Assessing genetic variation to improve stem straightness in Eucalyptus globulus

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.

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Genetic variation in growth, stem straightness and branch thickness in clonal trials of Acacia auriculiformis at three contrasting sites in Vietnam

Forest Ecology and Management ◽

10.1016/j.foreco.2007.09.017 ◽

2008 ◽

Vol 255 (1) ◽

pp. 156-167 ◽

Cited By ~ 37

Author(s):

Phi Hong Hai ◽

G. Jansson ◽

C. Harwood ◽

B. Hannrup ◽

Ha Huy Thinh

Keyword(s):

Genetic Variation ◽

Acacia Auriculiformis ◽

Stem Straightness

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Genetic variation in Eucalyptus camaldulensis Dehnh. for growth and stem straightness in a provenance–family trial on saltland in Pakistan

Forest Ecology and Management ◽

10.1016/s0378-1127(02)00230-x ◽

2003 ◽

Vol 176 (1-3) ◽

pp. 405-416 ◽

Cited By ~ 13

Author(s):

K Mahmood ◽

N.E Marcar ◽

M.H Naqvi ◽

R.J Arnold ◽

D.F Crawford ◽

...

Keyword(s):

Genetic Variation ◽

Eucalyptus Camaldulensis ◽

Stem Straightness ◽

Eucalyptus Camaldulensis Dehnh

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

Canadian Journal of Forest Research ◽

10.1139/x02-118 ◽

2002 ◽

Vol 32 (11) ◽

pp. 1961-1969 ◽

Cited By ~ 39

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 (0.820.94). Our findings suggest that these wax compounds are a mechanism of genetic resistance to autumn gum moth in E. globulus.

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

Australian Journal of Botany ◽

10.1071/bt10313 ◽

2011 ◽

Vol 59 (2) ◽

pp. 170 ◽

Cited By ~ 17

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.

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Genomic Prediction of Growth and Stem Quality Traits in Eucalyptus globulus Labill. at Its Southernmost Distribution Limit in Chile

Forests ◽

10.3390/f9120779 ◽

2018 ◽

Vol 9 (12) ◽

pp. 779 ◽

Cited By ~ 5

Author(s):

Paulina Ballesta ◽

Nicolle Serra ◽

Fernando Guerra ◽

Rodrigo Hasbún ◽

Freddy Mora

Keyword(s):

Genomic Prediction ◽

Eucalyptus Globulus ◽

Growth Traits ◽

Principal Component ◽

Local Economy ◽

Range Limit ◽

Distribution Limit ◽

Genome Wide ◽

A Genome ◽

Stem Straightness

The present study was undertaken to examine the ability of different genomic selection (GS) models to predict growth traits (diameter at breast height, tree height and wood volume), stem straightness and branching quality of Eucalyptus globulus Labill. trees using a genome-wide Single Nucleotide Polymorphism (SNP) chip (60 K), in one of the southernmost progeny trials of the species, close to its southern distribution limit in Chile. The GS methods examined were Ridge Regression-BLUP (RRBLUP), Bayes-A, Bayes-B, Bayesian least absolute shrinkage and selection operator (BLASSO), principal component regression (PCR), supervised PCR and a variant of the RRBLUP method that involves the previous selection of predictor variables (RRBLUP-B). RRBLUP-B and supervised PCR models presented the greatest predictive ability (PA), followed by the PCR method, for most of the traits studied. The highest PA was obtained for the branching quality (~0.7). For the growth traits, the maximum values of PA varied from 0.43 to 0.54, while for stem straightness, the maximum value of PA reached 0.62 (supervised PCR). The study population presented a more extended linkage disequilibrium (LD) than other populations of E. globulus previously studied. The genome-wide LD decayed rapidly within 0.76 Mbp (threshold value of r2 = 0.1). The average LD on all chromosomes was r2 = 0.09. In addition, the 0.15% of total pairs of linked SNPs were in a complete LD (r2 = 1), and the 3% had an r2 value >0.5. Genomic prediction, which is based on the reduction in dimensionality and variable selection may be a promising method, considering the early growth of the trees and the low-to-moderate values of heritability found in the traits evaluated. These findings provide new understanding of how develop novel breeding strategies for tree improvement of E. globulus at its southernmost range limit in Chile, which could represent new opportunities for forest planting that can benefit the local economy.

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

Annals of Forest Science ◽

10.1051/forest/2010019 ◽

2010 ◽

Vol 67 (6) ◽

pp. 606-606 ◽

Cited By ~ 18

Author(s):

João Costa e Silva ◽

Craig Hardner ◽

Brad M. Potts

Keyword(s):

Genetic Variation ◽

Eucalyptus Globulus

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Genetic variation in growth and stem straightness inEucalyptus salignatrials in Fujian

Australian Forestry ◽

10.1080/00049158.2012.10676398 ◽

2012 ◽

Vol 75 (3) ◽

pp. 163-174 ◽

Cited By ~ 2

Author(s):

Lan Hesheng ◽

Huang Xiumei ◽

Luo Jianzhong ◽

Roger J. Arnold

Keyword(s):

Genetic Variation ◽

Stem Straightness

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Single- and multiple-trait index selection efficiencies in Fraser fir Christmas trees

Canadian Journal of Forest Research ◽

10.1139/x94-192 ◽

1994 ◽

Vol 24 (7) ◽

pp. 1487-1494 ◽

Cited By ~ 2

Author(s):

R.J. Arnold ◽

F.E. Bridgwater ◽

J.B. Jett

Keyword(s):

Genetic Variation ◽

Selection Process ◽

Selection Strategy ◽

Index Selection ◽

Family Selection ◽

Multiple Trait ◽

Individual Values ◽

Source Selection ◽

Stem Straightness ◽

Initial Source

Selection methods for Abiesfraseri (Pursh) Poir. for Christmas tree wholesale value were evaluated based on parameters from the species' first genetic field test. For single-trait individual selection, combined individual plus family selection at half rotation age (4 years) on total height (HT4) gave the greatest estimated full rotation (8-year) retail value (VALUE) gain of 24.3%. The best 8-year trait, crown diameter, resulted in a gain of only 22.4%. Incorporation of family mean information together with individual values in the selection process was important in maximizing gains. Only 8-year stem straightness (STR8) had unfavorable genetic and phenotypic correlations with other traits. With multitrait combined optimum index selection, use of Kempthorne restrictions to prevent adverse change in this trait seriously limited gains in other 8-year traits. Severity of this limitation increased for younger age indices, and for those with fewer traits. Unrestricted combined optimum indices offered substantial VALUE gain advantages and only small decreases in STR8. Initial selection among seed sources also increased VALUE gain, despite decreasing the effective additive genetic variation. VALUE gains through initial source selection exceeded gain reductions from the genetic variation decreases. The optimum selection strategy, with 30.5% VALUE gain, involved initial source selection followed by unrestricted combined optimum index selection on HT4, and 4-year density. Though slightly below the maximum, this strategy would provide substantial economic and technical advantage in conducting field tests.

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