Table 5 **Pearson correlation of predictions of a test set consisting of 60 lines when predicted by additive and interaction effect estimates based on a model including 50, 100 or 150 markers and their pairwise interaction effects. The numbers represent the means of 200 repetitions with independently, uniformly drawn marker and test sets. The training set is given by the remaining 539 lines. The standard error of the estimate was in all cases smaller than 0.01. Colors indicate the underlying data: Environment 1, 2, 3 or 4.**