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Doctoral thesis2016Open access

Quantitative genetics of Norway spruce in Sweden

Chen, Zhi-Qiang


Genetic improvement of solid wood and pulp and paper products related wood quality traits are important to increase productivity and value of Norway spruce plantation in Sweden. To incorporate wood quality traits into Norway spruce tree breeding program, genetic parameters of solid wood and fibre traits were investigated in a large Norway spruce population. 524 half-sib families from two trials tested in southern Sweden were selected to characterise the genetic variation in wood density, microfibril angle (MFA), modulus of elasticity (MOE), radial fibre width (RFW), tangential fibre width (TFW), fibre wall thickness (FWT), fibre coarseness (FC), and fibre length (FL). To rapidly measure stiffness (MOE) of standing trees and accurately measure FL from increment cores, a new non-destructive method for quantifying stiffness and a new algorithm for calculating FL were developed. A combination of Pilodyn and acoustic Hitman measurement was found to predict stiffness of standing tree accurately and the new algorithm using Expectation-Maximization could accurately estimate FL. To improve the estimate of genetic parameters and understanding genotype by environment (G×E) interaction in Norway spruce, spatial analyses were applied to 145 progeny trials and factor-analytic method was applied to 20 half-sib progeny trials. Spatial analysis significantly improved heritability and accuracy of breeding value prediction. Frost damage may be a main driver for G×E interaction for tree height of Norway spruce in southern and central Sweden. Wood quality traits showed higher heritability than growth traits. However, growth traits had highly unfavourable genetic correlations with solid wood quality traits (0.54-0.75) and weakly to moderately unfavourable genetic correlations with fibre property traits (0.11-0.49). In conclusion, selection based on diameter alone would have considerable negative effects on wood quality traits, a negligible or small negative effect on FL, and only a moderate effect on FWT. A selection index combining diameter and stiffness, which would have minimal impact on FL, is recommended for spruce breeding. Adequate economic weights for growth and stiffness traits should be determined for Norway spruce breeding program to maximize economic gain for Norway spruce.


Norway spruce; Quantitative genetics; Spatial analysis; Factor analytic; Fiber length; Solid wood quality; Index selection

Published in

Acta Universitatis Agriculturae Sueciae
2016, number: 2016:55ISBN: 978-91-576-8612-1, eISBN: 978-91-576-8613-8
Publisher: Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences