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
Authors
Carl Gunnar Fossdal Paal Krokene Jorunn Elisabeth Olsen George Richard Strimbeck Marcos Viejo Igor A. Yakovlev Melissa MagerøyAbstract
Gymnosperms are long-lived, cone-bearing seed plants that include some of the most ancient extant plant species. These relict land plants have evolved to survive in habitats marked by chronic or episodic stress. Their ability to thrive in these environments is partly due to their phenotypic flexibility, and epigenetic regulation likely plays a crucial part in this plasticity. We review the current knowledge on abiotic and biotic stress memory in gymnosperms and the possible epigenetic mechanisms underlying long-term phenotypic adaptations. We also discuss recent technological improvements and new experimental possibilities that likely will advance our understanding of epigenetic regulation in these ancient and hard-to-study plants.
Authors
Cecilie Marie Mejdell Grete H. Meisfjord Jørgensen Knut Egil BøeAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Xiao-Yan Ma Dag-Ragnar Blystad Qiao-Chun Wang Lu Tong Øyvor Stensbøl Dong Zhang Zhibo HamborgAbstract
By optimizing size of shoot tips, preculture medium and exposure duration to PVS2, we established an efficient and wide-spectrum droplet-vitrification cryopreservation for shoot tips of raspberry (Rubus idaeus L.). This protocol yielded 80–100% and 67–100% of survival and shoot regrowth levels in cryopreserved shoot tips across 23 raspberry genotypes. Genetic integrity was assessed in cryo-derived regenerants after 3 months of post-cryopreservation using inter simple sequence repeat (ISSR), single nucleotide polymorphism (SNPs), and insertions and deletions (InDels). ISSR did not detect any polymorphic bands in the cryo-derived regenerants. Although the number of SNPs and InDels decreased in the cryo-derived regenerants, variation trends were similar between the cryo-derived regenerants and the control. Plant vegetative growth and root growth were assessed in the cryo-derived plants after 9 weeks of growth in greenhouse. There were no significant differences in plant vegetative growth measured by plant height, number of fully-opened leaved, leaf area, and fresh and dry weight between the cryo-derived plants and the control, although significant differences were observed in root growth measured by root total length, root average diameter and root volume between the two types of plants. The results obtained in the present study indicate that the droplet-vitrification method has great potential for cryopreservation of raspberry germplasm.
Abstract
Successful introduction of the new cultivars requires proper pomological, phenological and as well as technological evaluation. It is particularly important at the harsh Norwegian climate conditions. Investigations were conducted with apple cultivar ‘Eden‘ / ‘Wursixo‘ (WUR 6), with the aim to establish an optimal balance between yield, fruit quality and bearing regularity. Four different crop load levels were tested in 3 consecutive years in the orchard planted 3.5 x 1 m and trained as slender spindle. Lower crop load levels guaranteed good return bloom, a very high share of fruits harvested during the first picking, and larger fruits. Increasing crop load led to less intensive return bloom, smaller fruit sizes and higher share of fruits harvested during the second picking. It was found that ‘Eden‘ is strictly alternating cultivar and precise crop load levels according to the tree age and tree vigour were defined. In order to keep ‘Eden‘ trees in regular bearing mode crop load levels should be maintained at 4.5-5 fruits cm-2 of trunk cross-sectional area (TCSA) in the 3rd and 6-7 fruits in the 4th growing season
Authors
Trygve S. Aamlid Sigridur Dalmannsdottir Marit Jørgensen Kristoffer Herland Hellton Akhil Reddy Pashapu Ievina Sturite Mallikarjuna Rao Kovi Helga Amdahl Carl Gunnar Fossdal Odd Arne RognliAbstract
Timothy ( Phleum pratense L.) is the predominant forage grass species in the northern parts of the Nordic region. Because of the long andharsh winters and a short growing season, most of it with continuous light, the need for locally adapted timothy seed has been recognizedfor more than a century. However, the seed production of timothy in these marginal environments is unpredictable with acceptable seedyield and quality on average only every third year. Thus, a multiplication scheme for the northern cultivars was established with only pre-basic seed produced in the north, and basic and certified seed produced further south to secure enough seed of good quality. In recentdecades this scheme has been more or less abandoned with continous generations produced in the south. Farmers are complaining andare questioning whether the cultivars has changed and lost winter hardiness. We studied freezing and ice-encasement tolerance of generations of the the northern timothy cultivars ‘Engmo’ (old landrace) and ‘Noreng’(synthetic) multiplied for one, two or three generations in Central, Southern and Northern Norway. The trials introduce very largedifferences in mean temperature, growing degree days and photoperiod between place of parental origin and sites of multiplication so theeffects on fitness observed could arise from both selection and and induced epigenetic changes. Large changes (loss) in freezing and ice-encasement tolerance were observed, especially at the southern location in the first generation.The cultivars behaved differently and there were significant interactions. The extreme phenotypic changes observed might be explained bygenetic selection or epigenetic memory of the environmental conditions experienced during seed production, or a combination of the two.We are currently analysing GBS data of all generations and this will be used to test whether genetic shifts has occured during themultiplication in the different environments.
Abstract
No abstract has been registered
Abstract
Floral initiation in biennial-fruiting red raspberry is controlled by the interaction of temperature and photoperiod. To determine the threshold temperatures for short day (SD) floral initiation in early- and late-flowering cultivars, we exposed plants of ‘Glen Ample’, ‘Glen Mor’ and ‘Duo’ to 12°, 16° and 20°C in a daylight phytotron under naturally decreasing autumn daylength at Ås, Norway (59°40’N). While none of the cultivars ceased growing or initiated floral primordia at 20°C, ‘Glen Ample’ and ‘Glen Mor’ initiated buds at 12° and 16°C, whereas ‘Duo’ formed flower buds at 12°C only. Surprisingly, however, all plants flowered abundantly in spring after winter chilling in the dark at −1.5 ± 0.5°C for 7 months. We discuss two possible explanations for this unusual and novel flowering response. Fractional induction is well known in raspberry, and we visualise that in SD at 20°C, the SD requirement is fulfilled, while floral induction is still blocked by inappropriate temperature. A vernalisation-like response is alternatively suggested as this can take place at near-freezing temperatures in the dark. A combination of the two mechanisms is also possible and likely. We conclude, however, that the two floral induction processes are fundamentally different and controlled by different physiological mechanisms.
Abstract
Mapping individual tree quality parameters from high-density LiDAR point clouds is an important step towards improved forest inventories. We present a novel machine learning-based workflow that uses individual tree point clouds from drone laser scanning to predict wood quality indicators in standing trees. Unlike object reconstruction methods, our approach is based on simple metrics computed on vertical slices that summarize information on point distances, angles, and geometric attributes of the space between and around the points. Our models use these slice metrics as predictors and achieve high accuracy for predicting the diameter of the largest branch per log (DLBs) and stem diameter at different heights (DS) from survey-grade drone laser scans. We show that our models are also robust and accurate when tested on suboptimal versions of the data generated by reductions in the number of points or emulations of suboptimal single-tree segmentation scenarios. Our approach provides a simple, clear, and scalable solution that can be adapted to different situations both for research and more operational mapping.
Authors
Kalkidan Mulatu Ayele Shimelis Gizachew Raji Bimrew Asmare Niklas Wickander Solomon Mwendia Peter Dörsch W. A. Worku Caroline Brophy Karl Thunes Marit JørgensenAbstract
EthiopiaGrass Fact sheet. 1 p.