Prediction of the response to a selection for canalisation of a continuous trait in animal breeding

Canalising selection is handled by a heteroscedastic model involving a genotypic value for the mean and a genotypic value for the log variance, associated with a single phenotypic value. A selection objective is proposed as the expected squared deviation of the phenotype from the optimum, of a progeny of any candidate for selection. Indices and approximate expressions of parent-offspring regression are derived. Simulations are performed to check the accuracy of the analytical approximation. Examples of fat to protein ratio in goat milk yield and muscle pH data in pig breeding are provided in order to investigate the ability of these populations to be canalised towards an economic optimum. (C) Inra/Elsevier, Paris.