Application of Reactions Norms in Study of Genotype Environmental Interaction for Milk Yield of Buffaloes

Nenhuma Miniatura disponível

Data

2013-01-01

Autores

Tonhati, Humberto [UNESP]
Aspilcueta-Borquis, Rusbel Raul [UNESP]
Freitas, Ana Claudia de [UNESP]
Ferreira de Camargo, Gregorio Miguel [UNESP]
Baldi, Fernando [UNESP]

Título da Revista

ISSN da Revista

Título de Volume

Editor

Int Buffalo Information Ctr

Resumo

The aim of this study was to estimate genetic parameters for milk yield (MY) in buffaloes using reaction norms. Model included the additive direct effect as random and contemporary group (herd and year of birth) were included as fixed effects and cow age classes (linear) as covariables. The animal additive direct random effect was modeled through linear Legendre polynomials on environment gradient (EG) standardized means. Mean trends were taken into account by a linear regression on Legendre polynomials of environmental group means. Residual variance was modeled trough 6 heterogeneity classes (EG). These classes of residual variance was formed : EG1: mean = 866,93 kg (621,68 kg-1011,76 kg); EG2: mean = 1193,00 kg (1011,76 kg-1251,49 kg); EG3: mean = 1309,37 kg (1251,49 kg -1393,20 kg); EG4: mean = 1497,59 kg (1393,20 kg-1593,53 kg); EG5: mean = 1664,78 kg (1593,53 kg -1727,32kg) e EG6: mean = 1973,85 kg (1727,32 kg -2422,19 kg).(Co) variance functions were estimated by restricted maximum likelihood (REML) using the GIBBS3F90 package. The heritability estimates for MY raised as the environmental gradient increased, varying from 0.20 to 0.40. However, in intermediate to favorable environments, the heritability estimates obtained with Considerable genotype-environment interaction was found for MY using reaction norms. For genetic evaluation of MY is necessary to consider heterogeneity of variances to model the residual variance.

Descrição

Palavras-chave

random regression, Legendre, environment gradient

Como citar

Buffalo Bulletin. Bangkok: Int Buffalo Information Ctr, v. 32, p. 662-665, 2013.