate genetic parameters for test-day milk yield (pldc) of alpine dairy goats, implemented by bayesian methods with gibbs sampling. the estimates were compared with those obtained by random regression analysis, using reml. heritability estimates obtained by bayesian analysis ranged from 0.18 to 0.37, while those obtained by reml ranged from 0.09 to 0.32. genetic correlations between yields of close test days approached the unit, but decreased gradually as the interval between test days increased. results indicated that random regression models are appropriate to model the covariance structure of pldc and to predict genetic gains and select animals along the lactation trajectory of dairy goats. results obtained by bayesian and reml approaches were similar, although genetic variance and heritability estimates were slightly higher with bayesian methods.
Aspectos vegetativos de combina??es copa/porta-enxerto em maracujazeiro
Roncatto, Givanildo;Assis, Giselle Mariano Lessa de;Oliveira, Tadário Kamel de;Lessa, Lauro Saraiva;
Revista Brasileira de Fruticultura , 2011, DOI: 10.1590/S0100-29452011000300013
Abstract: the passion fruit plant has stood out among the main fruit tree of the country, however, its life has been reduced mainly due to damage caused by root diseases, and the graft with native species and disease-resistant can solve the problem. so this research aimed to evaluate the grafted vegetative performance of scion varieties and rootstock species combinations of passion fruit plant. the study was developed in screenhouse (50% shaded) at acre embrapa, rio branco, between september and december in 2007. the seven varieties studied were the yellow passion fruit 'fb 100' and 'fb 200' from flora brazil (araguari, mg) nursery, ufac 07, 25, 38, 64 and 70 (universidade federal do acre, rio branco-ac), and the rootstocks were passiflora edulis f. flavicarpa (cuiabá-mt), p. alata, p. edulis and p. quadrangularis (guiratinga-mt), p. serrato-digitata (iac-campinas/sp). the experimental design was randomized blocks, with 12 repetitions. the treatments were 35 combinations scion/rootstock consisting of 5 rootstocks combined with 7 scions. the grafting method used was the cleft at the top hypocotyledonary, and the rootstocks had the following characteristics: three true leaves and seedling height variable (6 to 8 cm), 30 to 90 days after sowing. during the research, the height of the plants, their diameter, the numbers of leaves and internodes as value of the plant development were evaluated. the best vegetative development combinations for the diameter and number of internodes were 'fb 100' and 'fb 200' on p. edulis and p. alata, ufac 07 on p. serrato-digitata, and p. quadrangularis ufac 38 on p.edulis. but the best vegetative development combinations for the height of the plants and number of leaves were fb 100 and fb 200 on p. edulis and p. alata as well as, fb 100 and fb 200 on p. serrato-digitata, ufac 38 on p. alata for plants diameter and number of leaves.
Pegamento da enxertia em diferentes combina??es de variedades e espécies utilizadas como copa e como porta-enxertos de maracujazeiro
Roncatto, Givanildo;Assis, Giselle Mariano Lessa de;Oliveira, Tadário Kamel de;Lessa, Lauro Saraiva;
Revista Brasileira de Fruticultura , 2011, DOI: 10.1590/S0100-29452011005000082
Abstract: brazil is the largest producer of passion fruit. but, in spite of its prominent position, life of passion fruit plant has been reduced mainly due to damage caused by root diseases. as grafting with native species is resistant to diseases, presenting an alternative of production, this research aimed to evaluate the success of grafting in the combinations of scion varieties and species of rootstocks of passion fruit plant. the study was conducted in screenhouse (50% shaded) at acre embrapa, rio branco, between september and december in 2007. the scion variety used for all treatments was the yellow passion fruit 'fb 100' and 'fb 200' from flora brazil (araguari, mg) nursery and 5 other regional varieties (ufac, universidade federal do acre, rio branco-ac) and the rootstocks were passiflora edulis (yellow passion fruit) (cuiabá-mt), p. alata, p. edulis (purple passion fruit) and p. quadrangularis (guiratinga-mt), p. serrato-digitata (iac-campinas/sp). the seeds were previously soaked in distilled water for about 24 h and then sown in plastic tubes (25x5cm) with plantmax@. the cleft at the top hypocotyledonary was the grafting method used, and the rootstocks had the following characteristics: three true leaves and seedling height variable (6 to 8 cm), 30 to 90 days after sowing. seedlings were decapitated up to cotyledons with steel blade, which has been dipped in bleach to 70% each grafting performed. the grafts were obtained from whole seedlings, about 10 cm long, making it the toilet of the leaves. the combination of better performance in relation to the living grafts were ufac 07 on p. edulis (purple passion fruit) and p. alata, ufac 38 on p. edulis (yellow passion fruit), p. edulis (purple passion fruit) and p. alata, ufac 64 on p. serrato-digitata, with 100% of grafting success, while the combination of fb 100 on p. alata had the worst performance, with low rate of success, not reaching 30%.
Predi o de valores genéticos utilizando inferência bayesiana e frequentista em dados simulados = Prediction of genetic values using bayesian inference and frequent on simulated data
José Marques Carneiro Júnior,Giselle Mariano Lessa de Assis,Ricardo Frederico Euclydes,Williane Maria de Oliveira Martins
Acta Scientiarum : Animal Sciences , 2010,
Abstract: Dados simulados foram utilizados para comparar as metodologias Eblup eBayesiana, em dados com homogeneidade de variancias, heterogeneidade de variancia genética e heterogeneidade de variancia genética e ambiental. Para obten o dessas estruturas foram feitos descartes estratégicos dos valores genéticos aditivos e ambientais de acordo com o tipo de heterogeneidade e o nível de variabilidade desejada (alta, média ou baixa), sendo utilizados dois tamanhos de popula o (grande e pequena). Para a metodologia Bayesiana foram utilizados três níveis de informa o a priori: n o informativo, pouco informativo e informativo. A presen a da heterogeneidade de variancias causa problemas para a sele o dos melhores indivíduos, principalmente se a heterogeneidade estiver nos componentes de variancia genética e ambiental, sendo os animais selecionadosequivocadamente do ambiente mais variável. Os métodos comparados tiveram resultados semelhantes, quando distribui es a priori n o informativas foram utilizadas, e as popula es de tamanho grande, de modo geral, apresentaram melhores predi es de valores genéticos.Foi observado, para a metodologia Bayesiana, que o aumento no nível de informa o a priori influencia positivamente as predi es dos valores genéticos, principalmente para as popula es pequenas. O método Bayesiano é indicado para popula es de tamanho pequeno quando há disponibilidade de distribui es a priori informativas. Simulated data were used to compare EBLUP and Bayesian methods in datawith homogeneity of variance, heterogeneity of variance and genetic heterogeneity of genetic and environmental variance. For these structures were strategic disposal of additive genetic and environmental values in accordance with the type of heterogeneity and the desired level of variability: high, medium or low. We used two sizes of population: large and small. For the Bayesian methodology was used three levels of a priori information: no information, justinformation and informative. For verification of the introduction of different levels of information they were used the mistake percentage in relation to the true value of the variance components the Spearman correlation and the medium square of the mistake among the real genetic values and predicted them. The presence of heterogeneity of variances cause problems for the selection of the best individuals, especially if the heterogeneity is present in the components of genetic variance and environmental and animals are mistakenly selected the more variable environment. The methods presented similar results when compared not
Estimation of variances of the effects of incomplete diallels using a matrix approach
Assis, Giselle Mariano Lessa de;Fonseca, Ricardo da;Cruz, Cosme Dami?o;Carneiro Júnior, José Marques;
Genetics and Molecular Biology , 2004, DOI: 10.1590/S1415-47572004000300017
Abstract: a matrix approach is described for assessing the variance of effects in incomplete diallels designs. the method is illustrated by reference to simulated complete and incomplete diallels using different combinations of constraints, average degree of dominance and, for the incomplete diallel, number of hybrids. our results showed that caution should be taken in working with incomplete diallels under conditions of overdominance because there were changes in the rank of the genotypes when the excluded hybrid had parents with a low frequency of the favorable allele (i.e. the allele which increases expression of a character). the expression described in this paper is a rapid and safe approach to estimate variances and covariances of the effects of contrasts of incomplete diallels.
Influência da informa??o a priori na avalia??o genética animal utilizando dados simulados
Carneiro Júnior, José Marques;Assis, Giselle Mariano Lessa de;Euclydes, Ricardo Frederico;Lopes, Paulo Sávio;
Revista Brasileira de Zootecnia , 2005, DOI: 10.1590/S1516-35982005000600014
Abstract: the influence of a priori information on animal genetic evaluation was studied using a simulated 3.000 centimorgans genome, for a single trait governed by 800 loci, with two alleles for locus, and heritability varying from 0.40 to 0.60. three populations with different sizes were derived from the base-population constituted by 1.500 males and 1.500 females: pop1 (100 animals), pop2 (300 animals) and pop3 (1.600 animals). three a priori information levels were considered: no-informative priors (pni), slightly informative priors (ppi) and informative priors (pi). the effect of using overestimated priors (with 50% error), considering slightly informative and informative priors on genetic evaluation was also studied. the influence of different levels of prior information on genetic evaluation was evaluated by the following criteria: error percentage related to the true value of variance components, spearman correlation and mean square error between real and predicted genetic values. pop1 and pop2 presented larger error percentages and were more sensitive to prior information. larger levels of information led to best variance estimates and qme became smaller by increasing the information level, mainly for small populations. however, spearman correlation were lower than 0.70 for pop1 and pop2, indicating significant changes in ranking of animals. therefore, genetic evaluation of small populations is problematic, even if additional prior information is available.
Genetic divergence among accessions of Arachis repens based on vegetative morphological traits
Azevedo, José Marlo Araújo de;Silva, Hellen Sandra Freires da;Assis, Giselle Mariano Lessa de;Santos, Laís Fernanda Andrade dos;Wolter, Priscila Ferreira;
Revista Brasileira de Zootecnia , 2011, DOI: 10.1590/S1516-35982011001000001
Abstract: the objective of this study was to verify the existence of genetic variability among accessions of arachis repens based on vegetative morphological characters, identifying those which contribute least for distinction of those accessions. nineteen accessions were evaluated in a completely randomized design with ten replicates, established in 4-m2 plots. the traits evaluated were: basal leaflet length, basal leaflet width, apical leaflet length, apical leaflet width, petiole length, internode average length and internode diameter. the data obtained were submitted to univariate statistical analysis and accessions were grouped by the scott-knott test, at 1% of probability. the analysis of canonical variables and tocher method were used to study the genetic divergence among accessions. six heterogeneous groups were formed by tocher method and eight groups were formed by technique of canonical variables, in which a consistency among grouping set by the different techniques used was observed. there is genetic divergence among accessions of a. repens on the basis of vegetative morphology traits, but there is the need to extend variability in banco ativo de germoplasma de amendoim forrageiro (active germplasm bank of forage peanut). apical leaflet length is the trait that contributes least to the accessions' distinctions, but it is important to maintain the standard cluster, and it should not be discarded
Sele??o de genótipos de amendoim forrageiro para cobertura do solo e produ??o de biomassa aérea no período de estabelecimento utilizando-se metodologia de modelos mistos
Assis, Giselle Mariano Lessa de;Valentim, Judson Ferreira;Carneiro Júnior, José Marques;Azevedo, José Marlo Araújo de;Ferreira, Aliedson Sampaio;
Revista Brasileira de Zootecnia , 2008, DOI: 10.1590/S1516-35982008001100001
Abstract: this study aimed to estimate genetic parameters and to select genotypes of forage peanut with greater ground cover and aerial biomass production during establishment period in the environmental conditions of acre. the experiment was planted in december/2005, in a randomized block with four repetitions. twenty one genotypes of forage peanut were evaluated, including three cultivars: amarillo, alqueire 1, and belmonte. genotype selection was based on ground cover and dry matter production. the ground cover evaluations took place between january and october 2006, at intervals of approximately four weeks. the dry matter production was measured 304 days after planting. the variance components were estimated by restricted maximum likelihood method (reml) and genotypic values were predicted by best linear unbiased prediction (blup), according the methodology of mixed models. presence of genetic variability was verified for both traits. individual heritabilities in the wide sense were of medium magnitude, presenting values of 0.36 to 0.58 for the traits ground cover and dry matter production, respectively. the largest variability among genotypes for ground cover occurred between the 12th and 16th week after planting, indicating that this interval is the most appropriate to select genotypes that cover the ground more quickly. genotypic values for dry matter production ranged from 1,609 to 4,132 kg/ha for genotypes bra 015083 and bra 040550, respectively. the genotypes selected for greater ground cover and aerial biomass production during establishment period were belmonte, amarillo, bra 040550, bra 039187, alqueire 1, bra 039799 and bra 035033.
Estima??o de componentes de variancia utilizando-se inferência Bayesiana e freqüentista em dados simulados sob heterogeneidade de variancias
Carneiro Júnior, José Marques;Assis, Giselle Mariano Lessa de;Euclydes, Ricardo Frederico;Torres, Robledo de Almeida;Lopes, Paulo Sávio;
Revista Brasileira de Zootecnia , 2007, DOI: 10.1590/S1516-35982007000700012
Abstract: a genome of 3.000 centimorgans was simulated for a single quantitative trait governed by 800 loci with two alleles per locus. according to the genomic structure proposed, 1,500 males and 1,500 females constituted the base population which was used to form two (small and large) initial populations. two types (only additive genetic variance and both additive genetic and environmental variances) and three variability levels (high, medium and low) of heterogeneity of variances were inserted in the initial populations. variance components were estimated by bayesian inference via gibbs sampling using three different levels of priors (non-informative, slightly informative and informative) and by reml. the best estimates of variance components were obtained with large populations. in small populations, the individual analyses for different variability levels presented problems related to variance components estimation due the small size of subpopulations. both methods presented similar results for variance components when non-informative priors were used in bayesian inference. increasing the level of a priori information improved the estimates of variance components by bayesian inference, especially in small populations.
Estima??o de componentes de variancia sob influência de genes de efeito principal, comparando-se metodologias Bayesiana e clássica sob diferentes cenários
Assis, Giselle Mariano Lessa de;Carneiro Júnior, José Marques;Euclydes, Ricardo Frederico;Torres, Robledo de Almeida;Lopes, Paulo Sávio;
Revista Brasileira de Zootecnia , 2007, DOI: 10.1590/S1516-35982007000600007
Abstract: this study aimed to evaluate the effects of major genes and population size on variance components estimation using four different types of selected populations. variance components were estimated by classical and bayesian methodologies, with three a priori information levels. in general, results from reml and bayesian analyses with flat priors were similar. except for bayesian analysis with an informative prior, additive genetic variance estimates were not accurate in populations in which the trait is controlled by major genes. the use of pedigree information and records of all individuals back to the base-population was necessary to improve accuracy of variance component estimates, except for large populations in which the trait is controlled by a large number of genes.
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