Estimation of additive and dominance genetic variances for body weight at harvest in rainbow trout, Oncorhynchus mykiss

Summary

Additive genetic, dominance genetic, and common environmental variance components were estimated for body weight at harvest for three populations of rainbow trout under selection for six generations in Norway. Six different models were studied by including all or different subsets of the following effects in an animal model: additive genetic (A), parental dominance (D), common environmental due to full-sibs (CE) and inbreeding coefficient (F) as a covariate. Variance components were estimated using the Average Information Restricted Maximum Likelihood (AIREML) method. In general, the results showed that estimates of additive genetic variance were inflated under the simple models (A) and (A + F), and decreased remarkably under the more complex models such as (A + CE), (A + CE + F), (A + D + F), and (A + D + CE + F). The magnitude of the dominance variance ranged from 0 to 22% and the common environmental variance from 0% to 6% of the total phenotypic variance. The study confirmed the presence of a significant dominance genetic variance for harvest body weight in rainbow trout. However, the results indicate that the dominance and common environmental effects may be confounded in the present data. (C) 2002 Elsevier Science B.V. All rights reserved.