The effects of model on genetic parameters of body weight traits in two white and wild Japanese quail populations

In this study, the genetic parameters of body weight traits including body weights at birth, 7, 14, 21, 28 and 35 days were investigated in Japanese quail. For this aim, two Japanese white and wild quail populations and two types of pure and cross mating methods were used. The data were analysed with different animal models and restricted maximum likelihood (REML) procedures, using ASREML software. Six different animal models were implemented and were compared by likelihood ratio test. All models consisted of the direct additive genetic effect, but differed in combinations of maternal additive genetic, maternal environmental and covariance between direct and maternal additive genetic effects. Based on the results of Chi Square, the model including direct additive genetic, maternal additive genetic and environmental maternal effects was considered as the most appropriate model for genetic evaluation of birth weight. Based on this model, the direct heritability (h2a), maternal heritability (h2m), and the ratio of maternal environmental variance to phenotypic variance (c2) of birth weight were estimated 0.13±0.01, 0.48±0.01 and 0.06±0.01, respectively. For other body weight traits, a simple model that included the direct additive genetic effect was selected as the appropriate model. Direct heritability for body weight traits from 7 to 35 days was ranged from 0.29 to 0.39. The results of this study showed that maternal effects were significant only on birth weight of Japanese quails, and at older ages, the bird's genes play a major role to determine the weight traits