Comparison of variances of directional genetic effects with and without recombinant inbred lines.

RIL-based traditional line cross equations and variance reduction under the assumption of equal variances in the estimate of the means in all generations. Typically, RIL populations will have a lower variance for the estimate of the mean because of their larger sample size. zXi = the phenotypic mean of the Xith generation (eg. zF1 = mean of the F1 generation).