| 1. |
- Hayatgheibi, Haleh, et al.
(author)
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Estimation of genetic parameters, provenance performances, and genotype by environment interactions for growth and stiffness in lodgepole pine (Pinus contorta)
- 2019
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In: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 34, s. 1-11
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Journal article (peer-reviewed)abstract
- Genetic parameters, performance of provenances, and genotype by environment interaction (GxE) for diameter at breast height (DBH), survival, and modulus of elasticity of time-of-flight (MOEtof) (an indirect measure of stiffness), were investigated in six lodgepole pine progeny trials, aged 33-36 years, within three breeding zones in northern Sweden. Provenances of Yukon origin had the highest growth but lowest stiffness at higher latitude, while those of British Columbia (BC) origin grew faster at lower latitudes and had highest stiffness within zone 5.Combined-site heritability estimates ranged from 0.09 to 0.19 for DBH, from 0.19 to 0.27 for MOEtof, and from 0.13 to 0.26 for survival. Type-B genetic correlations () were generally high for all studied traits, except for DBH and survival in zone 4 (=0.74 and 0.40, respectively) and for MOEtof in zone 2 (=0.46). On the basis of the results obtained in this study, GxE for stiffness in northern Sweden and unfavourable growth-stiffness genetic correlation should be considered in selective breeding programmes of lodgepole pine. To achieve the highest stiffness for lodgepole pine, provenances of Yukon origin should be planted at lower latitudes and those of BC origin should be planted at lower elevations within the tested breeding zones.
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| 2. |
- Hayatgheibi, Haleh, et al.
(author)
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Genetic analysis of fiber-dimension traits and combined selection for simultaneous improvement of growth and stiffness in lodgepole pine (Pinus contorta)
- 2019
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In: Canadian Journal of Forest Research. - : Canadian Science Publishing. - 0045-5067 .- 1208-6037. ; 49, s. 500-509
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Journal article (peer-reviewed)abstract
- Quantitative genetic variation of fiber-dimension traits and their relationship with diameter at breast height (DBH) and solid-wood traits (i.e., density and modulus of elasticity (MOE)) was investigated in lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.). A total of 823 increment cores were sampled from 207 half-sib families at two independent progeny trials, aged 34-35 years, located in northern Sweden. High-resolution pith-to-bark profiles were obtained for radial fiber width (RFW), tangential fiber width (TFW), fiber wall thickness (FWT), and fiber coarseness (FC) using SilviScan. Heritabilities ranged from 0.29 to 0.74, and inheritance increased with cambial maturity. Estimated age-age genetic correlations indicate that early selection between ages 5 and 8 years is highly efficient. Our results indicate that selection for a 1% increase in DBH or MOE incurs a negligible effect on fiber-dimension traits and maximum genetic gains are reached when DBH and MOE are considered jointly. Moreover, simultaneous improvement of growth and stiffness is achievable when a selection index with 7 to 10 economical weights for MOE relative to 1 for DBH is incorporated. However, the unfavorable relationship between solid-wood traits and pulp and paper related traits suggests that breeding strategies must be implemented to improve wood quality of lodgepole pine for multiple uses.
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| 3. |
- Hayatgheibi, Haleh, et al.
(author)
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Genetic analysis of lodgepole pine (Pinus contorta) solid-wood quality traits
- 2017
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In: Canadian Journal of Forest Research. - : Canadian Science Publishing. - 0045-5067 .- 1208-6037. ; 47, s. 1303-1313
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Journal article (other academic/artistic)abstract
- Potential improvement of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) solid-wood properties was examined by estimating age trends of inheritance, age-age genetic correlations, and the efficiency of early selection using 823 increment cores sampled from 207 half-sib families at two independent progeny trials, aged 34-35 years, located in northern Sweden. High-resolution radial variation of annual ring width, wood density, microfibril angle (MFA), and modulus of elasticity (clearwood stiffness; MOES) was measured using SilviScan. The dynamic stiffness (MOEtof) of standing trees was also obtained using Hitman ST300. Heritabilities ranged from 0.10 to 0.64 for growth and earlywood, transition-wood, and latewood proportions, from 0.29 to 0.77 for density traits, and from 0.13 to 0.33 for MFA and stiffness traits. Genetic correlations between early age and the reference age (26 years) suggested that early selection is efficient at age 4 years for MFA and between ages 5 to 8 years for density and MOES. Unfavorable diameter-stiffness genetic correlations and correlated responses indicate that breeding for a 1% increase in diameter would confer 5.5% and 2.3% decreases in lodgepole pine MOES and MOEtof, respectively. Index selection with appropriate economical weights for growth and wood stiffness is highly recommended for selective breeding.
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| 4. |
- Hayatgheibi, Haleh, et al.
(author)
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Genetic control of transition from juvenile to mature wood with respect to microfibril angle in Norway spruce (Picea abies) and lodgepole pine (Pinus contorta)
- 2018
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In: Canadian Journal of Forest Research. - : Canadian Science Publishing. - 0045-5067 .- 1208-6037. ; 48:11, s. 1358-1365
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Journal article (peer-reviewed)abstract
- Genetic control of microfibril angle (MFA) transition from juvenile wood to mature wood was evaluated in Norway spruce (Picea abies (L.) Karst) and lodgepole pine (Pinus contorta Douglas ex Loudon). Increment cores were collected at breast height (1.3 m) from 5664 trees in two 21-year-old Norway spruce progeny trials in southern Sweden and from 823 trees in two lodgepole pine progeny trials, aged 34–35 years, in northern Sweden. Radial variations in MFA from pith to bark were measured for each core using SilviScan. To estimate MFA transition from juvenile wood to mature wood, a threshold level of MFA 20° was considered, and six different regression functions were fitted to the MFA profile of each tree after exclusion of outliers, following three steps. The narrow-sense heritability estimates (h2) obtained for MFA transition were highest based on the slope function, ranging from 0.21 to 0.23 for Norway spruce and from 0.34 to 0.53 for lodgepole pine, while h2 were mostly non-significant based on the logistic function, under all exclusion methods. Results of this study indicate that it is possible to select for an earlier MFA transition from juvenile wood to mature wood in Norway spruce and lodgepole pine selective breeding programs, as the genetic gains (∆G) obtained in direct selection of this trait were very high in both species.
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| 5. |
- Hayatgheibi, Haleh, et al.
(author)
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Implications of accounting for marker-based population structure in the quantitative genetic evaluation of genetic parameters related to growth and wood properties in Norway spruce
- 2024
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In: BMC Genomic Data. - : BioMed Central Ltd. - 2730-6844. ; 25:1
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Journal article (peer-reviewed)abstract
- Background: Forest geneticists typically use provenances to account for population differences in their improvement schemes; however, the historical records of the imported materials might not be very precise or well-aligned with the genetic clusters derived from advanced molecular techniques. The main objective of this study was to assess the impact of marker-based population structure on genetic parameter estimates related to growth and wood properties and their trade-offs in Norway spruce, by either incorporating it as a fixed effect (model-A) or excluding it entirely from the analysis (model-B). Results: Our results indicate that models incorporating population structure significantly reduce estimates of additive genetic variance, resulting in substantial reduction of narrow-sense heritability. However, these models considerably improve prediction accuracies. This was particularly significant for growth and solid-wood properties, which showed to have the highest population genetic differentiation (QST) among the studied traits. Additionally, although the pattern of correlations remained similar across the models, their magnitude was slightly lower for models that included population structure as a fixed effect. This suggests that selection, consistently performed within populations, might be less affected by unfavourable genetic correlations compared to mass selection conducted without pedigree restrictions. Conclusion: We conclude that the results of models properly accounting for population structure are more accurate and less biased compared to those neglecting this effect. This might have practical implications for breeders and forest managers where, decisions based on imprecise selections can pose a high risk to economic efficiency.
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| 6. |
- Hayatgheibi, Haleh
(author)
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Quantitative genetics of lodgepole pine (Pinus contorta) wood quality traits in Sweden
- 2018
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Doctoral thesis (other academic/artistic)abstract
- Stem bending, breakage, and general instability of lodgepole pine has been a major problem in northern Sweden due to low stem stiffness. The overall aim of this thesis was to evaluate the potential incorporation of wood quality traits into lodgepole pine advanced breeding programs. To achieve this, 823 increment cores were sampled from 207 half-sib families at two progeny trials of lodgepole pine and genetic variations in wood density, microfibril angle (MFA), modulus of elasticity (clearwood stiffness; MOEs), radial fibre width (RFW), tangential fibre width (TFW), fibre wall thickness (FWT), and fibre coarseness (FC) were characterised. To quantify genotype by environment interactions (G × E) for growth and stiffness and to evaluate performance of provenances, diameter at breast height (DBH) and dynamic stiffness of standing trees (MOEtof) were studied, using six 33-36 year-old lodgepole progeny trials within three different breeding zones in northern Sweden. To evaluate genetic gains in selection for an early MFA transition from juvenile to mature wood, six different regression functions were fitted to the MFA profile of each tree to delineate the age variation in MFA transition. Narrow-sense heritability estimates (ℎ2) ranged from 0.10 to 0.32 for DBH and from 0.18 to 0.76 for wood quality traits. Unfavourable genetic correlations between growth and stiffness were observed, implying that selection for a 1% increase in DBH alone, would confer 5.5% and 2.3% decreases in lodgepole pine MOEs and MOEtof, respectively. Results of the studies in this thesis indicate that simultaneous improvement of DBH and stiffness is achievable when an optimal selection index combining both traits is implemented. Additionally, it is possible to select for an earlier MFA transition from juvenile to mature wood, and thus, decreasing the proportion of the log containing juvenile wood in lodgepole pine selective breeding programs. Finally, G × E was only significant for stiffness within the northern most breeding zone. To achieve the highest stiffness for lodgepole pine, provenances of Yukon origin should be planted at lower latitudes and those of British Columbia (BC) origin should be planted at lower elevations within the tested breeding zones.
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| 7. |
- Hayatgheibi, Haleh, et al.
(author)
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The Impact of Drought Stress on the Height Growth of Young Norway Spruce Full-Sib and Half-Sib Clonal Trials in Sweden and Finland
- 2021
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In: Forests. - : MDPI AG. - 1999-4907. ; 12
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Journal article (peer-reviewed)abstract
- The summer drought of 2018 was one of the most climatically severe events in Europe that led to record-breaking temperatures and wildfires in many parts of Europe. The main objective of this study was to assess the impact of the 2018 drought on the phenotypic and genetic response of Norway spruce height growth using the Standardized Precipitation-Evapotranspiration Index (SPEI). To achieve this, the total cumulative height growth of about 6000 clones from 2016 to 2019 in four full-sib trials in Sweden, aged 6-7 years, and from 2017 to 2019 in two half-sib trials in Finland, aged 8-9 years, were measured. The results indicate that the 2018 drought caused reductions in the increment of trees. Although heritability estimates were similar to other reports for Norway spruce, the additive genetic variance was highly inflated in one of the visibly drought-damaged trials in Southern Sweden. Similarly, the genotype by environment (G x E) interaction was highly significant in the drought-damaged Southern Swedish trials. Both additive genetic and phenotypic correlations obtained between height increments in 2019 and final heights were the weakest in all studied trials, implying that the drought legacies might have influenced the recovery of trees in 2019. We may conclude that the severe drought can be an underlying factor for a strong G x E interaction and changes in the ranking of genotypes. Therefore, a selection of drought-resistant genotypes with a good growth capacity tested in variables sites should be considered as an important criterion for future breeding of Norway spruce.
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| 8. |
- Hayatgheibi, Haleh, et al.
(author)
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Trade-offs and Trait Integration in Tree Phenotypes: Consequences for the Sustainable Use of Genetic Resources
- 2024
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In: Current Forestry Reports. - 2198-6436. ; 10, s. 196–222-
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Research review (peer-reviewed)abstract
- Purpose of ReviewIn this review, we synthesise current knowledge on trade-offs among traits in key fitness dimensions and identify major research gaps with the intention of laying the groundwork for a rapid advance in tree breeding for multiple objectives as a key contribution to the sustainability of planted forests in the future.Recent FindingsTrade-offs among growth, reproduction, defence, stress tolerance and product quality predicted theoretically have been reported experimentally in many breeding programmes. Among these trade-offs, the genetic linkage between resistance against biotic threats and growth (or other relevant traits) is particularly critical for the current and future management of forest genetic resources. Maintaining tree growth and wood quality in the novel environments of the future requires the assessment of genetic correlations of target traits with phenology, closely linked to survival to temperature extremes. Improving our current knowledge on the genetic trade-offs of drought tolerance as a breeding objective in forest trees obligates a more precise definition of both the specific traits and the experimental conditions. Published evidence suggests that common target traits in breeding programmes may trade-off with reproductive success and fire-adaptation, and the simultaneous improvement of growth and wood quality traits still remains as a constraint in traditional tree breeding.SummaryChanging environments combined with pests and diseases are challenging plantation forestry worldwide, which implies an urgent need to develop new improvement strategies to build the resilience of forestry for our future environments. It is essential to have a better understanding of how traits interact, especially those important for production, climate and biotic threat resilience, but much of the information is still missing. Since many key trade-offs are affected by the environment, we need new studies under novel environments to forecast levels of multi-trait integration in breeding populations.
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