| 1. |
- Araki, N.H.T., et al.
(författare)
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Phylogeography of Larix sukaczewii Dyl. and Larix sibirica L. inferred from nucleotide variation of nuclear genes
- 2008
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Ingår i: Tree Genetics & Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 4, s. 611-623
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Tidskriftsartikel (refereegranskat)abstract
- We investigated phylogeography of Larix sukaczewii and Larix sibirica using nucleotide variation at three following nuclear gene regions: 5.8 S rDNA including two internal transcribed spacers (ITS), cinnamyl alcohol dehydrogenase (CAD), and phytochrome-O (PHYO). We also included sequences of the 4-coumarate: coenzyme A ligase (4CL) gene region obtained in our recent study. CAD and PHYO showed very low nucleotide variation, but ITS and 4CL had levels of variation similar to those reported for other conifers. Pleistocene refugia have been hypothesized to exist in the Southern Urals and South Central Siberia, where four out of nine of the investigated populations occur. We found moderate to high levels of population differentiation (FST=0.115–0.531) in some pairwise comparisons suggesting limited gene flow and independent evolution of some refugial populations. In L. sukaczewii, low levels of differentiation were found among populations from areas glaciated during the Pleistocene, indicating their recent origin. Our results also suggest these populations were created by migrants from multiple, genetically distinct refugia. Furthermore, some haplotypes observed in populations from previously glaciated areas were not found in putative refugial populations, suggesting these populations might have contributed little to the extant populations created after the Last Glacial Maximum. Some authors regard L. sukaczewii and L. sibirica as a single species, while others consider them as separate species. The observed conspicuous differences in haplotype composition and distribution between L. sukaczewii and L. sibirica, together with high values of FST between populations of the two species, appear to support the latter classification.
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| 2. |
- Babst, Benjamin A, et al.
(författare)
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Local and systemic transcriptome responses to herbivory and jasmonic acid in Populus
- 2009
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Ingår i: The Genetics & Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 5:3, s. 459-474
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Tidskriftsartikel (refereegranskat)abstract
- We used DNA microarrays to examine local and systemic transcriptional responses to herbivory by gypsy moth larvae (GM) and exogenous jasmonic acid (JAtrt) in leaves of Populus nigra L. to identify candidate signaling and defense genes and also to examine primary metabolism, as might relate to tolerance of damage. GM and JAtrt altered expression of over 800 genes, most of which have putative roles in defense signaling, secondary metabolism, and primary metabolism. Additionally, numerous uncharacterized genes responded to herbivory, providing a rich resource for future studies. There was limited overlap (14%) between the responses to GM and JAtrt. GM did, however, result in strong upregulation of genes involved not only in JA biosynthesis but also abscisic acid biosynthesis and other signaling pathways. GM induced known resistance transcripts, including polyphenolic biosynthetic genes, proteinase inhibitors, and amino acid deaminases. According to GOStats pathway level analysis, GM altered primary metabolism, including aromatic amino acid biosynthesis, fatty acid β-oxidation, and carbohydrate and organic acid metabolism. These alterations may be related to increased demands for substrate for secondary metabolites or may serve a tolerance-related role. Responses were more intense locally in treated leaves than in untreated (systemic) leaves and systemic responses were mostly a subset of the genes induced locally. A stronger local response might be needed to cope with localized stresses and wound healing. Since Populus in general and this clone in particular are known for their systemic induced resistance, genes induced both locally and systemically may be the highest quality candidates for resistance.
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| 3. |
- Berlin Kolm, Sofia, et al.
(författare)
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Genetic diversity, population structure and phenotypic variation in European Salix viminalis L. (Salicaceae)
- 2014
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Ingår i: Tree Genetics & Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 10:6, s. 1595-1610
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the potential of association genetics for willow breeding, Salix viminalis germplasm was assembled from UK and Swedish collections (comprising accessions from several European countries) and new samples collected from nature. A subset of the germplasm was planted at two sites (UK and Sweden), genotyped using 38 SSR markers and assessed for phenological and biomass traits. Population structure, genetic differentiation (F-ST) and quantitative trait differentiation (Q(ST)) were investigated. The extent and patterns of trait adaptation were assessed by comparing F-ST and Q(ST) parameters. Of the 505 genotyped diploid accessions, 27 % were not unique. Genetic diversity was high: 471 alleles was amplified; the mean number of alleles per locus was 13.46, mean observed heterozygosity was 0.55 and mean expected heterozygosity was 0.62. Bayesian clustering identified four subpopulations which generally corresponded to Western Russia, Western Europe, Eastern Europe and Sweden. All pairwise F-ST values were highly significant (p<0.001) with the greatest genetic differentiation detected between the Western Russian and the Western European subpopulations (F-ST = 0.12), and the smallest between the Swedish and Eastern European populations (F-ST = 0.04). The Swedish population also had the highest number of identical accessions, supporting the view that S. viminalis was introduced into this country and has been heavily influenced by humans. Q(ST) values were high for growth cessation and leaf senescence, and to some extent stem diameter, but low for bud burst time and shoot number. Overall negative clines between longitudinal coordinates and leaf senescence, bud burst and stem diameter were also found.
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| 4. |
- Calleja-Rodriguez, Ainhoa, et al.
(författare)
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Genotype-by-environment interactions and the dynamic relationship between tree vitality and height in northern Pinus sylvestris
- 2019
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Ingår i: Tree Genetics and Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Tree health and growth rate must both be considered in Scots pine breeding for harsh areas such as northern Sweden. Univariate (UV) and multivariate (MV) multi-environment trial (MET) analyses of tree vitality (a measure of tree health) and height (a measure of growth rate) were conducted for four series of open-pollinated Scots pine progeny trials (20 trials total), to evaluate age trends, patterns, and drivers of genotype-by-environment interaction (G x E). The lowest standard errors were obtained for the MV MET analyses, indicating that MV analyses are preferable to UV analyses. By incorporating factor-analytic structures, the most complex data sets could be handled, suggesting that factor-analytic analyses are preferred for evaluation of forest progeny trials. We detected strong patterns of G x E for both tree vitality and height, and the driver of G x E was found mainly to be differences in degree day temperature sum, such that G x E was higher between trials with more contrasting temperature sums. The genetic correlations, between vitality and height within sites, were generally positive and were driven by the harshness of the trial; mild trials had lower genetic correlations than did harsh trials. The sign of the across-site genetic correlations between vitality and height changed from positive to negative in some cases, as the differences between the temperature sum of the trials increased. These findings support the hypothesis that tree height assessed in harsh environments with low survival is likely to reflect health and survival ability to a greater extent than growth capacity.
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| 5. |
- Chen, Zhiqiang, et al.
(författare)
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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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Ingår i: Tree Genetics & Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 10:5, s. 1291-1303
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Chen, Zhiqiang, et al.
(författare)
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Patterns of additive genotype-by-environment interaction in tree height of Norway spruce in southern and central Sweden
- 2017
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Ingår i: Tree Genetics and Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Genotype-by-environment (G x E) interaction for tree height measured at ages 7 to 13 was investigated in 20 large open-pollinated progeny trials for Norway spruce (Picea abies (L.) H. Karst.) in southern and central Sweden. Factor analytic method using spatially adjusted data and a reduced animal model was used to explore the pattern of G x E interaction. Extended factor analyses captured 93.0% of additive G x E interaction variances using three factors. The mean daily temperature less than 3.2 degrees C in May and June explained 27.8% G x E interaction, and it was moderately correlated with the first factor, indicating that spring or autumn frost weather condition could be a main driver for G x E interaction in Norway spruce. Cluster analysis has divided 20 trials into either 6 clusters or 3 clusters. Both sets of clusters reflected the geography of the trials (climates) and the genetic connectedness among testing series, indicating that more trials with better connectedness are required to examine whether current delineation of breeding or seed zones is optimal. Parental stability using latent regression could be used to locate best parents that have the highest breeding values and are highly stable across trials.
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| 7. |
- Chen, Zhi-Qiang, et al.
(författare)
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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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Ingår i: Tree Genetics & Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 12:6
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Tidskriftsartikel (refereegranskat)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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| 8. |
- Fady, Bruno, et al.
(författare)
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Genetics to the rescue : managing forests sustainably in a changing world
- 2020
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Ingår i: Tree Genetics & Genomes. - : SPRINGER HEIDELBERG. - 1614-2942 .- 1614-2950. ; 16:6
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Tidskriftsartikel (refereegranskat)abstract
- There is growing concern that the implementation of political agreements on climate change and biodiversity will not be enough to protect forests in the short run and up to the end of the 21st century. As mitigation efforts are lagging behind self-imposed, reasonable targets, genetic diversity will have a large and significant part to play in the process of adapting forests to climate change. Genetic diversity, the raw material of evolution, can be used for adaptation by natural selection and artificial breeding, in naturally regenerated and plantation forests alike. The 2-day scientific conference: "#rescueforests: Genetics to the rescue - Managing forests sustainably in a changing world," addressed the genetic diversity of forests. More specifically, the conference was about natural as well as assisted adaptive processes, their spatial scale, from fine grain to landscape and ecoregions, and how much of the genome it involves. It also dealt with phenotypes and how much of their variation is determined by underlying genetic diversity. And finally, and perhaps most importantly, the conference emphasized the importance of conservation and sustainable use of this genetic diversity as a nature-based solution to adapt under the fast pace of climate change. The conference demonstrated how improved knowledge on genomic diversity and evolutionary mechanisms can help to rescue forests, either naturally or by means of management.
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| 9. |
- Funda, Tomas, et al.
(författare)
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Mating dynamics of Scots pine in isolation tents
- 2016
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Ingår i: Tree Genetics & Genomes. - : Springer Berlin/Heidelberg. - 1614-2942 .- 1614-2950. ; 12:6
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Tidskriftsartikel (refereegranskat)abstract
- Seed orchards are forest tree production populations for supplying the forest industry with consistent and abundant seed crops of superior genetic quality. However, genetic quality can be severely affected by non-random mating among parents and the occurrence of background pollination. This study analyzed mating structure and background pollination in six large isolation tents established in a clonal Scots pine seed orchard in northern Sweden. The isolation tents were intended to form a physical barrier against background pollen and induce earlier flowering relative to the surrounding trees. We scored flowering phenology inside and outside the tents and tracked airborne pollen density inside and outside the seed orchard in three consecutive pollination seasons. We genotyped 5683 offspring collected from the tents and open controls using nine microsatellite loci, and assigned paternity using simple exclusion method. We found that tent trees shed pollen and exhibited maximum female receptivity approximately 1 week earlier than trees in open control. The majority of matings in tents (78.3 %) occurred at distances within two trees apart (about 5 m). Self-fertilization was relatively high (average 21.8 %) in tents without supplemental pollination (SP), but it was substantially reduced in tents with SP (average 7.7 %). Pollen contamination was low in open controls (4.8-7.1 %), and all tents remained entirely free of foreign pollen. Our study demonstrates that tent isolation is effective in blocking pollen immigration and in manipulating flowering phenology. When complimented with supplemental pollination, it could become a useful seed orchard management practice to optimize the gain and diversity of seed orchard crops.
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| 10. |
- Garcia Gil, Rosario, et al.
(författare)
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Genetic diversity and inbreeding in natural and managed populations of Scots pine
- 2015
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Ingår i: Tree Genetics and Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- We carried out a study on Scots pine (Pinus sylvestris L.) in Sweden, where our objective was to quantify the genetic diversity and inbreeding associated with two widely used managed-regeneration practices, planting with improved material from seed orchards and seed-tree regeneration, and compare these with that found in unmanaged natural forests. A total of 196 evenly spaced trees were sampled from a naturally regenerated and two managed-regeneration stands (plantation and seed-tree), in each of three different regions in Sweden (Arjeplog, Vihelmina, and Hammerdal). Population parameters were estimated for microsatellite loci from the nuclear and chloroplast genomes (5 and 11 loci, respectively) and a single mitochondrial locus (nad7). Analysis of variance (ANOVA) shows no significant effects of stand management on the level of nuclear and mitochondrial genetic diversity or inbreeding (p<0.05). Duncan post-hoc analysis suggested significantly lower values for the chloroplast number of effective alleles (N-ea_CP) and total gene diversity (H-t_CP) for natural and plantation practices, as compared with seed-tree regeneration. The ANOVA supported a rather weak effect of the management factor (M) on N-ea_CP and H-t_CP, with p values of 0.08 and 0.07, respectively. Inbreeding coefficient (F-5) indicated a deviation from random mating in all stands caused by an excess of homozygotes. All the stands are composed of a mixture of half-and full-sibs, but no pattern of spatial relatedness was detected in any of them. Our data suggest that genetic diversity is similar in both natural stands and those with managed regeneration, probably because regeneration practices did not decrease the population size to a point where random drift effects might be important. The estimates for the nuclear and mitochondrial (mt) genomes should be regarded with caution, as only five nuclear microsatellite (nSSR) loci less affected by null alleles (<25 %) were analyzed. Our investigation indicates that the reduction to five nSSR loci does not change the main finding of an absence of differences in genetic diversity among stands, except for the number of rare alleles (RA), which is lower when estimated from data for eight nSSR loci.
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