Luis A. Apiolaza

Heritability and fitness-related consequences of squid personality traits

Dumpling squid, Euprymna tasmanica, show consistent individual differences in behaviour that can be classified according to indices reflecting shy–bold, activity and reactivity responses. Using crosses of wild‐caught single males to multiple females with known behavioural phenotypes, this study estimated patterns of additive genetic and residual variance in these behavioural traits from offspring of squid in two contexts, a threat (antipredator) and feeding (foraging) test. Genetic contributions to behavioural expression were dependent on test context. Behaviours in antipredator contexts had significant heritabilities (h2 = 0.2–0.8) while behaviours from foraging contexts had lesser additive genetic and greater residual components (h2 = 0.05–0.08). Personality trait variation in females was not related to her fecundity. Female boldness in foraging situations, which co‐varied with body size, explained small but significant variation (∼21%) in brood hatching success, while successful fertilization was determined by positive assortion of mate pairs according to their shy–bold phenotype. These results are discussed in terms of the ecological and evolutionary significance of animal ‘personality’ traits in wild populations of animals.

Genetic variation of physical and chemical wood properties

Abstract This study considered the degree of genetic variation for diameter (DBH), basic density (BD), predicted pulp yield (PPY), fibre length (FL), microfibril angle (MFA) and cellulose content (CC) amongst eight subraces of Eucalyptus globulus growing in a field trial in NW Tasmania. There were significant subrace effects for BD, FL and CC. This variation affected the relative profitability of the subraces for pulp production. On average, the most profitable subraces (on NPV/ha over the base population mean) were Strzelecki Ranges (

Very early selection for solid wood quality: screening for early winners

862.04), Western Otways (

Genetic control of coppice and lignotuber development in Eucalyptus globulus

657.80) and Strzelecki Foothills (

Genetic control of very early compression and opposite wood in Pinus radiata and its implications for selection

576.81). The genetic control (heritability) of variation in DBH, FL and MFA was moderate (0.15 < h2< 0.27), while control for BD, PPY and CC was high (h2> 0.40). Genetic correlations between growth and wood properties were not statistically significant, except for DBHMFA (-0.86). Most genetic correlations amongst wood properties were outside the parametric space (< -1 or >1), but there were significant correlations between BDMFA (-0.70) and PPY-CC (0.82). The empirical response to selection on an index based on a pulp wood objective (which included volume and basic density) resulted in a gain of 4.3% for DBH, 7.9% for BD and marginal changes for all other traits, with a net impact in profit of

Characterization of mechanically perturbed young stems: can it be used for wood quality screening?

1,270/ha. However, future profit calculations will need to consider the effect of FL, MFA and CC on the economics of wood processing to fully evaluate the economic impact of breeding.

Integrating revenues from carbon sequestration into economic breeding objectives for Eucalyptus globulus pulpwood production

Abstract• This article reviews the theoretical basis for indirect selection — where early selection is an example — and how correlated response is calculated.• The review is followed by a description of issues as to the choice of selection criteria that could explain the lack of substantial progress on breeding for wood quality. These include: the autoregressive nature of selection criteria, overemphasizing the importance of basic density as selection criterion, ignoring age-related trends of wood properties, using rotation age rather than technical thresholds as objective traits and ignoring that not all grades have identical marginal economic value.• Three data sets are either analyzed for the first time or reanalyzed under different assumptions, to explore the importance of these criticisms.• Finally, the use of critical value thresholds as very early selection criteria is suggested and discussed in the context of improving intrinsic corewood quality.Résumé• Cet article passe en revue les bases théoriques des méthodes de sélection indirecte — parmi lesquelles figure la sélection précoce — et la manière dont le gain corrélé est calculé.• Cette revue est suivie d’une description des problèmes liés au choix des critères de sélection et qui pourraient expliquer le manque de progrès substantiel suite à l’amélioration pour les propriétés du bois. Ceux-ci incluent l’auto-corrélation des critères de sélection, l’exagération de l’importance de la densité comme critère de sélection, l’oubli de l’évolution des propriétés du bois avec l’âge cambial, l’utilisation de l’âge de révolution comme caractère-cible plutôt que des seuils techniques et l’oubli que toutes les classes de produits n’ont pas la même valeur économique marginale.• Trois jeux de données ont été soit analysés pour la première fois soit ré-analysés sous différentes hypothèses pour explorer l’importance de ces critiques.• Enfin, l’utilisation de seuils critiques comme critères de sélection très précoce est suggérée et discutée dans le cadre de l’amélioration intrinsèque de la qualité du bois juvénile.

A Test of the ‘Genetic Rescue’ Technique Using Bottlenecked Donor Populations of Drosophila melanogaster

The economics of short-rotation pulpwood plantations of Eucalyptus globulus as a coppice crop are influenced by stump survival and subsequent coppice growth rates. This study revealed significant genetic diversity in coppicing traits, both within and between subraces, following felling in a progeny trial after 9 years of growth. A total of 67% of trees coppiced after 14 months, but subraces varied from 43 to 73%. Heritabilities for coppice success (0.07) and subsequent growth (0.16–0.17) were low but statistically significant. Strong genetic correlation between presence/absence of coppice, the number of stems coppicing from the stump and modal coppice height, indicate that selection is possible by using the binary trait. The ability of a tree to coppice was genetically correlated with tree growth prior to felling (rg = 0.61) and with nursery-grown seedling traits, where large genetic differences were observed in the development of lignotubers. Coppicing was genetically correlated with the number of nodes with lignotubers (rg = 0.66) and seedling stem diameter at the cotyledonary node (rg = 0.91). These traits were uncorrelated with later age growth and with each other. The results suggest that coppicing is influenced by three independent mechanisms—lignotuber development, enlargement of the seedling stem at the cotyledonary node and vigorous growth—which enhance ability to survive catastrophic damage, and indicate that both lignotuber and coppice development can be altered by both natural and artificial selection.

Using a production approach to estimate economic weights for structural attributes of Pinus radiata wood

The long time frame for evaluating selection candidates is a major barrier to the deployment of genetic gain from tree breeding programs. This situation is compounded in wood quality studies by constraints on the number of sampled individuals when trees are older and larger. This paper documents the degree of genetic control and genetic association for wood quality traits in 18-month-old leaning Pinus radiata seedlings. Trees were separately assessed for basic density, green and dry acoustic velocity, and longitudinal and volumetric shrinkage in opposite and compression wood. Heritability estimates were low to moderate for both compression and opposite wood (ranging from 0.15 to 0.38). Estimated genetic correlations were very high in opposite wood, where green velocity displayed the highest correlations with both longitudinal (−0.89) and volumetric (−0.64) shrinkage, closely followed by dry velocity. These correlations were substantially lower for compression wood. The estimated correlations between compression and opposite wood characteristics were high for most traits except for longitudinal shrinkage. We suggest how these results could be used for very early screening for wood stiffness and dimensional stability. We propose that information on early genetic control of wood quality and the methodologies used to elicit it should be integrated in breeding and deployment programs.

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

Abstract• IntroductionGenetic testing is the slowest part of a breeding cycle. There is a growing interest in early wood quality screening methodologies. We hypothesized that subjecting 8-month-old radiata pine trees to mechanical perturbance induces reaction wood that permits isolating their likely corewood features.• MethodsFour clones were grown straight, tied at 45° from the vertical, or rocked on a purpose-built frame. Trees were assessed for growth, basic density, compression wood, number of resin canals, and three acoustic stiffness (MoE) measures with an ultrasonic timer.• ResultsThere were no significant differences between stem postures for growth. Both rocked and straight trees developed similar levels of compression wood (between 13% and 17%). Rocked trees had a significantly larger number of resin canals than straight trees. Rocked trees produced the lowest MoE for all acoustic assessments. Clonal rankings for MoE were consistent between standing tree and green stemwood MoE. There were small ranking differences for dry stemwood MoE. Clone F, which expresses low MoE as an adult tree, had consistently the lowest MoE assessments but also the highest basic density.• ConclusionThe observed differences in wood properties between clones make feasible their use for screening purposes at an early age.