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- Arkitektur & teknik 2020/21, Årskurs 3, et al.
(author)
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Resedagbok Schweiz augusti 2021
- 2021
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Other publication (other academic/artistic)abstract
- Arkitektur och tekniks årliga studieresa till Schweiz är på många sätt unik. Vi transporterar oss själva genom det vackra alplandskapet och besöker några av landets vackraste broar och byggnader. De vilda bergsmassiven och den förfinade byggnadskulturen väver sig in i varandra under hela vår magiska arkitektursafari. Resan i augusti 2021 blev nästan ett år försenad på grund av pandemin. I stället för en förberedelse av studierna i årskurs 3 blev det en festlig avslutning på kandidattiden på Chalmers. Vid sidan om våra gängse besöksmål, från Robert Maillarts och Jürg Conzetts konstruktioner till Le Corbusier och Peter Zumthors arkitektur, hade vi den här resan ett särskilt fokus på materialen lera, kalk, sten och cement, och på restaurering av broar och byggnader i dessa material.
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| 3. |
- Baison, J., et al.
(author)
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Genetic control of tracheid properties in Norway spruce wood
- 2020
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In: Scientific Reports. - : Nature Research. - 2045-2322. ; 10:1
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Journal article (peer-reviewed)abstract
- Through the use of genome-wide association studies (GWAS) mapping it is possible to establish the genetic basis of phenotypic trait variation. Our GWAS study presents the first such effort in Norway spruce (Picea abies (L). Karst.) for the traits related to wood tracheid characteristics. The study employed an exome capture genotyping approach that generated 178 101 Single Nucleotide Polymorphisms (SNPs) from 40 018 probes within a population of 517 Norway spruce mother trees. We applied a least absolute shrinkage and selection operator (LASSO) based association mapping method using a functional multi-locus mapping approach, with a stability selection probability method as the hypothesis testing approach to determine significant Quantitative Trait Loci (QTLs). The analysis has provided 30 significant associations, the majority of which show specific expression in wood-forming tissues or high ubiquitous expression, potentially controlling tracheids dimensions, their cell wall thickness and microfibril angle. Among the most promising candidates based on our results and prior information for other species are: Picea abies BIG GRAIN 2 (PabBG2) with a predicted function in auxin transport and sensitivity, and MA_373300g0010 encoding a protein similar to wall-associated receptor kinases, which were both associated with cell wall thickness. The results demonstrate feasibility of GWAS to identify novel candidate genes controlling industrially-relevant tracheid traits in Norway spruce. © 2020, The Author(s).
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| 4. |
- Baison, John, et al.
(author)
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Genome-Wide Association Study (GWAS) identified novel candidate loci affecting wood formation in Norway spruce
- 2019
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In: The Plant Journal. - : Wiley. - 0960-7412 .- 1365-313X. ; 100:1, s. 83-100
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Journal article (peer-reviewed)abstract
- Norway spruce is a boreal forest tree species of significant ecological and economic importance. Hence there is a strong imperative to dissect the genetics underlying important wood quality traits in the species. We performed a functional Genome-Wide Association Study (GWAS) of 17 wood traits in Norway spruce using 178101 single-nucleotide polymorphisms (SNPs) generated from exome genotyping of 517 mother trees. The wood traits were defined using functional modelling of wood properties across annual growth rings.We applied a LASSO based association mapping method using a functional multi-locus mapping approach that utilizes latent traits, with a stability selection probability method as the hypothesis testing approach to determine significant Quantitative Trait Loci (QTLs). The analysis provided 52 significant SNPs from 39 candidate genes, including genes previously implicated in wood formation and tree growth in spruce and other species. Our study represents a multi-locus GWAS for complex wood traits in Norway spruce. The results advance our understanding of the genetics influencing wood traits and identifies candidate genes for future functional studies.
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| 5. |
- Baison, John, et al.
(author)
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Genome-wide association study identified novel candidate loci affecting wood formation in Norway spruce
- 2019
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In: The Plant Journal. - : John Wiley & Sons. - 0960-7412 .- 1365-313X. ; 100:1, s. 83-100
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Journal article (peer-reviewed)abstract
- Norway spruce is a boreal forest tree species of significant ecological and economic importance. Hence there is a strong imperative to dissect the genetics underlying important wood quality traits in the species. We performed a functional genome-wide association study (GWAS) of 17 wood traits in Norway spruce using 178 101 single nucleotide polymorphisms (SNPs) generated from exome genotyping of 517 mother trees. The wood traits were defined using functional modelling of wood properties across annual growth rings. We applied a Least Absolute Shrinkage and Selection Operator (LASSO-based) association mapping method using a functional multilocus mapping approach that utilizes latent traits, with a stability selection probability method as the hypothesis testing approach to determine a significant quantitative trait locus. The analysis provided 52 significant SNPs from 39 candidate genes, including genes previously implicated in wood formation and tree growth in spruce and other species. Our study represents a multilocus GWAS for complex wood traits in Norway spruce. The results advance our understanding of the genetics influencing wood traits and identifies candidate genes for future functional studies.
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| 7. |
- Chen, Zhiqiang, et al.
(author)
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Inheritance of growth and solid wood quality traits in a large Norway spruce population tested at two locations in southern Sweden
- 2014
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In: Tree Genetics & Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 10:5, s. 1291-1303
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Journal article (peer-reviewed)abstract
- Unfavorable genetic correlations between growth and wood quality traits are one of the biggest challenges in advanced conifer breeding programs. To examine and deal with such correlation, increment cores were sampled at breast height from 5,618 trees in 524 open-pollinated families in two 21-year-old Norway spruce progeny trials in southern Sweden, and age trends of genetic variation, genetic correlation, and efficiency of selection were investigated. Wood quality traits were measured on 12-mm increment cores using SilviScan. Heritability was moderate (~0.4-0.5) for wood density and modulus of elasticity (MOE) but low (~0.2) for microfibril angle (MFA). Different age trends were observed for wood density, MFA, and MOE, and the lower heritability of MFA relative to wood density and MOE in Norway spruce contrasted with general trends of the three wood quality traits in pine. Genetic correlations among growth, wood density, MFA, and MOE increased to a considerably high value from pith to bark with unfavorable genetic correlations (−0.6 between growth and wood density, −0.74 between growth and MOE). Age-age genetic correlations reached 0.9 after ring 4 for diameter at breast height (DBH), wood density, MFA, and MOE traits. Early selections at ring 10 for diameter and at ring 6 or 7 for wood quality traits had similar effectiveness as selection conducted at reference ring 15. Selection based on diameter alone produced 19.0 % genetic gain in diameter but resulted in 4.8 % decrease in wood density, 9.4 % decrease in MOE, and 8.0 % increase in MFA. Index selection with a restriction of no change in wood density, MOE, and MFA, respectively, produced relatively lower genetic gains in diameter (16.4, 12.2, and 14.1 %, respectively), indicating such index selection could be implemented to maintain current wood density. Index selection using economic weights is, however, recommended for maximum economic efficiency
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| 8. |
- Chen, Zhi-Qiang, et al.
(author)
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Estimating solid wood properties using Pilodyn and acoustic velocity on standing trees of Norway spruce
- 2015
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In: Annals of Forest Science. - : Springer Science and Business Media LLC. - 1286-4560 .- 1297-966X. ; 72:4, s. 499-508
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Journal article (peer-reviewed)abstract
- Key message: Strong genetic correlations were observed between Pilodyn measurement and wood density, and between acoustic velocity and MFA. Combination of Pilodyn penetration and acoustic velocity measurements from standing trees can provide reliable prediction of stiffness of Norway spruce for breeding selection.Context: Traditional methods for the estimation of solid wood quality traits of standing tree such as wood density, microfibril angle (MFA), and modulus of elasticity (MOE) are time-consuming and expensive, which render them unsuitable for rapidly screening a large number of trees in tree breeding programs.Aim: This study aims to evaluate the suitability of using Pilodyn penetration and acoustic velocity (nondestructive evaluation) to assess wood density, MFA, and MOE for Norway spruce.Methods: Pilodyn penetration and Hitman acoustic velocity, as well as wood density, MFA, and MOE using benchmark SilviScan were measured on 5618 standing trees of 524 open-pollinated families in two 21-year-old Norway spruce (Picea abies) progeny trials in southern Sweden.Results: Strong genetic correlations were observed between Pilodyn measurement and wood density (rg = −0.96), and between acoustic velocity and MFA (rg = −0.94). Combination of Pilodyn penetration and Hitman acoustic velocity measurements (Formula presented.) obtained from standing trees showed a genetic correlation with benchmark MOE of 0.99. This combined MOE(Formula presented.) had higher selection efficiency for benchmark MOE (92 %) compared to 58–60 % using acoustic velocity alone and 78 % using Pilodyn penetration alone.Conclusion: Combination of Pilodyn penetration with Hitman acoustic velocity provided very high selection efficiency for the three most important quality traits for wood mechanical properties in Norway spruce.
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| 9. |
- Chen, Zhi-Qiang, et al.
(author)
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Genetic analysis of fiber dimensions and their correlation with stem diameter and solid-wood properties in Norway spruce
- 2016
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In: Tree Genetics & Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 12:6
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Journal article (peer-reviewed)abstract
- Adverse genetic correlations between growth traits and solid-wood, as well as fiber traits are a concern in conifer breeding programs. To evaluate the impact of selection for growth and solid-wood properties on fiber dimensions, we investigated the inheritance and efficiency of early selection for different wood-fiber traits and their correlations with stem diameter, wood density, modulus of elasticity (MOE), and microfibril angle (MFA) in Norway spruce (Picea abies L). The study was based on two large open-pollinated progeny trials established in southern Sweden in 1990 with material from 524 families comprising 5618 trees. Two increment cores were sampled from each tree. Radial variations from pith to bark were determined for rings 3–15 with SilviScan for fiber widths in the radial (RFW) and tangential (TFW) direction, fiber wall thickness (FWT), and fiber coarseness (FC). Fiber length (FL) was determined for rings 8–11. Heritabilities based on rings 8–11 using joint-site data were moderate to high (0.24–0.51) for all fiber-dimension traits. Heritabilities based on stem cross-sectional averages varied from 0.34 to 0.48 and reached a plateau at rings 6–9. The “age-age†genetic correlations for RFW, TFW, FWT, and FC cross-sectional averages at a particular age with cross-sectional averages at ring 15 reached 0.9 at rings 4–7. Our results indicated a moderate to high positive genetic correlation for density and MOE with FC and FWT, moderate and negative with RFW, and low with TFW and FL. Comparison of several selection scenarios indicated that the highest profitability is reached when diameter and MOE are considered jointly, in which case, the effect on any fiber dimension is negligible. Early selection was highly efficient from ring 5 for RFW and from rings 8–10 for TFW, FWT, and FC.
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