Heritability, gain, and C effects in rooting of western hemlock cuttings

Analysis of clonal variation for five rooting traits of western hemlock (Tsugaheterophylla (Raf.) Sarg.) clones demonstrated that clonal variation was due to both genetic and C effects (i.e., physiological or morphological characteristics unique to the ortet because of its specific environment). The potential bias to genotypic values of clones owing to C effects was significant, but heritability and gain estimates were only slightly biased. The five rooting traits were highly heritable (H2 = 0.87–0.92), and predicted genetic gain from clonal selection was substantial. Genetic correlations between pairs of traits were generally high (0.66−0.99); therefore, when selecting for any one trait, correlated responses can be expected in other traits.