Location-year combinations were treated as environments, and environment-population combinations were treated as experiments.
Thus the multienvironment model contains a main effect that is common across environments and environment-specific effects that allow for departures from the common effect.
First, the experiments were certainly effective in detecting differences among populations (VR.oil showed the highest survival in multiple environments) and environments (oil-polluted environments reduced survival and growth).
In the full model, the interactions of genotype by environment and environment by environment were also tested (Table 1).
Both tests confirmed our experimental setup and indicated a marginal contribution of the environment and environment × genotype interactions.
In the across environment combined analysis, genotypes were considered as fixed effect, days to flowering was considered as a fixed covariate nested within environment, and environment, genotype × environment interaction (G × E), and replication within environment were treated as random effects.
Mixed models were run using PROC MIXED in SAS (version 9.3; SAS Institute, Gary NC) with line, environment, and environment × line interaction as random effects.
The interactions of gene-gene, gene-environment, and environment-environment on serum lipid levels are remained to be determined.
We also tested for environment and environment-by-heat shock temperature interactions within each selection line.
Since various factors, including race, culture, socioeconomic status, and place of residence, determine the degree of exposure to various environmental triggers, birth cohort studies are vital for identifying these gene-environment and environment-environment interactions [ 13].
