Abstract
Realized genetic gains of initial height growth caused by within-family selection of the F1 seedling seed orchard for Kunugi (Quercus acutissima) plus trees were compared with predicted ones. Predicted genetic gains for 50% within-family selection of the F1 seedling seed orchard were a 3.4% increase in height growth based on 4-year height growth data. This F1 seedling seed orchard consisted of 22 open-pollinated families. Realized genetic gains, which were 4.0% in height growth, were evaluated by analyzing 5-year height growth data collected from the F2 seedling seed orchard. This F2 seedling seed orchard comprised 6 open-pollinated F2 families and 6 open-pollinated F1 families. The realized genetic gains were comparable to the predicted ones. The mean height of the F2 family population outperformed that of the F1 family population, and the gains were statistically significant. The results of this study confirmed the efficiency of the seedling seed orchard procedure for Kunugi plus trees.
