Table 1 - uploaded by Luis Apiolaza
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Phenotypic descriptive statistics for green velocity, dry velocity, longitudinal shrinkage, volumetric shrinkage, and basic density
Source publication
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...
Contexts in source publication
Context 1
... phenotypic coefficients of variation were higher in opposite wood than in compression wood for all traits but basic density (Table 1). In opposite wood, longitudinal and volumetric shrinkage presented the largest variation, followed by green velocity, basic density, and dry velocity. ...
Context 2
... opposite wood, longitudinal and volumetric shrinkage presented the largest variation, followed by green velocity, basic density, and dry velocity. The variability ranking changed slightly in compression wood, from volumetric shrinkage through longitudinal shrinkage, basic density, and green velocity to dry velocity (Table 1). This change in ranking is attributed to physical and chemical differences in compression wood, including the large increase in basic density. ...
Context 3
... is important to remember that in genetic evaluation heritability acts as a shrinkage factor towards the trial mean. This means that the breeding value differences between trees are scaled to around 1/5 (for h 2 =0.2) to 1/3 (for h 2 = 0.3) of the phenotypic differences reported in Table 1. ...
Similar publications
Tree morphological characteristics, particularly straightness and lean, significantly influence the value of the commercial products that can be obtained. Despite this, they are not usually evaluated in timber field inventories because traditional techniques are labor-intensive and largely subjective, hence the use of these parameters is limited to...
Citations
... They were two-year old at the beginning of the experiment, which lasted for two growing seasons and was conducted in a greenhouse at UniversitéLaval, Quebec Canada. Knowing that the wood produced during the first years of a tree's life contains what is called "flexure wood" (Telewski, 1989), the seedlings were planted at an angle of 45°following a similar strategy to that used by Apiolaza et al. (2011) to ensure the production of normal wood. The use of this strategy made it possible to restrict the production of compression wood to only one side of the stems and normal wood otherwise, which was used for our measurements and analyses. ...
Drought frequency and intensity are projected to increase with climate change, thus amplifying stress on forest trees. Resilience to drought implicates physiological traits such as xylem conductivity and wood anatomical traits, which are related to growth and wood density. Integrating drought-stress response traits at the juvenile stage into breeding criteria could help promote the survival of planted seedlings under current and future climate and thus, improve plantation success. We assessed in greenhouse the influence of drought-induced stress on 600 two-year-old white spruce (Picea glauca) seedlings from 25 clonal lines after two consecutive growing seasons. Three levels of drought-induced stress were applied: control, moderate and severe. Seedlings were also planted at a 45° angle to clearly separate compression from normal wood. We looked at the phenotypic and genetic effects of drought stress on xylem specific hydraulic conductivity, lumen diameter, tracheid diameter and length, and the number of pits per tracheid in the normal wood. We detected no significant effects of drought stress except for tracheid length, which decreased with increasing drought stress. We found low to high estimates of trait heritability, which generally decreased with increasing drought stress. Genetic correlations were higher than phenotypic correlations for all treatments. Specific conductivity was genetically highly correlated positively with lumen diameter and tracheid length under all treatments. Tracheid length and diameter were always negatively correlated genetically, indicating a trade-off in resource allocation. Moderate to high genetic correlations sometimes in opposite direction were observed between physico-anatomical and productivity traits, also indicating trade-offs. A large variation was observed among clones for all physico-anatomical traits, but clonal ranks were generally stable between control and drought-induced treatments. Our results indicate the possibility of early screening of genetic material for desirable wood anatomical attributes under normal growing conditions, thus allowing to improve the drought resilience of young trees.
... However, the amount of wood available for evaluation was too small to be practical. Later work measured trees at 2 years of age (Apiolaza et al. 2011b), easily detecting variability and with enough material to simplify mass screening with fast and cheap techniques. The results were promising, but trees were planted directly at a site with more environmental variability than expected, introducing noise in the growth patterns and reducing selection accuracy. ...
... Moving to a progeny trial grown in bags improved the control of environmental noise compared to Apiolaza et al. (2011b), with which the Harewood trial has a substantial pedigree overlap. However, the earlier experiment only included the Seed Orchard population. ...
... The population differences observed in our trial mimic the significant wood properties differences between natural populations (provenances) of the same species, as observed in commonly planted temperate species like Pinus radiata (Burdon and Low 1992), Eucalyptus globulus (Dutkowski and Potts 1999;Apiolaza et al. 2005;Hamilton et al. 2007), Eucalyptus nitens (Purnell 1988), and Pseudotsuga menziesii (Lausberg et al. 1995). In all these examples trees were assessed between 1/4 and 1/2 of rotation length, but it is our expectation that provenance differences will be expressed very early on, as there is evidence of wood properties differences at 1 year of age, both between genotypes of the same species (Apiolaza et al. 2011b) and between species (Goncalves et al. 2018). ...
Trees in breeding programmes are often selected at 1/4–1/3 of rotation, called ‘early selection’, which is typically between 8 and 10 years in radiata pine. However, differences between populations and genotypes selected for either basic density or wood stiffness are already apparent at age 2. We report the application of very early screening techniques for wood properties in the New Zealand Radiata Pine Breeding Programme deployment populations. Approximately 3000 trees representing three populations with 92 families and 10 clones were grown in a common garden trial, leaning for 21 months to separate compression and opposite wood. The trees were harvested and analysis carried out separately by wood type. The trial showed the existence of large variability in wood properties at early age, in some cases similar to variability near rotation age, and moderate to high degree of genetic control ( $$0.35 \le h^2 \le 0.71$$ 0.35 ≤ h 2 ≤ 0.71 ). The genetic association between traits was strong, particularly between wood stiffness and longitudinal shrinkage ( $$-\,0.69$$ - 0.69 ) and between longitudinal and volumetric shrinkage (0.83), suggesting that improving stiffness would also have a strong effect on improving dimensional stability. Basic density was also associated with stiffness and shrinkage, but with lower predictive capacity. These results can be used for roguing deployment populations-which already contain superior growing trees-and quickly upgrade the wood quality of seeds and clones currently available to New Zealand forest growers. We discuss necessary modifications to turn this research work into operation to screen any new material before commercial release.
... year of age, both between genotypes of the same species(Apiolaza et al., 2011b) 338 and between species (Goncalves et al., 2018). 339 Implications 340 When presenting the idea of very early screening is common to face the question 341 "Where should we use it in a tree improvement programme?" ...
Trees in breeding programmes are often selected at 1/4-1/3 of rotation, called "early selection", which is typically between 8 and 10 years in radiata pine. However, differences between populations and genotypes selected for either basic density or wood stiffness are already apparent at age 2.
We report the application of very early screening techniques for wood properties in the New Zealand Radiata Pine Breeding Programme deployment populations. Approximately 3,000 trees representing three populations with 92 families and 10 clones were grown in a common garden trial, leaning for 21 months to separate compression and opposite wood. The trees were harvested and analysis carried outseparately by wood type.
The trial showed the existence of large variability in wood properties at early age, in some cases similar to variability near rotation age, and moderate to high degree of genetic control (0.35 <= h2 <= 0.71). The genetic association between traits was strong, particularly between wood stiffness and longitudinal shrinkage (-0.69) and between longitudinal and volumetric shrinkage (0.83), suggesting that improving stiffness would also have a strong effect on improving dimensional stability. Basic density was also associated to stiffness and shrinkage, but with lower predictive capacity.
These results can be used for roguing deployment populations—which already contain superior growing trees—and quickly upgrade the wood quality of seeds and clones currently available to New Zealand forest growers. We discuss necessary modifications to turn this research work into operations to screen any new material before commercial release.
... Furthermore, the obtained asymmetric credibility intervals for variance components, genetic parameters, and breeding values are a peculiarity of Bayesian inference, which make this approach notably informative (Mathew et al., 2012) and facilitate hypothesis testing. According to Apiolaza, Chauhan, and Walker (2011), asymmetric credibility intervals obtained based on posterior distribution make the conclusions more realistic than symmetric credibility intervals of frequentist statistics. Additionally, Bayesian inference allows for the evaluation of unbalanced experiments and study of highly complex statistical models (Bink et al., 2007). ...
The selection of superior sweet potato genotypes using Bayesian inference is an important strategy for genetic improvement. Sweet potatoes are of social and economic importance, being the material for ethanol production. The estimation of variance components and genetic parameters using Bayesian inference is more accurate than that using the frequently used statistical methodologies. This is because the former allows for using a priori knowledge from previous research. Therefore, the present study estimated genetic parameters and selection gains, predicted genetic values, and selected sweet potato genotypes using a Bayesian approach with a priori information. Root shape, soil insect resistance, and root and shoot productivity of 24 sweet potato genotypes were measured. Heritability, genotypic variation coefficient, residual variation coefficient, relative variation index, and selection gains direct, indirect and simultaneous were estimated, and the data were analyzed using Bayesian inference. Data from 11 experiments were used to obtain a priori information. Bayesian inference was a useful tool for decision-making, and significant genetic gains could be achieved with the selection of the evaluated genotypes. Root shape, soil insect resistance, commercial root productivity, and total root productivity showed higher heritability values. Clones UFVJM06, UFVJM40, UFVJM54, UFVJM09, and CAMBRAIA can be used as parents in future breeding programs.
... Wood produced during the first years of a tree's life contains so-called "flexure wood" (Telewski 1989), which has similar properties to compression wood. To ensure the production of normal wood even at an early age, the seedlings were planted at an angle of 45° following a similar strategy to that used by Apiolaza et al. (2011aApiolaza et al. ( , 2011b. Using this strategy, compression wood was produced on the lee side of the stem while normal wood was available for our analyses on the opposite side. ...
Forest plantations play an important role in maintaining a supply of high-quality timber from managed forest. With an expected increase in the prevalence of drought in some forested areas, climate change increases concerns about future seedling growth. A promising approach to promote the suitability of plantation seedlings to current and future climate would be to use variation in growth and wood traits of trees under drought as selection criteria in tree breeding programs, especially at a young stage when they are most vulnerable to drought. We evaluated the genetic control of the growth and wood density response of white spruce clonal seedlings submitted to various drought conditions in a greenhouse experiment. By varying the watering treatment of 600 two year-old seedlings from 25 clones, we simulated three levels of drought-induced stress during two growing seasons. Apical and radial growth decreased markedly as the intensity of drought increased, whereas wood density tended to increase. We also developed a woody biomass index composed of wood density and ring area, which was observed to decrease slightly with increasing drought. There was important variation in all traits among clones and heritability tended to decrease with the intensity and duration of drought-induced stress, mainly for wood density and radial growth. However, the heritability of apical growth tended to increase under drought conditions. Our results show that the response of young white spruce clones to drought is highly variable, and together with the significant levels of heritability noted, the results indicate that multi-trait genetic selection for drought stress response at a young age could represent a promising approach to increase resilience to drought.
... The estimated narrow-sense heritabilities (h 2 ) for axial resin canal density (h 2 = 0.33), relative area (h 2 = 0.31) and size (h 2 = 0.31) in 2-year-old P. radiata (Table 2) were comparable to estimated heritabilites for other wood properties in similarly aged P. radiata, including density and shrinkage (Apiolaza et al. 2011). These narrow-sense heritability values also fell close to the, typically higher, broad-sense heritabilities (H 2 ) for resin canal features in Picea abies. ...
Resin canal features are associated with significant economic losses to appearance grade Pinus radiata timber. This study investigated the variation in resin canal features in young, 2-year-old, P. radiata. Axial resin canal size, density and relative cross-sectional area were determined in twenty families and ten clones from images of microtomed sections, scanned with polarised light to highlight resin canals. Axial resin canal size was generally homogenous with a mean value estimate of 0.02 mm², and a coefficient of variation of ~ 10%. Estimated mean values for axial resin canal density and relative area were more variable (coefficients of variation ~ 30%) and lower for clones (0.69 canals/mm² and 1.13%, respectively) than for families (0.90 canals/mm² and 1.53%, respectively). Narrow-sense heritability (h²) estimates of the studied axial resin canal features in radiata pine at age 2-years-old were ~ 0.30. Modulus of elasticity and longitudinal shrinkage were moderately correlated with axial resin canal density and relative area, while basic density and volumetric shrinkage were independent of axial resin canal features. The study indicated that there could be potential for breeding P. radiata for resin canal features, with the aim to improve the grade yields of appearance grade products.
... They make this approach notably informative (Mathew et al. 2012) and facilitative of hypothesis testing. Asymmetric credibility intervals obtained using posterior distribution, and shown in Tables 1-6, make the conclusions more realistic than those based on symmetric confidence intervals of frequentist statistics (Apiolaza et al. 2011). Additionally, Bayesian inference Table 1. ...
Variance components must be obtained to estimate genetic parameters and predict breeding values. In studies which take many traits into account, it is reasonable to use the Bayesian approach for the estimation of genetic parameters. The main goal of the present research was not only to consider the genetic correlations of the examined traits, but above all to estimate unknown genetic parameters and to gain profits from the selection. Bayesian inference was also useful for the selection of the best maize varieties. It was applied to predict genetic values in the multi-traits linear model. Thirteen maize cultivars representing the traits of our interest were studied by means of Bayesian inference. The traits are the number of plants before harvest, the grain yield, the length of the ears, the mass of leaves and the number of ears. The experiment involved a randomised block design with four replications and ten plants per plot. The highest correlation estimates were found between the number of plants before harvest and the number of ears, jointly with the grain yield and the number of ears. Lower correlation estimates were found between the length of the ears and the number of ears as well as the grain yield and the length of the ears. The research confirms that the best varieties to be grown are: Clarica, NK Cooler, Drim and PR 39K13. The Bayesian approach proved to be useful in selection studies, which can further be used to improve the studied genotypes.
... Chauhan et al. (2013) performed resonance tests on young plants of Pinus radiata between 18 and 20 months of age and obtained a wave propagation velocity between 1260 and 1450 m·s −1 , with CV of 6.5% to 9.9%. Apiolaza et al. (2011b) using 18-month-old Pinus radiata obtained a velocity (in resonance test) of 1050 m·s −1 (CV = 9.7%) for opposite wood (side opposite to compression wood) and 1230 m·s −1 (CV = 7.28%) for compression wood. The differences between the two wood types (reaction and opposite) were identified by wave propagation tests, indicating the usefulness of the test even in very young plants (Apiolaza et al. 2011b). ...
... Apiolaza et al. (2011b) using 18-month-old Pinus radiata obtained a velocity (in resonance test) of 1050 m·s −1 (CV = 9.7%) for opposite wood (side opposite to compression wood) and 1230 m·s −1 (CV = 7.28%) for compression wood. The differences between the two wood types (reaction and opposite) were identified by wave propagation tests, indicating the usefulness of the test even in very young plants (Apiolaza et al. 2011b). Lindström et al. (2002) obtained velocities (ultrasound, stress wave, and resonance) between 1626 and 2193 m·s −1 in 48-month-old Pinus radiata. ...
Early selection of trees allows acceleration of genetic improvement, as well as processes related to forest management, to improve the quality of the wood produced; however, to reach this objective, it is necessary to know which parameters can be used as predictors of a tree’s aged condition. The objective of this research was to study parameters that are measurable in nursery seedlings and that could be used in prediction models of basic density (BDt), modulus of elasticity (EMt), and strength (fmt) of wood from trees. The tests were performed in 240 seedlings (3 and 6 months old) and in 52 trees (72 months old) from seven genetic units of two species: three Eucalyptus clones and four Pinus pinaster progenies. In the seedlings, measurements of longitudinal velocity of ultrasonic waves (VLs), basic density (BDs), height (Hs), diameter (Ds), strength (fts), and modulus of elasticity (Ets) in tension parallel to the grain were obtained. The EMt and fmt can be predicted by parameters obtained in seedlings of the same genetic unit. Thus, the use of these parameters, in association with others already used in selection programs, may increase the positive results of the early selection, with economic gains and time reductions in forest management.
... In addition, one can easily obtain complex distributions of functions of covariance components, like heritabilities, as a byproduct of the estimation process (Cappa and Cantet 2006). There are several examples of Bayesian applications in forest genetics, for example: univariate analysis of growth traits (Soria et al. 1998); multivariate analysis of growth traits (Cappa and Cantet 2006); and multivariate analysis of early wood properties (Apiolaza et al. 2011). ...
... New phenotyping techniques, like rapid growth strain-testing, increase selection intensity (as more trees are able to be assessed) and reduce selection time (as trees can be less than 2 years old when tested). As far as we are aware, variability for early wood properties is not smaller than at typical selection age and the degree of genetic control is also similar (Apiolaza et al. 2011). ...
Background
Narrow-sense heritabilities of the wood properties of 2-year-old Eucalyptus bosistoana F.Muell. were estimated from 623 stems. FindingsHeritability estimates were calculated for the following: growth strain (0.63), density (0.54), diameter (0.76), volumetric shrinkage (0.29), acoustic velocity (0.97) and stiffness (0.82). A modified version of the splitting test for detecting growth strain is described. The modified rapid-testing procedure resulted in left-censored growth strain data, so a Bayesian approach was implemented to reduce errors associated with censored data sets. Conclusions
Correlations between wood properties are presented and discussed, as well as trade-offs when shifting trait means by selective breeding.
... In this sense, a Bayesian framework allows fitting a large diversity of non-Gaussian data distributions and the calculation of transformed estimates (like heritability) is straightforward through the use of posterior distributions (de Villemereuil et al. 2013). Bayesian approaches have been used to estimate quantitative genetic parameters providing a better approximation to the realized distribution of the genetic parameters (Waldmann et al. 2008;Apiolaza et al. 2011;Cappa et al. 2012;Aparicio et al. 2015). The ability to summarize the accuracy around a point estimate through the posterior distribution is a clear advantage of this statistical framework compared with likelihood-based methods (Gianola and Fernando 1986;Shoemaker et al. 1999;Walsh 2001;Xu 2003;Waldmann et al. 2008). ...
... Bayesian methodologies have gained popularity in tree breeding due to the development of various statistical packages such as FlexQTLs (Bink et al. 2008, Fresnedo-Ramírez et al. 2016 and MCMCglmm (Hadfield 2010) for fitting Bayesianmixed models. The latter is publically available in R and tackles the difficulties in using general-purpose Bayesian inference software with pedigree information (Apiolaza et al. 2011). ...
Genetic components for economically important traits in walnut (Juglans regia) were estimated for the first time using historical pedigree and heirloom phenotypic data from the walnut breeding program at the University of California, Davis. The constructed pedigree is composed of ~ 15,000 individuals and is derived from current and historic phenotypic records dating back > 50 years and located across California. To predict the additive genetic values of individuals under selection, generalized linear mixed models (GLMM), implemented with MCMCglmm, were developed. Several repeatability models were established to obtain the best model and predict the genetic parameters for each trait. Repeatability for yield, harvest date, extra-light kernel color (ELKC), and lateral bearing were predicted at 0.82, 0.98, 0.63, and 0.96, respectively, and average narrow-sense heritabilities were 0.54, 0.77, 0.49, and 0.75, respectively. Each individual in the pedigree was ranked by its estimated breeding value (EBV). The genetic trend showed specific patterns for each trait, and real genetic improvement was found over time. The completed pedigree built here, the estimated breeding values, and the ranking of individuals according to their breeding values, can be used to guide future crossing designs in the walnut breeding program and future implementation of genomic selection methods in walnut.
