DISTRIBUTION OF TESTING EFFORT IN CLONED GENETIC TESTS

Forest tree populations were simulated to investigate the effects of G xE (5%, 25%, or 50% of genetic variances), number of breeding clones ( 40 or 64), and selection strategy on the optimum distribution of effor t between number of sites (1 to 6), individuals per family (8 to 156), and ramets per individual (1 to 6) under a fixed resources clonal tes ting and production scenario. Breeding and population gains, and relia bilities of estimates of population additive genetic variance were com pared among all combinations of factors to determine the optimum range s. Optimal distribution of testing effort was similar for maximizing p roduction and breeding population gains and for accurately estimating true population additive genetic variance, with 1 to 2 ramets distribu ted over 2 to 6 sites being in the optimal range. The optimal distribu tion was sensitive to levels of GxE. More families tested resulted in decreased gains in the breeding populations (lower within-family selec tion intensity, less precise half- and full-sib mean estimates). Highe r levels of GxE resulted in less gain under all scenarios except when testing occurred on 4 or more sites, in which case there were no signi ficant differences. Accuracy of estimates of additive genetic variance was improved with less families (more individuals per family) and low er levels of GxE when tested on less than 4 sites.