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Effect of bacterial inoculation, plant genotype and developmental stage on root-associated and endophytic bacterial communities in potato (Solanum tuberosum)

ANDREOTE, Fernando Dini; ROCHA, Ulisses Nunes da; ARAUJO, Welington Luiz; AZEVEDO, Joao Lucio; OVERBEEK, Leonard Simon van
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.08%
Beneficial bacteria interact with plants by colonizing the rhizosphere and roots followed by further spread through the inner tissues, resulting in endophytic colonization. The major factors contributing to these interactions are not always well understood for most bacterial and plant species. It is believed that specific bacterial functions are required for plant colonization, but also from the plant side specific features are needed, such as plant genotype (cultivar) and developmental stage. Via multivariate analysis we present a quantification of the roles of these components on the composition of root-associated and endophytic bacterial communities in potato plants, by weighing the effects of bacterial inoculation, plant genotype and developmental stage. Spontaneous rifampicin resistant mutants of two bacterial endophytes, Paenibacillus sp. strain E119 and Methylobacterium mesophilicum strain SR1.6/6, were introduced into potato plants of three different cultivars (Eersteling, Robijn and Karnico). Densities of both strains in, or attached to potato plants were measured by selective plating, while the effects of bacterial inoculation, plant genotype and developmental stage on the composition of bacterial, Alphaproteobacterial and Paenibacillus species were determined by PCR-denaturing gradient gel-electrophoresis (DGGE). Multivariate analyses revealed that the composition of bacterial communities was mainly driven by cultivar type and plant developmental stage...

Petroleum contamination impact on macrobenthic communities under the influence of an oil refinery: Integrating chemical and biological multivariate data

VENTURINI, Natalia; MUNIZ, Pablo; BICEGO, Marcia C.; MARTINS, Cesar C.; TOMMASI, Luiz Roberto
Fonte: ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD Publicador: ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.08%
Petroleum contamination impact on macrobenthic communities in the northeast portion of Todos os Santos Bay was assessed combining in multivariate analyses, chemical parameters such as aliphatic and polycyclic aromatic hydrocarbon indices and concentration ratios with benthic ecological parameters. Sediment samples were taken in August 2000 with a 0.05 m(2) van Veen grab at 28 sampling locations. The predominance of n-alkanes with more than 24 carbons, together with CPI values close to one, and the fact that most of the stations showed UCM/resolved aliphatic hydrocarbons ratios (UCM:R) higher than two, indicated a high degree of anthropogenic contribution, the presence of terrestrial plant detritus, petroleum products and evidence of chronic oil pollution. The indices used to determine the origin of PAH indicated the occurrence of a petrogenic contribution. A pyrolytic contribution constituted mainly by fossil fuel combustion derived PAH was also observed. The results of the stepwise multiple regression analysis performed with chemical data and benthic ecological descriptors demonstrated that not only total PAH concentrations but also specific concentration ratios or indices such as >= C24:< C24, An/178 and Fl/Fl + Py, are determining the structure of benthic communities within the study area. According to the BIO-ENV results petroleum related variables seemed to have a main influence on macrofauna community structure. The PCA ordination performed with the chemical data resulted in the formation of three groups of stations. The decrease in macrofauna density...

Multivariate analyses of UV-Vis absorption spectral data from cachaca wood extracts: a model to classify aged Brazilian cachacas according to the wood species used

Silva, Alexandre Ataide da; De Keukeleire, Denis; Rodrigues, Daniel Cardoso; Franco, Douglas Wagner
Fonte: ROYAL SOC CHEMISTRY; CAMBRIDGE Publicador: ROYAL SOC CHEMISTRY; CAMBRIDGE
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
45.95%
Multivariate analyses of UV-Vis spectral data from cachaca wood extracts provide a simple and robust model to classify aged Brazilian cachacas according to the wood species used in the maturation barrels. The model is based on inspection of 93 extracts of oak and different Brazilian wood species by a non-aged cachaca used as an extraction solvent. Application of PCA (Principal Components Analysis) and HCA (Hierarchical Cluster Analysis) leads to identification of 6 clusters of cachaca wood extracts (amburana, amendoim, balsamo, castanheira, jatoba, and oak). LDA (Linear Discriminant Analysis) affords classification of 10 different wood species used in the cachaca extracts (amburana, amendoim, balsamo, cabreuva-parda, canela-sassafras, castanheira, jatoba, jequitiba-rosa, louro-canela, and oak) with an accuracy ranging from 80% (amendoim and castanheira) to 100% (balsamo and jequitiba-rosa). The methodology provides a low-cost alternative to methods based on liquid chromatography and mass spectrometry to classify cachacas aged in barrels that are composed of different wood species.; FAPESP; ; CAPES; ; CNPq;

Aplicação de análise multivariada aos dados de análise cromatográfica e espectroscopia para a diferenciação de extratos de madeira; Multivariate analysis applied to chromatography and spectroscopy data to differentiation woods extracts

Silva, Alexandre Ataide da
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/04/2012 PT
Relevância na Pesquisa
45.97%
A presença de 14 compostos fenólicos (ácido elágico, ácido gálico, vanilina, siringaldeído, sinapaldeído, coniferaldeído, ácido vanílico , siríngico ácido, a quercetina, trans-resveratrol, catequina, epicatequina, eugenol, e miricetina) e duas cumarinas (escopoletina e cumarina) foi investigada por HPLC-ESI-MSn em um total de 25 extratos de aguardente de seis diferentes madeiras brasileiras e o carvalho, comumente utilizados pela indústria de tanoaria para o envelhecimento da cachaça. Estes dados foram comparados com os anteriormente obtidos utilizando HPLC-DAD-Fluorescência. Questões pendentes relativas à atribuição da epicatequina, co-eluições do ácido gálico e do ácido elagico respectivamente foram resolvidas utilizando HPLC-ESI-MSn. Além disso, elaborou-se uma impressão digital cromatográfica de HPLC-DAD usando a análise quimiométrica (PCA) com base nos perfis de eluição cromatográfica dos extratos monitorizada a 280 nm. As principais diferenças observadas entre o carvalho e as madeiras brasileiras reside nas concentrações de cumarina, catequina, siringaldeído, e coniferaldeído. A análise quimiometrica do perfil do quantitativo dos 14 compostos fenólicos e das duas cumarinas nos extractos de madeira permitiu uma boa diferenciação entre os extratos das madeiras brasileiras e os extratos de carvalho. A impressão digital cromatográfica analisada por PCA revelou diferenças significativas entre as madeiras brasileiras e o carvalho...

Classification of Aristolochia species based on GC-MS and chemometric analyses of essential oils

Francisco, Carla S.; Messiano, Gisele B.; Lopes, Lucia M. X.; Tininis, Aristeu G.; de Oliveira, Jos E.; Capellari, Lindolpho
Fonte: Pergamon-Elsevier B.V. Ltd Publicador: Pergamon-Elsevier B.V. Ltd
Tipo: Artigo de Revista Científica Formato: 168-175
ENG
Relevância na Pesquisa
45.95%
Essential oils were obtained from roots of 10 Aristolochia species by hydrodistillation and analysed by GC MS. A total of 75 compounds were identified in the analysed oils. Multivariate analyses of the chemical constituents of the roots enabled classification of the species into four morphological groups. These forms of analysis represent an aid in identification of further specimens belonging to these species. (C) 2007 Elsevier Ltd. All rights reserved.

Anatomy of Brazilian Eriocaulaceae: correlation with taxonomy and habitat using multivariate analyses

Scatena, V. L.; Giulietti, A. M.; Borba, E. L.; van den Berg, C.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 1-22
ENG
Relevância na Pesquisa
66.09%
In this study we present a survey on vegetative anatomy in species of Actinocephalus, Blastocaulon, Eriocaulon, Leiothrix, Paepalanthus, Philodice, Syngonanthus, and Tonina (Eriocaulaceae). Multivariate analyses were used to correlate anatomical characters to taxa and the habitats where the species occur. Root and stem anatomical characters seem to be more affected by environmental factors where these species occur, and seem of little value for delimiting major taxonomic groups within the family. Other characters in the leaves, such as epidermis with thickened wall cells, compartmented substomatal chambers, mesophyll with hypodermis, compact chlorenchyma, collenchymatous bundle sheath extensions, and numerous vascular bundles, were shown to be important for defining species clusters in Leiothrix, Syngonanthus, and Paepalanthus subg. Platycaulon. Similarly, loosely aggregated chlorenchyma caused Blastocaulon, Eriocaulon, Philodice, Syngonanthus sect. Carpocephalus, S. sect. Syngonanthus, and Tonina, genera from humid environments, to cluster. Scape characters appear to be more informative in discriminating groups. This situation probably reflects lower selection pressures determining anatomical characters of this organ.

Genetic divergence among maize hybrids by morphological descriptors

Rigon, João Paulo Gonsiorkiewicz; Capuani, Silvia; Rigon, Carlos Alberto Gonsiorkiewicz
Fonte: Instituto Agronômico de Campinas Publicador: Instituto Agronômico de Campinas
Tipo: Artigo de Revista Científica Formato: 156-160
ENG
Relevância na Pesquisa
46.09%
Two experiments with 25 maize commercial hybrids were carried out in a direct sowing system in Southern Brazil in the harvests of 2009/2010 and 2010/2011. Quantitative descriptors were used with the objective of determining the genetic divergence and the relative contributions of traits among hybrids for extraction of inbred lines. This study was carried out in Oxisol soil using a randomized block design with four replicates. Data were subjected to combined analysis of variance, and based on the multivariate analyses, Tocher and average linkage (UPGMA) cluster analyses, based on generalized distance of Mahalanobis, to quantify divergence in addition to Singh criterion to validate trait with the most contribution. The multivariate methods were consistent with each other, and the weight of 100 grains was the trait that contributed most to the divergence and had similar behavior in grain yield between hybrids in both years. Furthermore, this descriptor representing significant genetic variability for crossings and lines extraction to hybridization between BM 3061, ATL 200 and P 30B39 Y.

Multivariate analyses of genotype x environment interaction of popcorn

Miranda,Glauco Vieira; Souza,Leandro Vagno de; Guimarães,Lauro José Moreira; Namorato,Heraldo; Oliveira,Lucimar Rodrigues; Soares,Marcelo Oliveira
Fonte: Embrapa Informação Tecnológica; Pesquisa Agropecuária Brasileira Publicador: Embrapa Informação Tecnológica; Pesquisa Agropecuária Brasileira
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 EN
Relevância na Pesquisa
46.03%
The objectives of this work were to evaluate the genotype x environment (GxE) interaction for popcorn and to compare two multivariate analyses methods. Nine popcorn cultivars were sown on four dates one month apart during each of the agricultural years 1998/1999 and 1999/2000. The experiments were carried out using randomized block designs, with four replicates. The cv. Zélia contributed the least to the GxE interaction. The cv. Viçosa performed similarly to cv. Rosa-claro. Optimization of GxE was obtained for cv. CMS 42 for a favorable mega-environment, and for cv. CMS 43 for an unfavorable environment. Multivariate analysis supported the results from the method of Eberhart & Russell. The graphic analysis of the Additive Main effects and Multiplicative Interaction (AMMI) model was simple, allowing conclusions to be made about stability, genotypic performance, genetic divergence between cultivars, and the environments that optimize cultivar performance. The graphic analysis of the Genotype main effects and Genotype x Environment interaction (GGE) method added to AMMI information on environmental stratification, defining mega-environments and the cultivars that optimized performance in those mega-environments. Both methods are adequate to explain the genotype x environment interactions.

Influence of environmental variation on Atlantic Forest tree-shrub-layer phytogeography in southeast Brazil

Nettesheim,Felipe Cito; Menezes,Luis Fernando Tavares de; Carvalho,Daniel Costa de; Conde,Marilena Menezes Silva; Araujo,Dorothy Sue Dunn de
Fonte: Sociedade Botânica do Brasil Publicador: Sociedade Botânica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2010 EN
Relevância na Pesquisa
46.09%
This work assessed data from 32 forest sites in Rio de Janeiro and São Paulo, Brazil, using multivariate analysis to answer the question: Are there floristic patterns of the Atlantic Forest tree-shrub layer related to the Serra do Mar and the width of coastal plains in the states of Rio de Janeiro and São Paulo? Three multivariate analyses were performed to investigate the relationship between the tree-shrub flora and environmental variation in these 32 study areas. Our analyses demonstrated the influence of geo-climatic variation on floristic differentiation of tree and shrub species in Atlantic Forest regions generating groups of areas based on similar biotic and abiotic characteristics. These groups support the existence of floristic patterns within the states of São Paulo and Rio de Janeiro and reflect tree-shrub species substitution between the study areas as a consequence of annual rainfall, altitude, and mean annual temperature variation linked to a change in the position of the Serra do Mar and an increase in coastal plain width. Preferential species were cited for each group and should be considered in restoration and conservation programs for the phytoecological regions represented by the groups.

Multivariate analyses of factors associated with unemployment in people with multiple sclerosis.

Grønning, M; Hannisdal, E; Mellgren, S I
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1990 EN
Relevância na Pesquisa
46.09%
Variables at onset of multiple sclerosis (MS) as predictors of time to unemployment have been studied using multivariate survival (time-to-response) analyses. The study consisted of 79 patients with MS diagnosed in the two most northern counties of Norway between 1974-82. Diagnostic category, age at onset, sex, county, symptom groups, course of disease and occupation groups were identified as possible prognostic variables. Forty one patients (51%) were unemployed at last follow up. None of the 15 patients with probable or possible MS were unemployed due to MS. The multivariate analyses selected the nonremittent course or heavy physical work and age over 30 at onset as high risk factors associated with early unemployment.

Phylogenetic and Multivariate Analyses To Determine the Effects of Different Tillage and Residue Management Practices on Soil Bacterial Communities▿ †

Ceja-Navarro, Javier A.; Rivera-Orduña, Flor N.; Patiño-Zúñiga, Leonardo; Vila-Sanjurjo, Antón; Crossa, José; Govaerts, Bram; Dendooven, Luc
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.03%
Bacterial communities are important not only in the cycling of organic compounds but also in maintaining ecosystems. Specific bacterial groups can be affected as a result of changes in environmental conditions caused by human activities, such as agricultural practices. The aim of this study was to analyze the effects of different forms of tillage and residue management on soil bacterial communities by using phylogenetic and multivariate analyses. Treatments involving zero tillage (ZT) and conventional tillage (CT) with their respective combinations of residue management, i.e., removed residue (−R) and kept residue (+R), and maize/wheat rotation, were selected from a long-term field trial started in 1991. Analysis of bacterial diversity showed that soils under zero tillage and crop residue retention (ZT/+R) had the highest levels of diversity and richness. Multivariate analysis showed that beneficial bacterial groups such as fluorescent Pseudomonas spp. and Burkholderiales were favored by residue retention (ZT/+R and CT/+R) and negatively affected by residue removal (ZT/−R). Zero-tillage treatments (ZT/+R and ZT/−R) had a positive effect on the Rhizobiales group, with its main representatives related to Methylosinus spp. known as methane-oxidizing bacteria. It can be concluded that practices that include reduced tillage and crop residue retention can be adopted as safer agricultural practices to preserve and improve the diversity of soil bacterial communities.

Assessment of the Disposition of Chiral Polychlorinated Biphenyls in Female mdr 1a/b Knockout versus Wild-type Mice Using Multivariate Analyses

Milanowski, Bartłomiej; Lulek, Janina; Lehmler, Hans-Joachim; Kania-Korwel, Izabela
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.03%
Polychlorinated biphenyls (PCBs) are present in the environment as complex mixtures, which make it challenging to identify PCB congeners that may be subject to active transport processes. Here we employ a transgenic mouse model in combination with multivariate analyses to investigate if chiral PCBs 91, 95, 132, 136, 149, 174, 176 and 183 are subject to active (enantioselective) transport by multidrug resistance (MDR) transporters. A synthetic PCB mixture containing these congeners was administered orally to female FVB or mdr1a/1b knockout mice. Due to the short half-life of chiral PCB congeners, mice were euthanized after 24 hours and PCB concentrations and enantiomeric fractions were determined in selected tissues and excreta. Principal component analysis did not reveal differences between wild-type and mdr1a/1b knockout mice. However, Hotelling T2-test revealed significantly lower PCB concentrations and a more pronounced enantiomeric enrichment in the adipose tissue of mdr1a/1b knockout mice. These differences are due to higher body weights and higher fecal fat contents of mdr1a/1b knockout mice. Analysis of the enantiomeric fractions of PCBs 91, 95, 136, 149 and 174 showed a significant enantiomeric enrichment for all five congeners in wild-type and mdr1a/1b knockout mice. Overall...

Diagnosis of Alzheimer’s Disease Using Neuropsychological Testing Improved by Multivariate Analyses

Chapman, Robert M.; Mapstone, Mark; Porsteinsson, Anton P.; Gardner, Margaret N.; McCrary, John W.; DeGrush, Elizabeth; Reilly, Lindsey A.; Sandoval, Tiffany C.; Guillily, Maria D.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/2010 EN
Relevância na Pesquisa
46.03%
Neuropsychological assessment aids in the diagnosis of Alzheimer’s disease (AD) by objectively establishing cognitive impairment from standardized tests. We present new criteria for diagnosis that use weighted combined scores from multiple tests. Our method employs two multivariate analyses: Principal Components Analysis (PCA) and discriminant analysis. PCA (N = 216 subjects) created more interpretable cognitive dimensions by resolving 49 test measures in our neuropsychological battery to 13 component scores for each subject. The component scores were used to build discriminant functions that classified each participant as either an early-stage AD (N = 55) or normal elderly (N = 78). Our discriminant function performed with high accuracy, sensitivity, and specificity (nearly all >90%) in the development, a cross-validation, and a new subjects validation. When contrasted to two different traditional empirical methods for diagnosis (using cutscores and defining AD as falling below 5% on two or more test domains), our results suggested that the multivariate method was superior in classification (approximately 20% more accurate).

Multivariate analyses reveal common and drug specific genetic influences on responses to four drugs of abuse

Belknap, John K.; Metten, Pamela; Beckley, Ethan H.; Crabbe, John C.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.01%
Vulnerability to abused drugs is influenced by multiple genes unique to each drug as well as to risk genes for polydrug abuse. If several inbred mouse strains respond to different drugs similarly, this implies the action of a common group of genes. Simultaneous analysis of multiple responses to multiple drugs has been attempted infrequently. We performed multivariate analyses of published strain responses to four drugs. Genetic similarity in responses did not simply track pharmacological class. Withdrawal severity and preference for ethanol and diazepam were affected by many genes in common, although inversely. We focused on behavioral responses, but there is a growing archival data base of physiological, pharmacological and biochemical strain traits. The genomics community is increasingly focusing on single nucleotide polymorphism (SNP) and haplotype-based gene mapping approaches, for which inbred strain data are also useful. Thus, similar analyses should be applicable to other laboratories, traits, and genotypes.

Affymetrix GeneChip microarray preprocessing for multivariate analyses

McCall, Matthew N; Almudevar, Anthony
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.12%
Affymetrix GeneChip microarrays are the most widely used high-throughput technology to measure gene expression, and a wide variety of preprocessing methods have been developed to transform probe intensities reported by a microarray scanner into gene expression estimates. There have been numerous comparisons of these preprocessing methods, focusing on the most common analyses—detection of differential expression and gene or sample clustering. Recently, more complex multivariate analyses, such as gene co-expression, differential co-expression, gene set analysis and network modeling, are becoming more common; however, the same preprocessing methods are typically applied. In this article, we examine the effect of preprocessing methods on some of these multivariate analyses and provide guidance to the user as to which methods are most appropriate.

A review of multivariate analyses in imaging genetics

Liu, Jingyu; Calhoun, Vince D.
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 26/03/2014 EN
Relevância na Pesquisa
46.21%
Recent advances in neuroimaging technology and molecular genetics provide the unique opportunity to investigate genetic influence on the variation of brain attributes. Since the year 2000, when the initial publication on brain imaging and genetics was released, imaging genetics has been a rapidly growing research approach with increasing publications every year. Several reviews have been offered to the research community focusing on various study designs. In addition to study design, analytic tools and their proper implementation are also critical to the success of a study. In this review, we survey recent publications using data from neuroimaging and genetics, focusing on methods capturing multivariate effects accommodating the large number of variables from both imaging data and genetic data. We group the analyses of genetic or genomic data into either a priori driven or data driven approach, including gene-set enrichment analysis, multifactor dimensionality reduction, principal component analysis, independent component analysis (ICA), and clustering. For the analyses of imaging data, ICA and extensions of ICA are the most widely used multivariate methods. Given detailed reviews of multivariate analyses of imaging data available elsewhere...

The Decoding Toolbox (TDT): a versatile software package for multivariate analyses of functional imaging data

Hebart, Martin N.; Görgen, Kai; Haynes, John-Dylan
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 06/01/2015 EN
Relevância na Pesquisa
46.21%
The multivariate analysis of brain signals has recently sparked a great amount of interest, yet accessible and versatile tools to carry out decoding analyses are scarce. Here we introduce The Decoding Toolbox (TDT) which represents a user-friendly, powerful and flexible package for multivariate analysis of functional brain imaging data. TDT is written in Matlab and equipped with an interface to the widely used brain data analysis package SPM. The toolbox allows running fast whole-brain analyses, region-of-interest analyses and searchlight analyses, using machine learning classifiers, pattern correlation analysis, or representational similarity analysis. It offers automatic creation and visualization of diverse cross-validation schemes, feature scaling, nested parameter selection, a variety of feature selection methods, multiclass capabilities, and pattern reconstruction from classifier weights. While basic users can implement a generic analysis in one line of code, advanced users can extend the toolbox to their needs or exploit the structure to combine it with external high-performance classification toolboxes. The toolbox comes with an example data set which can be used to try out the various analysis methods. Taken together, TDT offers a promising option for researchers who want to employ multivariate analyses of brain activity patterns.

Multivariate analyses of genotype x environment interaction of popcorn.

MIRANDA, G.V.; SOUZA, L.V. de; GUIMARÃES, L.J.M.; NAMORATO, H.; OLIVEIRA, L.R.; SOARES, M.O.
Fonte: Pesquisa Agropecuária Brasileira, Brasília, v.44, n. 1, p. 45-50, jan. 2009. Publicador: Pesquisa Agropecuária Brasileira, Brasília, v.44, n. 1, p. 45-50, jan. 2009.
Tipo: Artigo em periódico indexado (ALICE)
EN
Relevância na Pesquisa
46.03%
The objectives of this work were to evaluate the genotype x environment (GxE) interaction for popcorn and to compare two multivariate analyses methods. Nine popcorn cultivars were sown on four dates one month apart during each of the agricultural years 1998/1999 and 1999/2000. The experiments were carried out using randomized block designs, with four replicates. The cv. Zélia contributed the least to the GxE interaction. The cv. Viçosa performed similarly to cv. Rosa-claro. Optimization of GxE was obtained for cv. CMS 42 for a favorable mega-environment, and for cv. CMS 43 for an unfavorable environment. Multivariate analysis supported the results from the method of Eberhart & Russell. The graphic analysis of the Additive Main effects and Multiplicative Interaction (AMMI) model was simple, allowing conclusions to be made about stability, genotypic performance, genetic divergence between cultivars, and the environments that optimize cultivar performance. The graphic analysis of the Genotype main effects and Genotype x Environment interaction (GGE) method added to AMMI information on environmental stratification, defining mega-environments and the cultivars that optimized performance in those mega-environments. Both methods are adequate to explain the genotype x environment interactions.; 2009

Genetic divergence among maize hybrids by morphological descriptors

Rigon,João Paulo Gonsiorkiewicz; Capuani,Silvia; Rigon,Carlos Alberto Gonsiorkiewicz
Fonte: Instituto Agronômico de Campinas Publicador: Instituto Agronômico de Campinas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2015 EN
Relevância na Pesquisa
46.09%
Two experiments with 25 maize commercial hybrids were carried out in a direct sowing system in Southern Brazil in the harvests of 2009/2010 and 2010/2011. Quantitative descriptors were used with the objective of determining the genetic divergence and the relative contributions of traits among hybrids for extraction of inbred lines. This study was carried out in Oxisol soil using a randomized block design with four replicates. Data were subjected to combined analysis of variance, and based on the multivariate analyses, Tocher and average linkage (UPGMA) cluster analyses, based on generalized distance of Mahalanobis, to quantify divergence in addition to Singh criterion to validate trait with the most contribution. The multivariate methods were consistent with each other, and the weight of 100 grains was the trait that contributed most to the divergence and had similar behavior in grain yield between hybrids in both years. Furthermore, this descriptor representing significant genetic variability for crossings and lines extraction to hybridization between BM 3061, ATL 200 and P 30B39 Y.

Conceptual and statistical problems associated with the use of diversity indices in ecology

Barrantes,Gilbert; Sandoval,Luis
Fonte: Revista de Biología Tropical Publicador: Revista de Biología Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2009 EN
Relevância na Pesquisa
46.12%
Diversity indices, particularly the Shannon-Wiener index, have extensively been used in analyzing patterns of diversity at different geographic and ecological scales. These indices have serious conceptual and statistical problems which make comparisons of species richness or species abundances across communities nearly impossible. There is often no a single statistical method that retains all information needed to answer even a simple question. However, multivariate analyses could be used instead of diversity indices, such as cluster analyses or multiple regressions. More complex multivariate analyses, such as Canonical Correspondence Analysis, provide very valuable information on environmental variables associated to the presence and abundance of the species in a community. in addition, particular hypotheses associated to changes in species richness across localities, or change in abundance of one, or a group of species can be tested using univariate, bivariate, and/or rarefaction statistical tests. The rarefaction method has proved to be robust to standardize all samples to a common size. Even the simplest method as reporting the number of species per taxonomic category possibly provides more information than a diversity index value. Rev. Biol. Trop. 57 (3): 451-460. Epub 2009 September 30.