Miloš Ivković

Genetic correlations among juvenile wood quality and growth traits and implications for selection strategy in Pinus radiata D. Don

Abstract• Juvenile wood quality in Pinus radiata is affected by factors such as low density, stiffness, and high microfibril angle, spiral grain, and shrinkage. Adverse genetic correlations between growth and wood quality traits remain as one of the main constraints in radiata pine advanced generation selection breeding program.• Juvenile wood property data for this study were available from two progeny tests aged 7 and 6 y. We estimated the genetic correlations between stiffness, density, microfibril angle, spiral grain, shrinkage in the juvenile core and DBH growth in radiata pine, and) to evaluated various selection scenarios to deal with multiple objective traits.• Negative genetic correlations were found for modulus of elasticity (MoE) and density with microfibril angle, spiral grain, shrinkage, and DBH. We observed low to moderate unfavourable genetic correlations between all wood quality traits and DBH growth.• These low to moderate genetic correlations suggest that there may be some genotypes which have high DBH growth performance while also having high wood stiffness and density, and that the adverse correlation between DBH and MoE may not entirely prohibit the improvement of both traits. Results indicate that, in the short term, the optimal strategy is index selection using economic weights for breeding objective traits (MAI and stiffness) in radiata pine.• In the long-term, simultaneously purging of the adverse genetic correlation and optimizing index selection may be the best selection strategy in multiple-trait selection breeding programs with adverse genetic correlations.Résumé• La qualité du bois juvénile chez Pinus radiata est affectée par des facteurs tels que la faible densité, la rigidité, et un angle de microfibrille grand, la fibre torse, et les fentes de retrait. Les mauvaises corrélations génétiques entre la croissance et les caractéristiques de la qualité du bois restent l’une des principaux obstacles à un programme poussé d’amélioration de Pinus radiata. Les données sur les propriétés du bois juvénile pour cette étude étaient disponibles à partir de deux tests de descendance âgés de 7 ans et 6 ans. Nous avons estimé les corrélations génétiques entre la rigidité, la densité, l’angle des microfibrilles, la fibre torse, les fentes de retrait dans le cœur juvénile et la croissance en diamètre à hauteur de poitrine (DBH) de Pinus radiata, et pour évaluer différents scénarios de sélection pour faire face à de multiples caractéristiques objectives.• Des corrélations génétiques négatives ont été trouvées pour le module d’élasticité (MoE) et la densité avec l’angle des microfibrilles, la fibre torse, les fentes de retrait, et la croissance en diamètre à hauteur de poitrine (DBH). Nous avons observé des corrélations génétiques défavorablement faibles à modérées entre toutes les caractéristiques de la qualité du bois et la croissance en diamètre à hauteur de poitrine (DBH).• Ces corrélations génétiques faibles à modérées suggèrent que peut être certains génotypes, ont une croissance importante en diamètre à hauteur de poitrine (DBH) tout en ayant une rigidité et une densité du bois élevée, et que les corrélations défavorables entre DBH et MoE peuvent ne pas interdire entièrement l’amélioration de ces deux caractéristiques. Les résultats indiquent que, dans le court terme, la stratégie optimale est l’index de sélection en utilisant le poids économique pour un objectif d’amélioration des caractéristiques (AMI et rigidité) chez Pinus radiata.• À long terme, à la fois la purge de la corrélation génétique défavorable et l’optimisation de l’index de sélection peut être la meilleure stratégie de sélection multicaractère dans les programmes sélection amélioration ayant des corrélations génétiques défavorables.

Genetic parameters and provenance variation of Pinus radiata D. Don. ‘Eldridge collection’ in Australia 1: growth and form traits

Growth and form traits data were obtained from eight provenance trials of radiata pine (Pinus radiata D. Don) planted across the radiata pine plantation estate in southeast Australia. The genetic pool included 466 open-pollinated families collected from Año Nuevo, Monterey and Cambria provenances on the Californian mainland coast in the USA and from Guadalupe and Cedros islands off the coast of Baja California in Mexico. Early survival of all provenances was around 90%, except for Cedros (<60%). Monterey and Año Nuevo were the best performers at almost all sites. However, good growth performance of Cambria and good stem straightness of Guadalupe on some sites are important results, because the genetic base of the present Australian plantations evidently originated from only Monterey and Año Nuevo. The average estimated single-site heritability for diameter at breast height was 0.22 and 0.32 at juvenile and mature ages, respectively. Heritability estimates for stem straightness and branching ranged from 0.23 to 0.55. Genetic correlation estimates between diameter at breast height (DBH) at juvenile and rotation ages were all >0.80. Estimates of between-site genetic and provenance correlations for DBH were often low, indicating high genotype by environment interaction across trials, consistent with previous Australian studies. However, there was minimal G × E among trials on high-altitude high-rainfall sites and among trials on low-altitude, low-rainfall sites.

Influence of cambial age and climate on ring width and wood density in Pinus radiata families

Abstract• ContextThe correlation between tree ring width and density and short-term climate fluctuations may be a useful tool for predicting response of wood formation process to long-term climate change.• AimsThis study examined these correlations for different radiata pine genotypes and aimed at detecting potential genotype by climate interactions.• MethodsFour data sets comprising ring width and density of half- and full-sib radiata pine families were used. Correlations with climate variables were examined, after the extraction of the effect of cambial age.• ResultsCambial age explained the highest proportion of the ring to ring variation in all variables. Calendar year and year by family interaction explained a smaller but significant proportion of the variation. Rainfall had a positive correlation with ring width and, depending on test site, either a negative or positive correlation with ring density. Correlations between temperature during growing season and ring density were generally negative.• ConclusionClimate variables that influence ring width and wood density can be identified from ring profiles, after removing the cambial age effect. Families can be selected that consistently show desirable response to climate features expected to become prevalent as a result of climate change.

Genetic parameters and provenance variation of Pinus radiata D. Don. 'Eldridge collection' in Australia 2: wood properties

Provenance variation and genetic parameters for wood properties of mature radiata pine (Pinus radiata D. Don) were studied by sampling three provenance/progeny trials in southeast Australia. Among the mainland provenances, Monterey and Año Nuevo had higher density and modulus of elasticity (at one site) than Cambria. Basic density and predicted modulus of elasticity (MoE) for the island provenances, Guadalupe and Cedros, were ∼20% higher at Billapaloola compared to mainland provenances grown at Green Hills and Salicki, differences that may or may not be linked to site differences. Heritability estimates of density, predicted MoE and microfibril angle were significant and

Pattern of genotype by environment interaction for radiata pine in southern Australia

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Risks Affecting Breeding Objectives for radiata pine in Australia

 > 0.45, suggesting moderate to strong genetic control. The estimated genetic correlations between diameter at breast height and wood properties in the current study were weaker (less negative) than the mean estimated from the current breeding population generation in radiata pine. Of the wood properties, density showed the strongest adverse genetic correlations with growth (mean rA = −0.23 ± 0.09). Selection for MoE may produce greater gain than selection for density because MoE had almost twice the estimated additive genetic coefficient of variation (

A framework for testing radiata pine under projected climate change in Australia and New Zealand

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