Interação genótipo – ambiente no peso ao sobreano na raça Nelore
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Data
2009-07-22
Autores
Solar Diaz, Iara Del Pilar [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Com o objetivo de estudar a interação genótipo – ambiente (IGA) no peso ao sobreano, foram utilizados 99.366 registros provenientes de diferentes rebanhos da raça Nelore de cinco estados brasileiros (São Paulo, Mato Grosso, Mato Grosso do Sul, Goiás e Minas Gerais). Os dados são provenientes de animais nascidos entre 1991 a 2006 participantes do Programa de Melhoramento Genético da Raça Nelore (PMGRN). As informações foram coletadas pelos próprios criadores, sendo posteriormente transferidas à Associação Nacional de Criadores e Pesquisadores (ANCP) e então incorporadas ao banco de dados. Neste estudo foram utilizados apenas os dados dos animais criados exclusivamente a pasto. Os componentes de (co)variância foram obtidos através de uma análise unicaracterística (onde considerou-se o peso como mesma característica em todos os estados) e multicaracterística (na qual considerou-se a expressão do peso em cada estado como uma característica distinta). As estimativas foram obtidas por meio de inferência bayesiana, e o modelo de análise incluiu os efeitos fixos de grupos de contemporâneos e, como aleatórios, os efeitos genético aditivo direto e residual. A interação genótipo - ambiente foi verificada através da correlação genética (rg). As interações foram consideradas importantes quando os valores de rg ficaram abaixo de 0,80. Posteriormente, verificou-se o efeito da interação sobre a seleção considerando uma análise uni ou multicaracterística. As estimativas de herdabilidade em Mato Grosso (0,39±0,03) e Mato Grosso do Sul (0,37±0,02) foram mais baixas que as encontradas em Goiás (0,51±0,02), São Paulo (0,44±0,02) e Minas Gerais (0,41±0,04). As correlações genéticas estimadas entre os pesos nos diferentes estados foram positivas...
The goal was to study genotype by environment interaction (GEI) for yearling weight. Records of 99,366 Nellore cattle from five Brazilian states (São Paulo, Mato Grosso, Mato Grosso do Sul, Goias and Minas Gerais) were used. Animals were born between 1991 to 2006 belonging to the Nellore Cattle Breeding Program (NCBP). Information was collected by farmers then, was transferred to the National Association of Breeders and Researchers (NABR) and incorporated into the database. This study used only data from animals raised exclusively on pasture. The (co)variance components were obtained using univariate (considering record as same trait in all states) and multiple-trait models, considering record from each state as a different trait. Estimates were obtained by Bayesian inference. The model for yearling weight included genetic fixed factor of contemporary groups and random animal genetic and residual effects. The genotype environment interaction was verified by genetic correlation (rg), where values below 0.80 indicated important interaction. Subsequently, the effect of interaction was verified on the selection considering a univariate or multiple-trait models. The direct heritability estimates of yearling weight in Mato Grosso (0.39±0.03) and Mato Grosso do Sul (0.37±0.02) were lower than Goiás (0.51±0.02), São Paulo (0.44±0.02) and Minas Gerais (0.41±0.04). The acrossstates estimates of genetic correlations were positive and moderate (0.67 to 0.75) between the states Goiás and Mato Grosso, Goias and Minas Gerais, São Paulo and Minas Gerais, and between Mato Grosso do Sul and Minas Gerais. These estimates indicates that genotype by environment interactions are biologically important. These results show that the animals selected will not be the same depending of the considered state, reducing the response... (Complete abstract click electronic access below)
The goal was to study genotype by environment interaction (GEI) for yearling weight. Records of 99,366 Nellore cattle from five Brazilian states (São Paulo, Mato Grosso, Mato Grosso do Sul, Goias and Minas Gerais) were used. Animals were born between 1991 to 2006 belonging to the Nellore Cattle Breeding Program (NCBP). Information was collected by farmers then, was transferred to the National Association of Breeders and Researchers (NABR) and incorporated into the database. This study used only data from animals raised exclusively on pasture. The (co)variance components were obtained using univariate (considering record as same trait in all states) and multiple-trait models, considering record from each state as a different trait. Estimates were obtained by Bayesian inference. The model for yearling weight included genetic fixed factor of contemporary groups and random animal genetic and residual effects. The genotype environment interaction was verified by genetic correlation (rg), where values below 0.80 indicated important interaction. Subsequently, the effect of interaction was verified on the selection considering a univariate or multiple-trait models. The direct heritability estimates of yearling weight in Mato Grosso (0.39±0.03) and Mato Grosso do Sul (0.37±0.02) were lower than Goiás (0.51±0.02), São Paulo (0.44±0.02) and Minas Gerais (0.41±0.04). The acrossstates estimates of genetic correlations were positive and moderate (0.67 to 0.75) between the states Goiás and Mato Grosso, Goias and Minas Gerais, São Paulo and Minas Gerais, and between Mato Grosso do Sul and Minas Gerais. These estimates indicates that genotype by environment interactions are biologically important. These results show that the animals selected will not be the same depending of the considered state, reducing the response... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Bovino de corte, Teoria bayesiana de decisão estatistica, Seleção, Correlação genética, Beef cattle, Bayesian inference, Genetic correlation, Multiple-trait model, Selection
Como citar
SOLAR DIAZ, Iara Del Pilar. Interação genótipo – ambiente no peso ao sobreano na raça Nelore. 2009. x, 58 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2009.