Genotype-by-environment interaction and the genetic covariance between environments: multilocus genetics

Explicit multi-locus expressions for the genetic variance of a phenotypically plastic trait over a range of environments are derived. The link becomes apparent between the genetic covariance, the genotype-by-environment interaction variance and the variance for the main effect genotype in a two-factor analysis of variance over two environments and many known genotypes. The genetic correlation can be +1 even if the genotype-by-environment interaction variance is greater than zero.