scholarly journals Genetic variation and parental performance under inbreeding for growth in Eucalyptus globulus

2010 ◽  
Vol 67 (6) ◽  
pp. 606-606 ◽  
Author(s):  
João Costa e Silva ◽  
Craig Hardner ◽  
Brad M. Potts
Keyword(s):  
Genetic Variation ◽  
Eucalyptus Globulus

scholarly journals Genetic resistance of Eucalyptus globulus to autumn gum moth defoliation and the role of cuticular waxes

2002 ◽  
Vol 32 (11) ◽  
pp. 1961-1969 ◽  
Author(s):  
T H Jones ◽  
B M Potts ◽  
R E Vaillancourt ◽  
N W Davies
Keyword(s):  
Genetic Variation ◽  
Eucalyptus Globulus ◽  
Field Trial ◽  
Genetic Resistance ◽  
Cuticular Wax ◽  
Wax Esters ◽  
Broad Sense ◽  
Broad Sense Heritability ◽  
Cuticular Waxes

This study investigated the association between resistance of Eucalyptus globulus Labill. to autumn gum moth (Mnesempala privata Guenée) defoliation and cuticular wax compounds. In a field trial consisting of clonally replicated F2 families of E. globulus, situated in Tasmania, Australia, significant genetic variation in resistance was detected in two of three F2 families. The broad-sense heritability for defoliation within families ranged from 0.24 to 0.33. The 15 most resistant and the 15 most susceptible genotypes within each variable family were compared for their relative levels of 26 cuticular wax compounds. While no significant correlation between resistance and total wax yield estimates was found, significant differences were detected between resistant and susceptible classes in the relative quantities of several aliphatic phenylethyl and benzyl wax esters within both families. This association does not appear to be a response induced by defoliation. The broad-sense heritabilities of the variation in these compounds were high (0.82–0.94). Our findings suggest that these wax compounds are a mechanism of genetic resistance to autumn gum moth in E. globulus.

The genetic variation in the timing of heteroblastic transition in Eucalyptus globulus is stable across environments

2011 ◽  
Vol 59 (2) ◽  
pp. 170 ◽  
Author(s):  
M. G. Hamilton ◽  
P. A. Tilyard ◽  
D. R. Williams ◽  
R. E. Vaillancourt ◽  
T. J. Wardlaw ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Phase Change ◽  
Eucalyptus Globulus ◽  
Developmental Change ◽  
Genetic Correlations ◽  
Genotype By Environment Interaction ◽  
Environment Interaction ◽  
Narrow Sense Heritability ◽  
Genotype By Environment ◽  
Analyse Data

Eucalyptus globulus is one of the best known examples of a heteroblastic plant. It exhibits a dramatic phase change from distinctive juvenile to adult leaves, but the timing of this transition varies markedly. We examined the genetic variation in the timing of heteroblastic transition using five large open-pollinated progeny trials established in north-western Tasmania. We used univariate and multi-variate mixed models to analyse data on the presence/absence of adult or intermediate foliage at age 2 years from a total of 14 860 trees across five trials, as well as height to heteroblastic phase change from one trial. Up to 566 families and 15 geographic subraces of E. globulus were represented in the trials. The timing of the heteroblastic transition was genetically variable and under strong genetic control at the subrace and within-subrace level, with single-trial narrow-sense heritability estimates for the binary trait averaging 0.50 (range 0.44–0.65). The degree of quantitative trait differentiation in the timing of heteroblastic transition among subraces, as measured by QST, exceeded the published level of neutral molecular marker (FST) differentiation in all cases, arguing that diversifying selection has contributed to shaping broad-scale patterns of genetic differentiation. Most inter-trial genetic correlations were close to one at the subrace and additive genetic levels, indicating that the genetic variation in this important developmental change is expressed in a stable manner and that genotype-by-environment interaction is minimal across the environments studied.

Genetic variation for resistance to Mycosphaerella leaf disease and Eucalyptus rust on Eucalyptus globulus in Uruguay

2013 ◽  
Vol 43 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Gustavo Balmelli ◽  
Sofía Simeto ◽  
Virginia Marroni ◽  
Nora Altier ◽  
Julio J. Diez
Keyword(s):  
Genetic Variation ◽  
Eucalyptus Globulus ◽  
Leaf Disease ◽  
Eucalyptus Rust ◽  
Mycosphaerella Leaf Disease

scholarly journals Assessing genetic variation to improve stem straightness in Eucalyptus globulus

2013 ◽  
Vol 70 (5) ◽  
pp. 461-470 ◽  
Author(s):  
David P. Blackburn ◽  
Matthew G. Hamilton ◽  
Chris E. Harwood ◽  
Thomas G. Baker ◽  
Brad M. Potts
Keyword(s):  
Genetic Variation ◽  
Eucalyptus Globulus ◽  
Stem Straightness

Genetic control of Eucalyptus globulus harvest traits

2015 ◽  
Vol 45 (6) ◽  
pp. 615-624 ◽  
Author(s):  
Matthew G. Hamilton ◽  
Mauricio Acuna ◽  
John C. Wiedemann ◽  
Rick Mitchell ◽  
David J. Pilbeam ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Eucalyptus Globulus ◽  
Genetic Correlations ◽  
Basal Area ◽  
Field Trials ◽  
Slight Reduction ◽  
Growth And Survival ◽  
Short Rotation ◽  
Stem Straightness ◽  
Tree Genetics

The cost of harvesting short-rotation plantation eucalypts can be in excess of AU$2500·ha−1. Despite this high cost, the extent to which harvesting productivity is affected by tree genetics is not well understood. We address this issue in a study of two 10-year-old genetic field trials of Eucalyptus globulus Labill. in Australia. Standing-tree traits analysed were survival, diameter at breast height, basal area, and stem straightness and forking. Harvest traits analysed were volume, time, and productivity. Genetic group and within-group genetic variation (additive and dominance), stand-level family variation, phenotypic and genetic correlations, and the effects of inbreeding were estimated for these traits. The different scenarios studied showed that plantation harvest productivity was affected by tree genetics to some degree but was mainly affected through positive covariation with stem diameter. Harvest productivity is thus unlikely to have been adversely affected by past selection. Although no significant additive or dominance genetic variation in stem forking or straightness was detected, weak phenotypic correlations were consistent with harvest productivity being higher in straighter trees with no forking. High inbreeding depression was evident for growth and survival; however, in open-pollinated progeny, this resulted in only a slight reduction in harvest productivity (5.5%) compared with out-crossed progeny.

scholarly journals The Effects of Drying Temperature and Method of Assessment on the Expression of Genetic Variation in Gross Shrinkage of Eucalyptus globulus Wood Samples

2009 ◽  
Vol 58 (1-6) ◽  
pp. 252-261 ◽  
Author(s):  
Matthew G. Hamilton ◽  
C. E. Harwood ◽  
B. M. Potts
Keyword(s):  
Genetic Variation ◽  
Eucalyptus Globulus ◽  
Genetic Correlations ◽  
Basic Density ◽  
Strongly Correlated ◽  
Drying Temperature ◽  
Additive Genetic Variation ◽  
Tangential Shrinkage ◽  
Drying Treatment ◽  
Method Of Assessment

Abstract Genetic variation in wood-sample gross shrinkage and basic density was examined in a Eucalyptus globulus base population trial growing in Tasmania, Australia. Gross shrinkage, which includes all components of shrinkage including collapse, was assessed in four ways (calliper- and visually-assessed tangential shrinkage, volumetric shrinkage and radial shrinkage) on samples dried at three temperatures (22°C, 60°C and 105°C). Significant differences between subraces were observed using all measures of gross shrinkage for two or more of the three drying treatments. Furthermore, significant additive genetic variation within subraces was observed in calliper- and visually-assessed gross shrinkage under two or more of the drying treatments, with narrowsense heritabilities greater than or equal to 0.35. There was no obvious trend in heritabilities or coefficients of additive genetic variation with drying temperature. Under the 105°C drying treatment, subrace correlations among calliper-, visually- and volume-assessed gross shrinkage were positive and very strong (≥ 0.97), while these measures were less strongly correlated with radial gross shrinkage at the subrace level (≤ 0.77). Withinsubrace genetic correlations among the first three measures were also strongly positive (≥ 0.95). These high genetic correlations suggest that different drying regimes and the calliper, visual and volume methods of assessment could be used interchangeably to select for reduced tangential gross shrinkage. Estimated subrace and genetic correlations between basic density and measures of gross shrinkage were universally negative (i.e. favourable), although not all were significantly different to zero.

scholarly journals Maternal and carryover effects on early growth of Eucalyptus globulus

2003 ◽  
Vol 33 (11) ◽  
pp. 2108-2115 ◽  
Author(s):  
Gustavo A Lopez ◽  
Bradley M Potts ◽  
René E Vaillancourt ◽  
Luis A Apiolaza
Keyword(s):  
Genetic Variation ◽  
Eucalyptus Globulus ◽  
Genetic Parameters ◽  
Germination Rate ◽  
Seed Mass ◽  
Field Trials ◽  
Early Growth ◽  
Reciprocal Effects ◽  
Carryover Effects ◽  
Reciprocal Differences

Maternal and nonmaternal reciprocal effects were compared with nuclear genetic and carryover effects using a diallel mating amongst eight Eucalyptus globulus Labill. wild parents from northeastern and southern Tasmania races. Seed mass exhibited a significant maternal effect, increasing seed germinative capacity but not germination rate. After accounting for variation in seed mass, both germinative capacity and germination rate exhibited significant reciprocal effects, but these were non maternal in origin. Rapid germination and large seeds resulted in significantly larger seedlings in the nursery, but these carryover effects diminished with age. In contrast, the expression of genetic effects increased with age. Significant additive genetic variation was detected for growth by age 3 years and significant reciprocal differences were detected at the race level after 2 years in field trials. If common, such reciprocal effects could bias genetic parameters and impact on the choice of cross-direction in deployment programs. Failure to account for carryover effects in genetic analyses may inflate estimates of genetic variation for growth during early stages of the life cycle.

scholarly journals Genetic Variation of Physical and Chemical Wood Properties of Eucalyptus globulus

2005 ◽  
Vol 54 (1-6) ◽  
pp. 160-166 ◽  
Author(s):  
L. A. Apiolaza ◽  
C. A. Raymond ◽  
B. J. Yeo
Keyword(s):  
Genetic Variation ◽  
Eucalyptus Globulus ◽  
Genetic Correlations ◽  
Fibre Length ◽  
Microfibril Angle ◽  
Basic Density ◽  
Wood Properties ◽  
Pulp Yield ◽  
Cellulose Content ◽  
Wood Processing

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 ($862.04), Western Otways ($657.80) and Strzelecki Foothills ($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 $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.

Geographic Patterns of Genetic Variation in Eucalyptus globulus ssp. globulus and a Revised Racial Classification

1999 ◽  
Vol 47 (2) ◽  
pp. 237 ◽  
Author(s):  
G. W. Dutkowski ◽  
B. M. Potts
Keyword(s):  
Genetic Variation ◽  
Eucalyptus Globulus ◽  
Multivariate Analyses ◽  
Basic Density ◽  
Field Trials ◽  
Racial Classification ◽  
Regional Patterns ◽  
Growth And Survival ◽  
Geographic Patterns ◽  
Quantitative Genetic

The geographic patterns of genetic variation in a wide variety of quantitative traits were studied in Eucalyptus globulus ssp. globulus and its intergrades, leading to a revised racial classification. The analysis was based on 35 traits assessed in five field trials in northern Tasmania from approximately 500 open-pollinated families, encompassing 49 collection localities in native stands. There were significant differences between the collection localities for most traits. While growth and survival traits exhibited weak spatial structuring, there were clear regional patterns in bark thickness, wood basic density, flowering precocity and some aspects of juvenile leaf morphology. There were a number of significant correlations between trait locality means, but few simple correlations between the regional patterns observed and climate. Multivariate analyses indicated that the localities could be effectively amalgamated into larger, geographically concordant races. A hierarchy of five major groupings of 13 races and 20 subraces is proposed to account for most of the quantitative genetic variation while allowing for outliers and intermediate populations. Some areas of the distribution may need further sampling to more accurately elucidate their racial affinities, especially those with traits of high economic importance.

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