Genetic parameter estimates for wood stiffness, strength, internal checking, and resin bleeding for radiata pine

Data from two separate experiments were used to estimate genetic parameters for different wood properties of Pinus radiata D. Don in New Zealand. In experiment 1, 72 and 60 open-pollinated families were sampled at two sites, Kinleith and Paengaroa, respectively. Fifty-nine such families were common to both sites. In experiment 2, 62 and 29 pollen-parent families were sampled from a female-tester trial at two sites, Kaingaroa and Warrengong (the latter in Australia), respectively. Twenty-nine such families were common to both sites. Clearwood stiffness (MOE) and strength (MOR), wood density (DEN), acoustic stiffness on standing trees (IMLH), acoustic stiffness in 5-m logs (HITMAN), external resin bleeding (ERB), internal checking from discs taken at 1.3-m and 3.0-m height (CHEK_B and CHEK_U), and diameter at breast height (DBH) were assessed. Within-site narrow-sense heritability (h^2) estimates of various wood properties were consistent, particularly within New Zealand. Across-sites estimates of h^2 of HITMAN, CHEK_B, and DEN were, respectively, 0.24, 0.40, and 0.62 in experiment 1 and 0.21, 0.16, and 0.38 in experiment 2. Estimated type B genetic correlations were generally high for all traits except DBH. DEN showed strong positive genetic correlation with all direct and acoustic measures of stiffness (MOE, HITMAN, and IMLH). DEN and all measures of stiffness showed low to moderate negative genetic correlations with DBH.