Heritability and phenotypic and genetic correlations of coastal Douglas-fir (Pseudotsuga menziesii) wood quality traits
2008
Ukrainetz, N.K. | Kang, K.Y. | Aitken, S.N. | Stoehr, M. | Mansfield, S.D.
Genetic control and relationships among coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) growth and wood quality traits were assessed by estimating heritability and phenotypic and genetic correlations using 600 trees representing 15 full-sib families sampled from four progeny test sites. Heritability estimates ranged from 0.23 to 0.30 for growth traits, 0.19 for fibre coarseness, from 0.21 to 0.54 for wood density, from 0.16 to 0.97 for cell wall carbohydrates, and 0.79 and 0.91 for lignin content at two sites, Squamish River and Gold River, respectively. Glucose content, indicative of cell wall cellulose composition, and lignin were shown to be under strong genetic control, whereas fibre coarseness was shown to be under weak genetic control. Phenotypic correlations revealed that larger trees generally have longer fibres with higher fibre coarseness, lower density, lower carbohydrate content, a greater proportion of cell wall lignin, and higher microfibril angle. Genetic correlations and correlated response to selection suggest that breeding for height growth would result in a reduction in wood quality, whereas breeding for improved earlywood density in Douglas-fir would result in negligible reductions in volume and appears to be an ideal target for selecting for improved wood quality (density) while maintaining growth in the sample population.
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