Genotype x environment interactions in animals: Theoretical considerations and review of findings

Abstract

The phenotype of an individual animal is a function of its genotype and environment. It is the sole information available to the animal breeder for evaluating the breeding values of the animals whether measurements are made on the individuals or on their relatives. The problem of evaluation would be easy if the effects of genotype and environmenr on the phenotype were just additive. But, in addition to their additive effects, there may be a non-additive relationship between genotype and environment, as was recognized by Wright (1939) among others of that time.