Genetic variation in rootability of cuttings from one-year-old western hemlock seedlings.

One-year-old western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings from three open-pollination families from eight locations in the Washington and Oregon Coast Ranges were cultured under accelerated growth conditions in a glasshouse. Forty cuttings from each of five seedlings (open-pollination siblings) per family were then placed in a rooting box in a randomized block design with five replications. Percent of cuttings rooted after one year in the bed was analyzed in a hierarchal design. Average rooting percentage was 72.4 percent. Significant effects were associated only with replication, siblings-in-families-in-provenances (S/F/P) and with the interaction, S/F/P x replication. The last two together accounted for 73 percent of the variance. The results indicated that additive genetic effects were not important to rooting success, but that dominance and unique clone-effects probably were.