Genetic variation in Eucalyptus nitens pulpwood and wood shrinkage traits

Abstract

Eucalyptus nitens plantations are generally established for pulpwood production but an increasing area is being managed for solid wood. Genetic variation in, and correlations among, three Kraft pulpwood traits (diameter at breast height, basic density and near-infrared-predicted cellulose content) and three 12-mm wood-core shrinkage traits (recoverable collapse, net shrinkage and gross shrinkage) were examined, utilising data from two 9-year-old firstgeneration progeny trials in Tasmania. These trials contained approximately 400 open-pollinated families (over 100 of which were sampled for wood properties) representing three central-Victorian E. nitens races. Significant genetic variation at the race and/or within-race level was identified in all traits. Within races, relative levels of additive genetic variation were higher for shrinkage traits, although narrowsense heritabilities were lower and the expression of genetic variation less stable across sites than for other wood property traits. Heterogeneous intertrait genetic correlations were identified across sites between growth and some wood property traits. However, where significant, genetic correlations indicated that within-race selection for growth would adversely affect core basic density and all core shrinkage traits. Furthermore, results based on cores suggested that within-race selection for higher basic density would favourably impact on cellulose content and collapse but selection for either higher basic density or cellulose content would adversely affect net shrinkage. Most within-race genetic variation in gross shrinkage appeared to be due to genetic variation in collapse. The implications of these results for sawn timber breeding will depend on the strength of genetic correlations between core traits and rotation-age objective traits and objective trait economic weights.

Heritability of growth strain in Eucalyptus bosistoana: a Bayesian approach with left-censored data§

“…Density, diameter at age 2 (growth), volumetric shrinkage, acoustic velocity and stiffness all have significantly large heritability, suggesting that breeding for these traits is achievable. The heritabilities are similar to those reported for other eucalypt species (Hung et al 2014;Hein et al 2012;Blackburn et al 2010;Blackburn et al 2014;Hamilton et al 2008). Wood processors pay premiums for stable and stiff timber, while forest growers often prefer to have fastgrowing trees as to shorten rotation lengths increasing profitability.…”

Acoustic Wave Velocity as a Selection Trait in Eucalyptus nitens

“…Basic density was assessed using the water displacement method [34]. At Meunna and Tarraleah basic density was assessed on 12 mm radial wood cores extracted from trees at a height of 0.9 m (core basic density) at age nine years [35] (Table 2). At Tarraleah and Southport, disks approximately 50 mm thick were extracted at a height of 5.8 m from the same trees assessed for AWV at ages 13 and 14 (Tarraleah), and 19 years (Southport) respectively.…”

Comparison of Pyrolysis Mass Spectrometry and Near Infrared Spectroscopy for Genetic Analysis of Lignocellulose Chemical Composition in Populus

“…For Pinus pinaster Ait and Pinus taeda, Isik et al [52], Perez et al [34] and Gaspar et al [35] showed NIR as a potential tool to estimate heritabilities and genetic correlations for tree selection in physical and chemical properties. For Eucalyptus globulus and Eucalyptus nitens, the application of NIR focused on predicting the genetic parameters for cellulose [28,33], pulp yield [12,30,31], lignin [29]. Schimleck et al [15,32] investigated the cellulose content predicted with a NIR calibration model as an alternative to estimate Kraft pulp yield in Eucalyptus nitens.…”