Stability of quantitative trait loci for growth and wood properties across multiple pedigrees and environments in <i><scp>E</scp>ucalyptus globulus</i>

Freeman, Jules S.; Potts, Brad M.; Downes, Geoffrey M.; Pilbeam, David J.; Thavamanikumar, Saravanan; Vaillancourt, René E.

doi:10.1111/nph.12237

Cited by 60 publications

(68 citation statements)

References 78 publications

(136 reference statements)

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“…QTL validation across families was also investigated for wood quality and growth traits. In Eucalyptus, out of 13 QTLs for wood properties, only three were validated in a second family (Thamarus et al 2004); and more recently, only 16 % of the 98 QTLs mapped for growth and wood traits were detected when moving to different genetic backgrounds (Freeman et al 2013). Similar results have been reported for conifers where only a small proportion of QTLs could be detected in unrelated families for different traits (Brown et al 2003;Devey et al 2004;Pelgas et al 2011).…”

Section: Resultssupporting

confidence: 60%

Genetic mapping and validation of QTLs associated with resistance to Calonectria leaf blight caused by Calonectria pteridis in Eucalyptus

Zarpelon

Guimarães

Faria

et al. 2014

Tree Genetics & Genomes

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Calonectria leaf blight (CLB) caused byCalonectria pteridis is one of the main leaf diseases in Brazilian Eucalyptus plantations in warm climates with prolonged periods of rain. The main symptoms are leaf spots followed by intense defoliation in highly susceptible plants.Exploiting the existing inter-and intraspecific variability for defoliation is the best option to control this disease. Nevertheless, nothing is known about the genetic architecture of resistance to CLB in Eucalyptus. We built microsatellitebased genetic maps for E. urophylla × E. camaldulensis (EU11×EC06) F1 family of 89 plants. Four or five clonal replicates per individual offspring were clonally propagated, totalling 445 plants which were phenotyped for defoliation in the basal third of the branches at 30 days following controlled inoculation with a single-spore isolate. Genetic mapping was performed using a pseudo-testcross, and QTLs detected using composite interval mapping. Five QTLs were detected for resistance to CLB; of them, only one could be validated in two unrelated pedigrees, and its effect was conservatively estimated as controlling between 5 and 10 % of the phenotypic variation when the bias derived from the limited size of the mapping population was taken into account. This work provides a starting point for future studies of the genetics of resistance to CLB, and adds further evidence to the challenge of ascertaining the effects of QTLs detected in a single biparental background across unrelated families.

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Section: Resultssupporting

confidence: 60%

Genetic mapping and validation of QTLs associated with resistance to Calonectria leaf blight caused by Calonectria pteridis in Eucalyptus

Zarpelon

Guimarães

Faria

et al. 2014

Tree Genetics & Genomes

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“…The strength of NIR calibrations for wood density can be variable (Schimleck et al 2001a(Schimleck et al , 2001bSchimleck 2008). NIR is increasingly used for routine prediction of KPY and CC and other wood chemical properties, typically from ground woodmeal samples Stackpole et al 2010;Downes et al 2011;Dillon et al 2012;Freeman et al 2013) and more recently from scanning of radial wood samples . Here, we have obtained KPY and CC data from NIR scanning of samples prepared for SilviScan analysis.…”

Section: Nir Prediction Of Physical Wood Propertiesmentioning

confidence: 99%

Wood properties ofEucalyptus globulusat three sites in Western Australia: effects of fertiliser and plantation stocking

Downes

Harwood

Washusen

et al. 2014

Australian Forestry

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Wood properties of 10-year-old trees in Eucalyptus globulus plantations at three sites in Western Australia were examined. Silvicultural treatments applied at age two years were stocking (unthinned, 1250 stems ha -1 ; thinned to 600 stems ha -1 or 300 stems ha -1 ) and nitrogen fertiliser application (0 or 250 kg ha -1 elemental nitrogen) in factorial combination. The three sites differed markedly in their annual rainfall (620-1100 mm), openpan evaporation and soil water-holding capacity. Wood cores were collected at breast height from a total of 263 trees (~15 trees for each site-by-treatment combination), and radial samples prepared for analysis by SilviScan to produce radial profiles of air-dry density and microfibril angle (MFA) and modulus of elasticity (MOE), and by radial near infrared (NIR) surface scanning to produce radial profiles of NIR-predicted Kraft pulp yield (KPY) and cellulose content (CC). Sampling interval was 0.025 mm for density and 5 mm for the other properties. For wood property mean values (i.e. wood property averages of each pith-to-cambium sample), sites differed significantly only in airdry density. The Boyup Brook site, which had low annual rainfall, the lowest climate wetness index and soil water-storage capacity and the slowest diameter growth, had the highest mean wood density (648 kg m -3 ), while Scott River, with the highest rainfall, had mean density that was 10% lower. The Wellstead site (low rainfall but highest soil water-storage capacity) was intermediate for density. The only other significant differences for mean wood properties were caused by fertiliser addition, which reduced NIR-predicted KPY from 54.6% (without fertiliser) to 54.1% and predicted CC from 43.7% to 43.1%. Clear radial trends were evident for all wood properties. Density, MOE, KPY and CC all increased from pith to the cambium, while MFA declined. From the innermost (pith) 10% to the outermost (cambial) 10% of the radius, density increased on average by 21%, MOE by 103%, KPY by 9% and cellulose by 11%, while MFA declined by 47%. NIR calibrations developed using the SilviScan and NIR spectral data explained 71% of variance in MOE for an independent set of radial wood samples of E. globulus from Victoria, but less than 50% of variance for density and MFA. Implications for paper pulp and veneer manufacture are briefly considered.

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“…This problem is especially serious in the validation of QTL due to the high likelihood that effects considered to be significant in one population are not counted as significant in another even if they were true in both (Dillon et al 2012;Freeman et al 2013). For some traits (e.g., growth), where most effect sizes appear to be small and heritability is low, a huge effort would be required in order to capture most of the heritability with very large mapping populations replicated in multiple sites (Fig.…”

Section: Issues Of Current and Future Studiesmentioning

confidence: 99%

Estimation of number and size of QTL effects in forest tree traits

Hall

Hallingbäck

2016

Tree Genetics & Genomes

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Mapping the genetic architecture of forest tree traits is important in order to understand the evolutionary forces that have shaped these traits and to facilitate the development of genomic-based breeding strategies. We examined the number, size, and distribution of allelic effects influencing eight types of traits using 30 published mapping studies (linkage and association mapping) in forest trees. The sizes of allelic effects, measured as the phenotypic variance explained, generally showed a severely right-skewed distribution. We estimated the numbers of underlying causal effects (n qtl ) for different trait categories by improving a method previously developed by Otto and Jones (Genetics 156:2093(Genetics 156: -2107(Genetics 156: , 2000. Estimates of n qtl based on association mapping studies were generally higher (median at 643) than those based on linkage mapping (median at 33). Comparisons with simulated linkage and association mapping data suggested that the lower n qtl estimates for the linkage mapping studies could partly be explained by fewer causal loci segregating within the full-sib family populations normally used, but also by the cosegregation of causal loci due to limited recombination. Disease resistance estimates based on linkage mapping studies had the lowest median of four underlying effects, while growth traits based on association mapping had about 580 effects. Theoretically, the capture of 50% of the genetic variation would thus require a population size of about 200 for disease resistance in linkage mapping, while growth traits in association mapping would require about 25,000. The adequacy and reliability of the improved method was successfully verified by applying it to the simulated data.

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Stability of quantitative trait loci for growth and wood properties across multiple pedigrees and environments in Eucalyptus globulus

Cited by 60 publications

References 78 publications

Genetic mapping and validation of QTLs associated with resistance to Calonectria leaf blight caused by Calonectria pteridis in Eucalyptus

Genetic mapping and validation of QTLs associated with resistance to Calonectria leaf blight caused by Calonectria pteridis in Eucalyptus

Wood properties ofEucalyptus globulusat three sites in Western Australia: effects of fertiliser and plantation stocking

Estimation of number and size of QTL effects in forest tree traits

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