Fig. 4. The standard deviation of performance (Fig. 3) for nine general classes of genetic models (Table 1). E = the number of different environment types conditioning gene-by-environment interactions in the target population of environments, and K = level of epistasis. Additive genetic models: E = 1, K = 0; Epistatic effects models: E = 1, K = 1, 2; Gene-by-environment effects models: K = 0, E = 5, 10; Epistasis and gene-by-environment effects models: E = 5, 10, K = 1, 2.