Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2024
Abstract
Genetic variation and performance of up to 40-year-old Norway spruce (Picea abies (L.) Karst.) families from half-diallel crosses made in natural populations where studied, and the results were compared with results from nursery test of seedlings (1-2 years from seed) and short-term farm-field tests at 6-10 years from seed. The diallel analyses revealed significant levels of additive genetic variance for growth and phenology traits. The non-additive genetic variance was generally small to moderate. Strong genetic correlations for growth performance were found between the short-term and long-term trials but not between the nursery and long-term trials. Similarly, genetic correlations for phenology traits were strong between short-term trials and long-term trials, whereas the nursery tests generally did not predict phenology at older age well. The findings indicate that early selection for growth and adaptive traits based on short-term trials is effective for improvement of long-term performance in field if the test site is not outside the normal range of deployment of the reproductive material.
Abstract
Female flowering and cone production took place in three Norway spruce progeny tests at ages 17 and 20 years, each planted with full-sib families from a half diallel. The number of cones on individual trees were scored in five classes. More than 50 % of the trees produced cones, and a considerable variation was found among families for the ability to produce cones (precocity) and for the number of clones scored in classes (fruitfulness). Both traits were strongly related to tree heights and diameters at the individual and at the family level. In general, tall trees produced the highest number of cones. However, some families produced many cones even if their average heights were low. In two of the half diallels, estimates of GCA variance components for the number of cones produced had twice the value of the SCA component, indicating additive genetic inheritance of cone production. Heritability estimates of cone scores were 0.10, 0.17 and 0.23, and the genetic correlations between cone production and tree heights were 0.40, 0.50 and 0.35 in the three half-diallels, respectively.
Abstract
Scots pine (Pinus sylvestris L.) is a commercially important forest tree species in many Eurasian countries. Its wood has been commonly utilized for production of construction timber. In Sweden, a breeding program was launched in 1950s to improve Scots pine trees to better suit industrial requirements. The emphasis was mainly put on improving stem volume, vitality, stem straightness and branching characteristics whilst wood quality was neglected. However, since some of the important wood quality traits are negatively correlated with the prioritized volume production, the continuation of such an approach could in a long run lead to irreversible deterioration of wood quality. In our study, we focused on wood quality traits that are relevant for construction timber – wood density, stiffness, strength, grain angle and sawn-board shape stability (crook, bow and twist). We linked wood quality traits nondestructively assessed on standing trees with those measured on sawn boards. We estimated narrow-sense heritabilities, genetic correlations and correlated responses to selection with the aim of identifying reliable techniques for wood quality assessment on standing trees and proposing suitable strategies for incorporating wood quality traits into the breeding program. We have concluded that standing-tree drilling resistance, acoustic velocity and grain angle are good predictors of wood density, wood stiffness & strength, and sawn-board twisting, respectively. Taking into account the long-term development on wood market, we are proposing an inclusion of wood density in the breeding program, in the way that it will be retained at the current levels rather than increased, which would also positively affect wood stiffness and strength. Furthermore, we are suggesting to consider grain angle as a breeding trait although more research is needed to unravel its underlying biological mechanism.
Abstract
Forest tree seed orchards are artificial populations of genetically superior individuals that play a crucial role in the production of high-quality seeds for reforestation and afforestation programs worldwide. In the pre-genetic-marker era, seed orchards were assumed to act as closed, panmictic populations with equal reproductive success among parents and with no gene flow from external pollen sources. Meeting these assumptions would ensure that the genetic gain attained by breeding would be efficiently transmitted to the next generation, i.e., into seed orchard crops. Many studies published to date have shown that parental reproductive success may be highly variable and that gene flow from undesired pollen sources, a.k.a. pollen contamination, can be substantial. Since the realized genetic gain can be considerably reduced, it is important to monitor mating patterns in seed orchards and thereby control the genetic quality (gain and diversity) of their crops. With the development of genetic markers, the theoretical assumptions as well as the efficiency of measures proposed to enhance desired crosses and reduce pollen contamination in seed orchards could be verified. First attempts to unravel mating patterns and quantify pollen contamination in seed orchards date back to the late 1970s when allozyme markers were introduced. Allozymes remained in use for over two decades, but due to their low resolution, they were gradually replaced with much more powerful microsatellites (SSRs), which, along with the rapid evolution of various statistical approaches, were capable of providing a much more detailed picture of seed orchards’ mating dynamics through pedigree reconstruction. Recently, SNP arrays that have been (and are being) developed for a number of commercially important forest tree species make it possible to affordably and rapidly screen seed orchard seed lots and evaluate the orchards’ genetic efficiency.
Authors
Mika Helene Kirkhus Håvard Kauserud Vigdis Vandvik Ella Thoen Ane Vollsnes Aud Helen Halbritter RechsteinerAbstract
The boreal, alpine, and arctic heaths and forests are dominated by dwarf-shrubs along with their symbionts, ericoid mycorrhizal fungi. Dwarf-shrubs are sensitive to climate change and are already affected in large-scale diebacks. It remains to explore how their mycorrhizal symbionts mitigate damages, since little is known about these plant-fungal interactions. Ericoid mycorrhizal fungi are known to aid the host plant with nutrient uptake, but little research exists on their dealings with drought, suggesting a major knowledge gap. A better overview of belowground ericoid fungi at different drought levels might help predict future climate-change induced damage. In our study we aim to find out if and how drought affects ericoid mycorrhizal fungal communities, and pinpoint key species related to drought mitigation.
Authors
Mika Helene Kirkhus Håvard Kauserud Vigdis Vandvik Ella Thoen Ane Vollsnes Aud Helen Halbritter RechsteinerAbstract
The boreal, alpine, and arctic heaths and forests are dominated by dwarf-shrubs along with their symbionts, ericoid mycorrhizal fungi. Dwarf-shrubs are sensitive to climate change and are already affected in large-scale diebacks. It remains to explore how their mycorrhizal symbionts mitigate damages, since little is known about these plant-fungal interactions. Ericoid mycorrhizal fungi are known to aid the host plant with nutrient uptake, but little research exists on their dealings with drought, suggesting a major knowledge gap. A better overview of belowground ericoid fungi at different drought levels might help predict future climate-change induced damage. In our study we aim to find out if and how drought affects ericoid mycorrhizal fungal communities, and pinpoint key species related to drought mitigation.
Authors
Anders Ræbild Kesara Anamthawat-Jónsson Ulrika Egertsdotter Juha Immanen Anna Monrad Jensen Athina Koutouleas Helle Jakobe Martens Kaisa Nieminen Jill Katharina Olofsson Anna-Catharina Röper Jarkko Salojärvi Martina Strömvik Mohammad Vatanparast Adam Vivian-SmithAbstract
Polyploidy, or genome doubling, has occurred repeatedly through plant evolution. While polyploid plants are used extensively in agriculture and horticulture, they have so far found limited use in forestry. Here we review the potentials of polyploid trees under climate change, and investigate if there is support for increased use. We find that polyploid trees like other plants have consistent increases in cell sizes compared to diploids, and that leaf-area based rates of photosynthesis tend to increase with increasing levels of ploidy. While no particular trend could be discerned in terms of biomass between trees of different ploidy levels, physiology is affected by polyploidization and several studies point towards a high potential for polyploid trees to adapt to drought stress. The ploidy level of most tree species is unknown, and analysis of geographical patterns in frequencies of polyploid trees are inconclusive. Artificial polyploid trees are often created by colchicine and in a few cases these have been successfully applied in forestry, but the effects of induced polyploidization in many economically important tree species remains untested. Polyploids would also be increasingly useful in tree breeding programs, to create synthetic hybrids or sterile triploids that could control unwanted spreading of germplasm in nature. In conclusion, this review suggests that polyploid trees may be superior under climate change in some cases, but that the potential of polyploids is not yet fully known and should be evaluated on a case-to-case basis for different tree species.
Authors
Tor MykingAbstract
No abstract has been registered
Authors
Aline Fugeray-Scarbel Laurent Bouffier Stéphane Lemarié Leopoldo Sánchez Ricardo Alia Chiara Biselli Joukje Buiteveld Andrea Carra Luigi Cattivelli Arnaud Dowkiw Luis Fontes Agostino Fricano Jean-Marc Gion Jacqueline Grima-Pettenati Andreas Helmersson Francisco Lario Luis Leal Sven Mutke Giuseppe Nervo Torgny Persson Laura Rosso Marinus JM Smulders Arne Steffenrem Lorenzo Vietto Matti HaapanenAbstract
Genetically improved forest reproductive materials are now widely accessible in many European countries due to decades of continuous breeding efforts. Tree breeding does not only contribute to higher-value end products but allows an increase in the rate of carbon capture and sequestration, helping to mitigate the effects of climate change. The usefulness of breeding programmes depends on (i) the relevance of the set of selected traits and their relative weights (growth, drought tolerance, phenology, etc.); (ii) the explicit management of targeted and “neutral” diversity; (iii) the genetic gain achieved; and (iv) the efficiency of transferring diversity and gain to the plantation. Several biological factors limit both operational breeding and mass reproduction. To fully realise the potential of tree breeding, the introduction of new technologies and concepts is pivotal for overcoming these constraints. We reviewed several European breeding programmes, examining their current status and factors that are likely to influence tree breeding in the coming decades. The synthesis was based on case studies developed for the European Union-funded B4EST project, which focused on eight economically important tree species with breeding histories and intensities ranging from low-input breeding (stone pine, Douglas-fir and ash) to more complex programmes (eucalyptus, maritime pine, Norway spruce, poplar, and Scots pine). Tree breeding for these species is managed in a variety of ways due to differences in species’ biology, breeding objectives, and economic value. Most programmes are managed by governmental institutes with full or partial public support because of the relatively late return on investment. Eucalyptus is the only tree species whose breeding is entirely sponsored and managed by a private company. Several new technologies have emerged for both phenotyping and genotyping. They have the potential to speed up breeding processes and make genetic evaluations more accurate, thereby reducing costs and increasing genetic gains per unit of time. In addition, genotyping has allowed the explicit control of genetic diversity in selected populations with great precision. The continuing advances in tree genomics are expected to revolutionise tree breeding by moving it towards genomic-based selection, a perspective that requires new types of skills that are not always available in the institutions hosting the programmes. We therefore recognise the importance of promoting coordination and collaboration between the many groups involved in breeding. Climate change is expected to bring in new pests and diseases and increase the frequency of extreme weather events such as late frosts and prolonged droughts. Such stresses will cause slow growth and mortality, reducing forest productivity and resilience. Most of these threats are difficult to predict, and the time-consuming nature of conventional breeding does not allow for an adequate and timely reaction. We anticipate that most breeding programmes will need to revise their selection criteria and objectives to place greater emphasis on adaptive performance, tolerance to multiple environmental stresses, stability in different environments, and conservation of genetic diversity. Testing breeding materials in a variety of environments, including potentially contrasting climates, will become increasingly important. Climate change may also force the incorporation of new genetic resources that provide new useful adaptations, which may involve the use of new, previously unexplored gene pools or hybridisation, with the enormous challenge of incorporating useful alleles without adding along an unfavourable genetic background. Decision-support tools to help landowners and foresters select the best-performing forest reproductive material in each specific environment could also help reduce the impact of climate change.
Authors
Jose Climent Ricardo Alía Katri Karkkainen Catherine Bastien Marta Benito-Garzon Laurent Bouffier Giovanbattista De Dato Sylvain Delzon Arnaud Dowkiw Margarita Elvira-Recuenco Delphine Grivet Santiago C. González-Martínez Haleh Hayatgheibi Sonja Kujala Jean-Charles Leplé Ruth C. Martín-Sanz Marina de Miguel M. Cristina Monteverdi Sven Mutke Christophe Plomion José Alberto Ramírez-Valiente Leopoldo Sanchez Aida Solé-Medina Jean-Paul Soularue Arne Steffenrem Angela Teani Johan Westin Richard Whittet Harry Wu Rafael Zas Stephen CaversAbstract
Purpose of Review In 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 Findings Trade-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. Summary Changing 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.