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| 2. |
- Berlin Kolm, Sofia, et al.
(författare)
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QTL mapping of biomass and nitrogen economy traits in willows (Salix spp.) grown under contrasting water and nutrient conditions
- 2014
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Ingår i: Molecular Breeding. - : Springer Science and Business Media LLC. - 1380-3743 .- 1572-9788. ; 34, s. 1987-2003
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Tidskriftsartikel (refereegranskat)abstract
- In order to efficiently grow Salix for biomass production in warmer climates, varieties with a desirable response to drought and nutrient-limiting conditions are needed. The main objective of this study was to investigate the genetic background of biomass production and nitrogen (N) economy in contrasting conditions of water and nutrient availability and to identify candidate genes with a putative function in the expression of the different traits. Quantitative trait loci (QTLs) analysis was conducted using data from 198 individuals of a back-cross population between S. viminalis and S. schwerinii grown in a greenhouse under three combinations of N and water supply. In total, 60 QTLs were identified for biomass and N economy traits in the different treatments. Most of the QTLs mapped to linkage groups II, III, VI, X, XIII and B. At linkage groups III, VI and X, QTLs for both N economy and biomass traits co-located. The phenotypic variation explained by each QTL varied from 7.7 to 41.9 % of the total variance. QTLs for N economy traits explained most of the variation. Gene ontology (GO) analyses, performed on QTL intervals for each trait and projected to the Populus trichocarpa genome, revealed that genomic intervals connected to 19 traits were enriched for at least one GO term. Candidate genes were selected among genes linked to the enriched GO terms. These results represent a first necessary step for additional mapping and functional studies and encourage the development of marker-assisted breeding of Salix varieties adapted to drier climates.
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| 3. |
- Bonosi, Lorenzo, et al.
(författare)
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Growth responses of 15 Salix genotypes to temporary water stress are different from the responses to permanent water shortage
- 2010
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Ingår i: Trees - Structure and Function. - : Springer Science and Business Media LLC. - 0931-1890 .- 1432-2285. ; 24, s. 843-854
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Tidskriftsartikel (refereegranskat)abstract
- Hybrids of willow (Salix spp.) are today grown as biomass crops for energy in several cool-temperate regions including Sweden. These trees have great growth potential also under warmer climates, but may suffer from drought and heat. Research on tree growth under drought has often focused on the responses to permanent water stress. Less attention has been paid to the effects of temporary water stress on tree growth, although periods of strong water shortage are recurrent in many regions of the world. We performed a greenhouse experiment to assess the impact of five treatments including permanent (PWS; 30 days of water shortage) and temporary (TWS; 4-12 days of water shortage followed by normal watering) water stress on growth and leaf traits of 15 Salix genotypes. Plant biomass and height increment decreased across treatments in the order control (well-watered) > TWS > PWS, but there was also a significant genotype x treatment interaction. The pattern in growth traits was not directly reflected by the leaf traits, for which there was no significant genotype x treatment interaction (except for leaf angle). The significant genotype x treatment interactions for growth traits indicate a potential for breeding. Permanent water shortage does not necessarily represent an appropriate environment for the selection of genotypes for environments characterised by temporary water stress.
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| 6. |
- Ghelardini, Luisa, et al.
(författare)
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Quantitative Trait Loci analysis of traits related to biomass production in willow (Salix spp.)
- 2010
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Konferensbidrag (refereegranskat)abstract
- Willow trees (Salix spp.) have received increasing attention during the last decades for the purpose of bio-energy production in Europe. Willows are especially suitable for biomass production by short rotation cultivation because of their fast growth and high capacity to resprout after coppicing. However, achieving high biomass yields with relatively low inputs of energy requires development of high-yielding cultivars both suitable for plantation in different environments and efficient in the use of available resources. Selection and breeding of biomass willows would largely benefit from the use of easily detectable genetic markers linked to genes underlying economically important traits. In this study we present the results of quantitative trait loci (QTLs) analysis performed on several traits that are important determinants of biomass production and promising targets for the breeding of biomass willows. We mapped QTLs for growth, resource-economy-related traits such as biomass allocation, water use efficiency, leaf area efficiency, leaf nitrogen content and leaf nitrogen efficiency, and phenology traits such as timing of bud burst, growth cessation, and leaf senescence, in an experimental cross of Salix viminalis L. and Salix schwerinii E. Wolf . In the QTL analysis we used a dense genetic linkage map that we have constructed for the same population. The map was built using SNP markers located within genes evenly distributed throughout the Populus trichocarpa genome and it is thus aligned to the poplar physical map. We found high degree of synteny and gene order conservation between the genomes of willow and poplar. The use of the map aligned to the poplar genome allowed us to search for annotated genes the regions of the poplar genome corresponding to the QTLs found in Salix and to identify candidate genes putatively involved in the control of these traits
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| 7. |
- Weih, Martin, et al.
(författare)
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Assessment of Genotype Ranking in Long-term Biomass Production of Salix Based on Juvenile Plant Traits: Breeding Implications
- 2009
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Ingår i: BioEnergy Research. - : Springer Science and Business Media LLC. - 1939-1234 .- 1939-1242. ; 2, s. 29-36
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Tidskriftsartikel (refereegranskat)abstract
- Willow (Salix spp.) is among the most promising energy crops to be grown on agricultural land and breeding research to increase biomass yield of this perennial crop is performed in Europe and North America. Biomass willows are grown in short rotation and harvests are performed every 3 to 5 years (i. e., at 3- to 5-year cutting cycles) for a period of up to 25 years. However, breeding programs to improve long-term biomass yield are often relying on the results of short-term screening studies performed on juvenile plants. A pre-requisite for successful breeding of perennial energy crops is thus the identification of relevant juvenile plant traits indicative of long-term plant performance under field conditions. In this study a number of juvenile plant traits, measured at various Salix genotypes grown in a short-term experiment were evaluated in terms of their capacity to predict the long-term performance in biomass production after the first and second cutting cycle. The objective was to develop a simple model linking juvenile plant traits such as shoot biomass, total leaf area and leaf nitrogen (N) concentration to the long-term biomass productivity of field-grown plants. A two-component regression model combining juvenile shoot biomass and leaf N concentration provided the highest prediction accuracy (coefficients of determination around 0.8). The model based on two easy-to-measure juvenile plant traits clearly has implications for willow breeding programs. The implications for breeding are discussed in the light of the possibilities and limitations associated with the chosen approach.
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| 8. |
- Weih, Martin, et al.
(författare)
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Optimizing nitrogen economy under drought: increased leaf nitrogen is an acclimation to water stress in willow (Salix spp.)
- 2011
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Ingår i: Annals of Botany. - : Oxford University Press (OUP). - 0305-7364 .- 1095-8290. ; 108, s. 1347-1353
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Tidskriftsartikel (refereegranskat)abstract
- Conclusions It is concluded that N-uptake efficiency and leaf N efficiency are important traits to improve growth under drought. Increased leaf N content (area basis) is an acclimation to optimize N economy under drought. The leaf N content is an interesting trait for breeding of willow bioenergy crops in a climate change future. In contrast, leaf biomass allocation is a less interesting breeding target to improve yield under drought.
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