What is realized heritability?

Realized heritability refers to the proportion of phenotypic variance in a trait that can be attributed to genetic variance, as measured in a specific population and environment. It is often estimated by the response to selection in a breeding program, indicating how much a trait can be expected to improve through selective breeding. Unlike narrow-sense heritability, which focuses on additive genetic variance, realized heritability takes into account all genetic contributions, including dominance and epistatic interactions. It provides insights into the effectiveness of selection in improving traits over generations.