Dear Arthur Sorry but I need to ask..... Okay, say I fit a simple Mixed Model Yield ~ mu !r genotypes Now shouldn't the estimate of the ERROR Variance comp. be the same as the variance of the Residuals. (in the .sln file) i.e var(Residuals). Many thanks again Arthur. Kind Regards Vince Vince Matassa Department Of Agriculture BIOMETRICS SECTION University Of Queensland Brisbane 4072 Australia