Resumen
We studied genotype by environment interaction (G × E) for body weight (BW) of Atlantic cod (Gadus morhua L.) from the National cod breeding program in Norway. Records of 13,811 fish in a nucleus farm (NUC) and two test farms (PENorth, PESouth) in year-class (YC) 2007, and for 9149 fish in NUC and one test farm in YC 2010 were available. Heterogeneity of variances and heritabilities (h2" role="presentation" style="position: relative;">h2h2
h
2
) were estimated using a univariate animal model with environmental effects common to full-sibs (full-model). Genetic correlations (rg" role="presentation" style="position: relative;">????rg
r
g
) between farms were estimated using a multivariate full-model and a reduced-model (without
c2" role="presentation" style="position: relative;">??2c2
c
2
) for each YC. Heterogeneity of
h2" role="presentation" style="position: relative;">h2h2
h
2
was observed in both YC 2007 (0.10 to 0.16) and YC 2010 (0.08 to 0.26). The estimates of
rg" role="presentation" style="position: relative;">????rg
r
g
between NUC and test farms were relatively high for both models (0.81 ± 0.19 to 0.96 ± 0.17) and (0.81 ± 0.08 to 0.86 ± 0.04), suggesting low re-ranking of genotypes. Strong re-ranking of genotypes between PESouth and PENorth may be less important because most cod producers are situated close to the breeding nucleus. In conclusion, G × E between NUC and test farms were low and at present there is no need for separate breeding programs for BW in cod.