Genetics of Growth Reaction Norms in Farmed XXXX .

@entity2828 @entity5660 @entity74
UNASSIGNED: @entity5660 is farmed globally under diverse uncontrollable environments. Fish with low macroenvironmental sensitivity ( @entity2828 ) of growth is important to thrive and grow under these uncontrollable environments. The @entity2828 may evolve as a correlated response to selection for growth in one environment when the genetic correlation between @entity2828 and growth is nonzero. The aims of this study were to quantify additive genetic variance for @entity2828 of body weight (BW), defined as the slope of reaction norm across breeding environment (BE) and production environment (PE), and to estimate the genetic correlation (rg(int, sl)) between BW and @entity2828 . To estimate heritable variance of @entity2828 , the coheritability of @entity2828 was derived using selection index theory. The BW records from 43,040 @entity5660 performing either in freshwater or seawater were analysed using a reaction norm model. High additive genetic variance for @entity2828 (9584) was observed, inferring that genetic changes in @entity2828 can be expected. The coheritability for @entity2828 was either -0.06 (intercept at PE) or -0.08 (intercept at BE), suggesting that BW observation in either PE or BE results in low accuracy of selection for @entity2828 . Yet, the rg(int, sl) was negative (-0.41 to -0.33) indicating that selection for BW in one environment is expected to result in more sensitive fish. To avoid an increase of @entity2828 while selecting for BW, it is possible to have equal @entity74 in BW in both environments so that @entity2828 is maintained stable.
