Genetic Parameters of Stem and Wood Traits in Full-Sib Silver Birch Families

Grace Jones,Mateusz Liziniewicz,Stergios Adamopoulos,Johan Lindeberg

doi:10.3390/f12020159

Grace Jones, Mateusz Liziniewicz + Show 2 more

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https://doi.org/10.3390/f12020159

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Abstract

This study investigated heritability of stem and wood traits to improve Swedish silver birch (Betula pendula Roth.) through breeding. Birch is 12% of Sweden’s forest area but mainly used for low value pulp or firewood. This paper applied non-destructive test (NDT) methods, and estimated traits’ heritability (h2), to help breed birch for high value solid wood products. Two trials of 22 families were assessed at age 19 for stem diameter (DBH), stem straightness, rough brown bark height (BH), grain angle (GA), Pilodyn penetration depth (Pilo) and acoustic velocity (AV). X-ray densitometry was performed on a subsample of radial cores taken at 1.3 m from the ground to get an average benchmark density. The h2 values were moderate for GA (0.20 and 0.21) and Pilo (0.53 and 0.48) at the two sites, but the h2 values for AV were low (0.05 and 0.30). There were moderate genotypic correlations between BH and DBH (0.51–0.54). There were low genotypic and phenotypic correlations between NDT measurements and other traits so including NDT in birch breeding efforts should not inadvertently reduce size, stem or wood quality. The high genetic correlations between sites suggest that GA, Pilo and AV values were determined more by genotype than by environment.

Highlights

Received: 29 December 2020Over 12% of Sweden’s productive forest volume is composed of birch (Betula spp.) [1].The majority of harvested birch is used for pulp [2] or firewood production as it is considered to be low quality
Pilodyn penetration was under strong genetic control, and grain angle had moderate heritabilities with high genotypic variation
Genotypic and phenotypic correlations between growth traits measured at different ages were high, indicating that early selection is possible for size traits

Summary

Introduction

Received: 29 December 2020Over 12% of Sweden’s productive forest volume is composed of birch (Betula spp.) [1].The majority of harvested birch is used for pulp [2] or firewood production as it is considered to be low quality. The volume of high quality wood is presumably insufficient to sustainably supply a domestic wood products industry. Birch regularly occurs in forests managed for Norway spruce or Scots pine production [3] where there is limited interest in managing birch for high quality wood. These birches are scattered in pure or mixed softwood stands and naturally regenerated from unimproved material, especially during early succession stages, such as after clear-cutting or storm damage [3,4]. The current recommendations are to plant improved material and adopt specialized silvicultural practices to produce high-quality birch wood and increase the value of Sweden’s birch stands

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