respectively. Then for each G level we assumed that the Phenotypes were linearly dependent on the environmental variable with the error having a normal distribution with mean = 0 and SD = 0.1. Figure 2 presents simulated data and observed regression lines from the four parameter and six parameter models for three scenarios in which a different one of the three constraints is violated in each one. In Figs. 2a, b and c the linear dependence of P on E for the G levels 0, 1 and 2 has the forms: P(G=0)=Intercept0+slope0⋅EP(G=1)=Intercept1+slope1⋅EP(G=2)=Intercept2+slope2⋅E. Intercept and Slope coefficients are given in Table 1.
