Interactions between genetics and environment in animal breeding

The results of a large number of experiments are summarised, conducted with layers, broiler chickens, turkeys and pigs aimed at determining the nature and magnitude of genotype - environment interactions. Special attention is devoted to sex as a very important genetic factor influencing the variance of the traits studied in broiler chicken, turkey and pigs and as a main fa ctor involved in causing sex - environment, sex - level of nutrition intera ctions. As the performance differences between commercial strains (hybrids) of broiler chicken, turkey and pigs diminish, the importance of the sex di fferences increase. The literature cited provides details regarding the top ics discussed.