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.
2007
Authors
Odd Arne Rognli Trygve Aamlid Lars T. Havstad Birte BoeltAbstract
The potential tradeoffs between vegetative and reproductive growth is a constant challenge for the forage plant breeders. Breeding for seed production has inevitably played a secondary role compared to improvements of the vegetative production. In this paper the current status regarding genetic variation, genotype x environment interactions, heritability estimates and mapping of quantitative trait loci (QTL) for seed yield and seed yield components in grasses and legumes are reviewed, with special focus on important forage grasses. Investigations of seed yield components have shown that components contributing to an increased utilization of the reproductive potential, like seed set and seed retention, seems efficient in increasing seed yield without adverse effects on the vegetative production. The generation of transgenic plants (GMO) have been reported for many forage species, and genetic engineering will increasingly be used to manipulate traits like nutritive value, resistance to fungal and viral diseases, and the reproductive system like male and female sterility and apomixis. Turf and forage grasses, and forage legumes are outcrossing species with prolific pollen production and pollination facilitated by wind or insects. They are potentially some of the most problematic crops when it comes to gene flow by pollen especially during the generations of seed multiplication. GM plants with engineered reproductive systems will pose new challenges for the seed producers. Co-existence of GM grasses and legumes with conventional and organic seed production will be very difficult to establish, and commercialization of GM cultivars will therefore certainly require gene containment technologies that prevent or reduce transgene escape. Mapping of QTLs, identification of markers and candidate genes associated with seed yield components, and the utilization of comparative genomics with cereal species have revealed several key components which may facilitate development of markers for marker-assisted breeding for the improvement of seed yield.
Abstract
High mortality among chicks, due to fragmentation and changes in habitat caused by commercial forestry, is considered one of the main reasons for the general decline in capercaillie Tetrao urogallus in boreal forests. Using GPS satellite telemetry, we studied the movement patterns of young capercaillie broods: 1) to test if this new technology could be applied to gain more detailed insight into behaviour and habitat selection at a small spatial scale, and if so, 2) to compare the broods' relative use of planted and older, naturally regenerated forests. Hens of four broods with chicks 2-7 days old were captured and fitted with 90-g backpacks containing GPS units and VHF transmitters. The GPS units were programmed to record positions every 15 minutes, the shortest interval possible. With a storage capacity of 450 positions, movements could be monitored for ca 4.5 days. In our study area (Varaldskogen) with moderate topography, the GPS technology performed quite well. A total of 1,277 positions were obtained (84% of potential maximum), of which 77% were within 20 in of the true position of the brood. The movement patterns of the four broods were quite similar, with a mean speed of 83.2 m +/- 9.9 (SE) per hour during the 4.5-day tracking period. Broods moved almost continuously during the 24-hour cycle, presumably foraging, although their speed was slower at night. The two oldest broods whose initial age was seven days moved faster than the two younger broods whose initial age was two and three days, respectively. Strong autocorrelation among successive positions made us examine habitat selection using a binominal choice method for each brood separately. When broods were inside old 'natural' forest, they remained there instead of moving into plantations. When inside plantations, they did not discriminate between remaining there and moving into nearby old forest, but they tended to move faster in plantations than in old forest. Clearly, the new, cost-effective GPS telemetry offers new and better opportunities for studying small-scale brood movement. Very frequent and accurate positions can be obtained without either disturbing the birds or leaving scent marks that may attract predators.
Authors
Lone Ross Gobakken Kolbjørn Mohn JenssenAbstract
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Authors
Rosario Mosello Nicholas Clarke John Derome Kirsti Derome Anna Kowalska Aldo Marchetto Pia Sorsa Gabriele A. Tartari Erwin Ulrich Nils KönigAbstract
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Authors
Jørn Kristian LilengAbstract
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Abstract
The root-rot causing fungus Heterobasidion annosum senso lato is the most devastating pathogen of conifers in Europe. This pathogen enter Norway spruce trees trough the roots and colonizes the tree from within, growing as a saprophyte when established within the dead heartwood and acting as a necrotroph when in contact with living host tissue. Twenty percent of the trees in Norwegian spruce stands tend to be infected and this pathogen that can colonize ten meters up inside the tree trunk, decaying the silvicultural most valuable part of the tree. Despite this high incidence of damage the tree has efficient defences against this pathogen and the attack is eventually fought off if present in the bark or living wood. The tree also has a defense against this internal attack (by Heterobasidion established in the heartwood expanding and invading outward toward the living sapwood) by forming a reaction zone; in this case the host defense is directed inwardly by the still living sapwood toward the central colonized wood. We have in the last years studied the host responses to infection in Norway spruce clones at the transcriptional level and found that the speed of recognition and that spatial defense signalling appears to be the hallmarks of trees with high degree of resistance. We strive to study both partners in this pathosystem from a molecular perspective, and are now focusing on the pathogen and what fungal gene-products are being expressed during the colonization of the heartwood compared to those expressed close to the active host defense (reaction zone) using suppressive subtractive hybridization (SSH) followed by Real-Time RT PCR analysis. In addition the colonization profiles were followed on extracted gDNA using quantitative Real-Time PCR.
Authors
Carl Gunnar FossdalAbstract
Our goal is to study what gene products (mRNA and proteins) are important for trees in order to fend off pathogens. We are interested in the genetic basis of resistance focusing on the molecular basis of both the local and systemic defence responses of trees. So far we have focused on the host defense against necrotrophic fungi and studied the expression and role of defensins, peroxidases, chitinases, CHS, PAL, CAD and a number of other host gene products. Earlier work using clonal trials (in both Sweden and Norway) indicate that there is a genetic basis for resistance to the root-rot causing fungus Heterobasidion annosum s.l.. We have studied the timing and spatial signaling of the defense response in mature Norway spruce trees as well as seedlings and found that the molecular responses differ. Our studies suggest that the time from wounding and infection to induction of defense-related expression is shorter in resistant spruce clones indicating a more efficient host defense response than in susceptible trees.
Authors
Nicolette Fouche Jolanda Roux Halvor Solheim Ronald N. Heath Gilbert Kamgan Nkuekam P. Chimwamurumbe K.G. Pegg Michael J. WingfieldAbstract
No abstract has been registered