The potential for breeding Pinus radiata D. Don to improve wood stiffness (modulus of elasticity, MoE) was examined by obtaining pith-to-bark cores from trees at breast height in two independent genetic trials. The effectiveness of early selection for stiffness and indirect selection on the component traits, microfibril angle (MfA) and wood density, was determined as well as the age-related changes in the genetic variation of these traits. The first trial comprised 50 open-pollinated families in the central North Island, New Zealand. The second trial comprised 20 control-pollinated families in New South Wales, Australia. The genetic control of MfA, density, and MoE was found to be high in the corewood and moderate in the outerwood. Estimated genetic correlations suggested that early selection for most traits would be successful but could be carried out slightly earlier at the New Zealand site than at the Australian site. To maximize gain in the corewood, selection for MoE and MfA would be most effective around rings 4-8. There were no adverse correlations between MoE and MfA or density, implying that selection for MoE would also improve MfA and density.

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The use of calibrated near-infrared (NIR) spectroscopy for predicting the radial variation of the longitudinal modulus of elasticity (E L ) of increment cores is described. Sets of Eucalyptus delegatensis R.T. Baker (alpine ash) and Pinus radiata D. Don (radiata pine) samples were characterized in terms of E L(SS) (estimated stiffness based on a combination of SilviScan-2 diffractometric data and measured density (R. Evans and J. Ilic. 2001. For. Prod. J. 51(3): 53-57)). NIR spectra, obtained from the radial-longitudinal face of each sample, were used to develop E L(SS) calibrations for the E. delegatensis and P. radiata sample sets and the two sets combined. The relationships between laboratory-determined E L(SS) and NIR-fitted E L(SS) were good in all cases. E L(SS) was estimated in separate test sets and found to correlate well with measured E L . NIR spectra were obtained in 15-mm sections from the radial-longitudinal face of two intact P. radiata increment cores. E L(SS) of each section was estimated using the P. radiata and the combined P. radiata and E. delegatensis calibrations. NIR estimates of E L(SS) were in good agreement with SilviScan-2 determined stiffness indicating that NIR spectroscopy can be successfully used to estimate radial variation in wood stiffness of increment cores.Résumé : Cet article décrit l'utilisation de la spectroscopie dans le proche infrarouge pour prédire la variation radiale du module d'élasticité dans le sens longitudinal (E L ) dans des carottes de bois. Des groupes d'échantillons d'Eucalyptus delegatensis R.T. Baker (eucalyptus des montagnes) et de Pinus radiata D. Don (pin de Monterey) ont été caracté-risés en terme de E L(SS) (résistance estimée sur la base d'une combinaison de données diffractométriques obtenues via SilviScan-2 et de mesures de densité (R. Evans et J. Ilic. 2001. For. Prod. J . 51(3): 53-57)). Le spectre dans le proche infrarouge, obtenu de la face radiale dans le sens longitudinal de chaque échantillon, a été utilisé pour établir des courbes d'étalonnage pour la valeur de E L(SS) avec les échantillons de E. delegatensis et P. radiata séparément et regroupés. Les relations entre les valeurs de E L(SS) mesurées en laboratoire et les valeurs obtenues par les équations développées pour l'analyse par spectroscopie dans le proche infrarouge sont bonnes dans tous les cas. Les valeurs de E L(SS) estimées par des tests indépendants sont étroitement corrélées avec les valeurs mesurées de E L . Les spectres dans le proche infrarouge ont été obtenus pour des sections radiales de 15 mm dans le sens longitudinal de deux carottes intactes de P. radiata. La valeur de E L(SS) de chaque section a été estimée à l'aide des courbes d'étalonnage pour P. radiata et pour P. radiata et E. delegatensis combinés. Les estimations de la valeur de E L(SS) sur la base de la spectroscopie dans le proche infrarouge correspondent bien aux valeurs de résistance déterminées avec SilviScan-2, ce qui indique que la spectroscopie dans le proche infrarouge peut-être utilisée avec succès pour...

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A new breeding strategy is presented for the Radiata Pine Breeding Company, a New Zealand based research consortium, that drives the breeding program for Pinus radiata for both the New Zealand and New South Wales based Australian forest plantation industry. The new strategy builds on the existing base for P. radiata, and on the last strategy review in 2000. The new strategy comprises a large open-pollinated (OP) Main Population (MP) with 500 female parents and two sublines (250 female parents per subline). The MP will be tested using alpha designs, single-tree plots and incomplete blocks to maximise efficiency. Each subline will be tested on four sites, geographically distant from the other subline. The MP will be managed in discrete generations. Selection of the next generation will be using a combination of backward and forward selection, but the strict control of inbreeding with identified lineage will rely on the development of parental reconstruction for OP progeny. There are alternatives to this, however, such as estimating the group coancestry and accepting some additional increase in inbreeding. This is a new and significant departure from previous breeding strategies for P. radiata in New Zealand. There will also be a single, small Elite Population (EP), tested 50% as progeny and 50% as clones. Twenty four parents will be tested each year as clones and 24 as seedling progeny with some overlap between the two. It is expected that the clonal population will capture the greatest gains in traits with low heritabilities, and the half-sib progeny will capture the greatest gains in traits with high heritabilities. The two sublines will be maintained in the EP, and breeding will be managed as a rolling front with trials established every year, while trials of the MP will be established every 10 years.