Sigridur Dalmannsdottir
Research Scientist
(+47) 465 46 249
sigridur.dalmannsdottir@nibio.no
Place
Tromsø
Visiting address
Holtvegen 66, 9016 Tromsø
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.
Authors
Akhil Reddy Pashapu Sigridur Dalmannsdottir Marit Jørgensen Marian Schubert Odd Arne Rognli Mallikarjuna Rao KoviAbstract
The sustainable production of perennial grasses in Northern Norway is at risk due to the ongoing climate change. The predicted increase in temperatures and variable weather patterns are further expected to create challenges for winter survival of timothy (Phleum pratense L.). Knowledge about the molecular mechanisms underlying freezing tolerance is crucial for developing robust cultivars. The current study is aimed at identifying genes involved in freezing stress response of timothy and studying gene expression differentiation due to field selection in contrasting environments using RNAseq. Four timothy cultivars were field tested for three years in Tromsø and Vesterålen, in Northern Norway. The surviving material from the field tests, along with plants raised from the original seed lots, were subjected to freezing tests. LT50 values varied across cultivars and materials. Many genes coding for transcription factors and proteins known to play an important role in freezing tolerance, like dehydrins, c-repeat binding factors, and late embryogenesis abundant proteins were upregulated with decreasing temperatures. Moreover, genes associated with glycolysis/gluconeogenesis, TCA cycle, glutathione metabolism, proteasome pathways and genes encoding autophagy-related proteins, plasma membrane-associated proteins, sugar and amino acid transporters had elevated expression in field survivors compared to plants raised from the original material. The lower freezing stress tolerance of field survivors despite the elevated expression of several stress-responsive genes might be due to a combination of selection in the field and the age effect. Furthermore, differences in freezing stress response between northern and southern adapted cultivars and surviving material from two field trial locations are discussed.
Authors
Thomas Georges A Bawin Marte Marie Fossum Ranvik Sigridur Dalmannsdottir Egle Norkeviciene Rita Armonienė Erik Alexandersson Laura Elina JaakolaAbstract
Climate change is increasingly affecting agricultural systems, impacting the productivity and digestibility of forage crops that are essential for livestock feed. Understanding how forage crops respond to temperature is crucial for optimizing growth and nutritional value. Remote sensing technologies offer promising tools for monitoring plant health and predicting forage quality. As part of the project UPSCALE, this study examines the growth and spectral response of Northern and Southern cultivars under different temperature regimes. Two red clover (ʻGandalfʼ from Norway and ʻVytisʼ from Lithuania) and two timothy (ʻNorengʼ from Norway and ʻJauniaiʼ from Lithuania) cultivars were grown at controlled temperatures of 12, 15, and 18°C. A total of 168 pots (10L, ~30 plants per pot) were maintained in climate-controlled chambers at The Climate Laboratory, UiT, Tromsø. Plant growth was monitored using the PlantEye F600, providing 3D models, biomass, height, leaf area index, and stress indices (NDVI, NPCI, PSRI). Destructive sampling was conducted at three stages: pre-flowering, post-flowering, and at the end of the experiment. Leaves were scanned using Specim FX10e (VNIR) and FX17e (SWIR) hyperspectral cameras before drying for chemical analysis. Results showed distinct growth differences among the cultivars. Clovers increased in height and biomass with rising temperatures, though ʻGandalfʼ consistently yielded less biomass. Timothy ʻJauniaiʼ followed a similar trend to the clovers, while cultivar ʻNorengʼ had optimal growth at 15°C. Spectral indices did not reveal significant contrasts; ongoing hyperspectral analysis may provide further insights. The upcoming chemical analysis will integrate with hyperspectral data to identify lignin signatures for assessing forage digestibility. These findings contribute to a deeper understanding of how forage crops respond to temperature variations, to select cultivars with optimal growth and digestibility in the face of climate change.