The purpose of this study was to compare estimates of genetic effects obtained using the additive-dominance model and another which included parameters for joint-additive (complementarity) and epistatic effects, as well as evaluate alternative objective criteria for choosing the lambda coefficient in ridge regression implementation. The results indicated that the criterion to be employed at the choice of lambda not only depends on the data set and the model used, but also on a previous knowledge about the phenomenon under study and the practical interpretation of estimated coefficients. When performing genetic effects evaluation, if other than additive and dominance effects are contemplated, it may be possible to identify and separate joint-additive and epistatic effects, which are usually inlaid in the heterotic effect estimated by the additive-dominance model. The use of ridge regression method can make such analyses possible even under strong multicollinearity.
biased estimation; epistasis; heterosis; multicollinearity; ridge regression
