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Age-age correlation for early selection of rubber tree genotypes in São Paulo State, Brazil Genet. Mol. Biol.
Gonçalves,Paulo de Souza; Bortoletto,Nelson; Cardinal,Átila Bento Beleti; Gouvêa,Lígia Regina Lima; Costa,Reginaldo Brito da; Moraes,Mário Luiz Teixeira de.
In a field trial involving 68 rubber tree (Hevea spp.) clones calculation of genotypic correlation coefficients revealed significant age-age correlation from age 1 to 6 (immature period) for girth A and for age 7 to 12 (mature period) for girth B and for age 7 to 12 (production of latex) for yield. Rank correlation coefficients between all immature ages of girth (girth A), all ages of mature girth (girth B) and all annual rubber production (yield) were significant for the three traits, with the coefficients decreasing with increasing age. Selection of the sets of best 30, 15, 10 and 5 clones from the available 68 clones at a given age was generally accompanied by a descending order of percentage success. It was suggested: (a) to have the best 30 clones of...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Hevea brasiliensis; Early clonal multiplication; Genetic correlation; Rank correlation; Evaluation of clones.
Ano: 2005 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572005000500018
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Confidence intervals for rank statistics: Somers' D and extensions AgEcon
Newson, Roger.
Somers’ D is an asymmetric measure of association between two variables, which plays a central role as a parameter behind rank or nonparametric statistical methods. Given predictor variable X and outcome variable Y , we may estimate DYX as a measure of the effect of X on Y , or we may estimate DXY as a performance indicator of X as a predictor of Y. The somersd package allows the estimation of Somers’ D and Kendall’s τα with confidence limits as well as p-values. The Stata 9 version of somersd can estimate extended versions of Somers’ D not previously available, including the Gini index, the parameter tested by the sign test, and extensions to left- or right-censored data. It can also estimate stratified versions of Somers’ D, restricted to pairs in the...
Tipo: Journal Article Palavras-chave: Somersd; Somers' D; Kendall's τ_a; Harrell's c; ROC area; Gini index; Population-attributable risk; Rank correlation; Rank-sum test; Wilcoxon test; Sign test; Confidence intervals; Nonparametric methods; Propensity score; Research Methods/ Statistical Methods.
Ano: 2006 URL: http://purl.umn.edu/117583
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Evaluating early selection in perennial tropical forages. Repositório Alice
FIGUEIREDO, U. J. de; BERCHEMBROCK, Y. V.; VALLE, C. B. do; BARRIOS, S. C. L.; QUESENBERRY, K. H.; MUÑOZ, P. R.; NUNES, J. A. R..
Perennial grass hybrids of Urochloa are evaluated for at least two years during the screening stage trials (SS) and advanced trials (AD) in breeding programs, an expensive and time-consuming process. In this study, we aimed to evaluate the potential for early selection of cultivars in this breeding scheme. We used multiple measurements of agronomic and nutritive value traits of Urochloa humidicola and Urochloa decumbens in the SS, and Urochloa ssp. in the AD. Repeatability coefficient, genetic correlation, selection efficiency (SE), and Spearman correlations were estimated. The results indicated that reliable early selection could be applied, decreasing the evaluation period to one year and a half for SS, and to one year for AD. These results were...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Urochloa spp; Repeatability coefficient; Forage breeding; Rank correlation.
Ano: 2019 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1117770
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Genetic evaluation for persistency of lactation in Holstein cows using a random regression model Genet. Mol. Biol.
Cobuci,Jaime Araujo; Euclydes,Ricardo Frederico; Costa,Claudio Napolis; Torres,Robledo de Almeida; Lopes,Paulo Sávio; Pereira,Carmen Silva.
A model for analyzing test day records including both fixed and random coefficients was applied to the genetic evaluation of first lactation data for Holstein cows. Data comprising 87045 test-day milk yield records from calving between 1997 and 2001 from Holstein herds in 10 regions of the Brazilian state of Minas Gerais. Six persistency of lactation measures were evaluated using breeding values obtained by random regression analyses. The Wilmink function was used to model the additive genetic and permanent environmental effects. Residual variance was constant throughout lactation. Ranking for animals did not change among criteria for persistency measurements, but ranking changes were observed when the estimated breeding value (EBV) for persistency of...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Genetic evaluation; Persistency of lactation; Rank correlation; Random regression models.
Ano: 2007 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000300009
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Genomic simulation for the study of data transformation efficiency in the genetic evaluation of cattle in the presence of heterogeneity - 10.4025/actascianimsci.v34i1.10664 Animal Sciences
Carneiro, Antonio Policarpo Souza; UFV; Carneiro, Paulo Luiz Souza; UESB; Euclydes, Ricardo Frederico; UFV; Martins Filho, Sebastião; UFV; Silva, Fabyano Fonseca; UFV; Cecon, Paulo Roberto; UFV.
Efficiency of data transformation strategies is evaluated to correct heterogeneity among cattle in the genetic evaluation of bulls, cows and progenies. Four data structures of bovine weaning weights were simulated: herds with and without heterogeneity for means and variances, and herds with and without genetic connectedness. In the genetic evaluations, data were used in the original scale and transformed (Logarithmic, Square root, standardization and ratio by phenotypic standard deviation). The evaluated data transformation strategies were not efficient in eliminating the negative effects of heterogeneity among cattle in the genetic evaluation of bulls, cows and progenies.
Palavras-chave: 5.04.02.00-5 genetic connectedness; Rank correlation; Genesys; Scale transformation.
Ano: 2011 URL: http://periodicos.uem.br/ojs/index.php/ActaSciAnimSci/article/view/10664
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Parameters behind “nonparametric” statistics: Kendall's tau, Somers' D and median differences AgEcon
Newson, Roger.
So-called “nonparametric” statistical methods are often in fact based on population parameters, which can be estimated (with confidence limits) using the corresponding sample statistics. This article reviews the uses of three such parameters, namely Kendall’s τα Somers’ D, and the Hodges–Lehmann median difference. Confidence intervals for these are demonstrated using the somersd package. It is argued that confidence limits for these parameters, and their differences, are more informative than the traditional practice of reporting only p-values. These three parameters are also important in defining other tests and parameters, such as the Wilcoxon test, the area under the receiver operating characteristic (ROC) curve, Harrell’s C, and the Theil median slope.
Tipo: Journal Article Palavras-chave: Confidence intervals; Gehan test; Harrell's C; Hodges–Lehmann median difference; Kendall's tau; Nonparametric methods; Rank correlation; Rank-sum test; ROC area; Somers' D; Theil median slope; Wilcoxon test; Research Methods/ Statistical Methods.
Ano: 2002 URL: http://purl.umn.edu/115950
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Statistical methods to study adaptability and stability of wheat genotypes Bragantia
Bornhofen,Elesandro; Benin,Giovani; Storck,Lindolfo; Woyann,Leomar Guilherme; Duarte,Thiago; Stoco,Matheus Giovane; Marchioro,Sergio Volmir.
ABSTRACT The sensitivity of wheat crop to environmental variations frequently results in significant genotype (G) x environment (E) interaction (GEI). We compared statistical methods to analyze adaptability and stability of wheat genotypes in value for cultivation and use (VCU) trials. We used yield performance data of 22 wheat genotypes evaluated in three locations (Guarapuava, Cascavel, and Abelardo Luz) in 2012 and 2013. Each trial consisted of a complete randomized block design with three replications. The GEI was evaluated using methodologies based on mixed models, analysis of variance, linear regression, multivariate, and nonparametric analysis. The Spearman’s rank correlation coefficient was used to verify similarities in the genotype selection...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Triticum aestivum L.; Univariate and multivariate methods; Rank correlation; Grain yield; Multi-environment trials.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052017000100001
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Test-day or 305-day milk yield for genetic evaluation of Gir cattle PAB
Pereira,Rodrigo Junqueira; Ayres,Denise Rocha; Santana Junior,Mário Luiz; Faro,Lenira El; Vercesi Filho,Aníbal Eugênio; Albuquerque,Lucia Galvão de.
Abstract: The objective of this work was to compare genetic evaluations of milk yield in the Gir breed, in terms of breeding values and their accuracy, using a random regression model applied to test-day records or the traditional model (TM) applied to estimates of 305-day milk yield, as well as to predict genetic trends for parameters of interest. A total of 10,576 first lactations, corresponding to 81,135 test-day (TD) records, were used. Rank correlations between the breeding values (EBVs) predicted with the two models were 0.96. The percentage of animals selected in common was 67 or 82%, respectively, when 1 or 5% of bulls were chosen, according to EBVs from random regression model (RRM) or TM genetic evaluations. Average gains in accuracy of 2.7, 3.0,...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Accuracy; Persistency; Random regression; Rank correlation.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2019000104305
Registros recuperados: 8
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