The potential to improve growth rate and quality traits of stem straightness and branching habit when breeding Picea sitchensis (Bong.) Carr

Table 2 Estimated variance components calculated using REML along with their proportion of total phenotypic variance

Trait	\( \sigma_{{\rm f} }^2 \)	\( \frac{{\sigma_{{\rm f} }^2}}{{\sigma_{{\rm p} }^2}} \times 100 \) (%)	\( \sigma_{{{\rm fr} }}^2 \)	\( \frac{{\sigma_{{{\rm fr} }}^2}}{{\sigma_{{\rm p} }^2}} \times 100 \) (%)	\( \sigma_{{\rm e} }^2 \)	\( \frac{{\sigma_{{\rm e} }^2}}{{\sigma_{{\rm p} }^2}} \times 100 \) (%)	h ²_i	h ²_f
Height₁₀ (m)	0.028	6.98	0.045	11.22	0.328	81.80	0.28 (0.032)	0.48 (0.123)
Height₂₀ (m)	0.205	14.31	0.063	4.40	1.165	81.30	0.57 (0.045)	0.69 (0.174)
Crown depth₂₀ (m)	0.241	14.96	0.026	1.61	1.344	83.43	0.60 (0.046)	0.71 (0.178)
DBH₁₅ (cm)	0.276	6.41	0.154	3.58	3.875	90.01	0.26 (0.031)	0.49 (0.119)
Branch number₂₀	0.136	4.99	0.285	10.46	2.303	84.54	0.20 (0.028)	0.39 (0.107)
Branch angle₂₀ (^o)	9.084	13.69	0.000	0.00	57.293	86.31	0.55 (0.044)	0.70 (0.170)
Branch diam.₂₀ (mm)	1.016	7.42	0.000	0.00	12.68	92.58	0.30 (0.033)	0.55 (0.126)
Branch score ^a₁₅	0.113	12.60	0.059	6.58	0.725	80.82	0.50 (0.042)	0.65 (0.163)
Stem score ^a₁₅	0.080	6.26	0.066	5.17	1.131	88.57	0.25 (0.030)	0.47 (0.117)

Individual and family heritabilities calculated from the estimated variance components and their standard errors are also given in parentheses. Subscript on the trait description is the tree age when the measurements were made
\( \sigma_{{\rm f} }^2 \) = variation between family means
\( \sigma_{{fr}}^2 \) = family by replication interaction
\( \sigma_e^2 \) = environmental variation
\( \sigma_{{\rm p} }^2 \) (phenotypic variation) = \( \sigma_f^2 + \sigma_{{fr}}^2 + \sigma_{{\rm e} }^2 \)
^aBranch and stem scores range from 1 = best to 6 = worst

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