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.
2017
Authors
Merete Wiken Dees Simeon Rossmann Monica Skogen Vinh Hong Le Arnaud Lefrancois Abdelhameed Elameen Borghild Glorvigen Alison K. Lees Jan van der Wolf May Bente BrurbergAbstract
No abstract has been registered
Abstract
During August 2013, white-grayish lesions, typical of Sclerotinia stem rot, had developed around leaf axils on the stems of turnip rape ‘Pepita’ in a field at the NIBIO research station Apelsvoll in Oppland County, Norway. Sclerotia were collected from inside infected turnip rape stubble and from harvested seeds, surface sterilized, bisected, and placed onto potato dextrose agar (PDA). Following 1 to 2 days incubation at 20°C, fast-growing white mycelium characteristic of Sclerotinia was observed, and within 5 to 7 days, new sclerotia had started to develop. Sclerotia size and growing pattern although variable was characteristic of S. sclerotiorum. DNA extraction, PCR amplification, and sequencing of the ITS regions of the rDNA was then carried out for 20 isolates. BLASTn analysis of 475 bp amplicons showed that 15 isolates were S. sclerotiorum, while five were identified as S. subarctica (previously called Sclerotinia sp 1; Holst-Jensen et al. 1998; Winton et al. 2006, 2007), with 100% identity to a U.K. S. subarctica isolate (Clarkson et al. 2010). A representative ITS region sequence was deposited in GenBank (accession no. KX929095). The identity of the S. subarctica isolates was further confirmed by the lack of a 304-bp intron in the LSU rDNA compared with S. sclerotiorum (Holst-Jensen et al. 1998), which was visualized by PCR amplification and gel electrophoresis. Sclerotia of two S. subarctica isolates were placed on PDA and incubated for 7 days. Agar plugs of actively growing mycelium were used for the pathogenicity testing of spring oilseed rape plants (‘Mosaik’) in the greenhouse. Plants were inoculated at growth stage BBCH 57/59 (preflowering) and BBCH 64 (40% of flowers open) by attaching two PDA plugs of actively growing mycelium per main stems with small needles, using four plants per treatment. Noninoculated PDA agar plugs were attached to the control plants. The experiment was repeated three times. Symptoms typical of stem rot appeared after 1 to 2 weeks of incubation at 16 to 20°C, 100% relative humidity. Stems started to develop white lesions with fluffy mycelium around the inoculation sites. Control plants did not show the characteristic symptoms for Sclerotinia infection. After senescence of the plants, sclerotia were collected from inside the stems and cultured on PDA. White mycelium started to grow after 1 to 2 days and new sclerotia were formed within 7 days, similar to the ones used for producing the initial isolate. Brassica oil seed crops are cultivated as important break crops in the cereal-based production system in Norway and can be severely affected by Sclerotinia stem rot. The disease is observed in all regions where Brassica oil seed crops are grown, and in severe cases, a reduction in oilseed yield of 25% has been recorded in untreated control treatments of fungicide trials. Although S. subarctica has been previously reported on wild hosts (Holst-Jensen et al. 1998), this is the first report of the pathogen on a crop plant in Norway. In the United Kingdom, Clarkson et al. (2010) demonstrated pathogenicity of S. subarctica isolated from Ranunculus acris on oilseed rape. As symptoms for S. subarctica and S. sclerotiorum are indistinguishable, S. subarctica might be present undetected in many farmer fields.
Abstract
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Authors
Mette Thomsen Erlend Indergård Belachew Asalf Tadesse Pia Heltoft Thomsen Anne-Berit Wold Berit Nordskog Gerd Guren Johannes Dyste Hanne LarsenAbstract
Optimization of produce quality and storage conditions to reduce loss during long-term storage of root vegetables in Norway (OPTIROOT, 2016-2019) Authors: Thomsen, M.G., Indergaard, E., Asalf, B., Heltoft, P., Wold, A.B., Nordskog, B., Guren, G, Dyste, J. & Larsen, H. Author’s affiliation: Key words: carrot, swede, celeriac, storage technology, diseases, physiological disorder, packaging, nutrition Reducing yield loss along the supply chains is important for resource sustainability in vegetable production. Norwegian root vegetables are typically stored 6 to 8 months before consumption, often resulting in 20-30% loss post harvest. In OptiRoot 26 producers, refrigeration-technology companies, sensor developer, grower’s organisation, agricultural advisory service, and four research institutes are cooperating and conducting research to improve storage quality of carrot, swede and celeriac. The research focuses on: i) Fertilizer/Boron deficiency affects the storage quality of root vegetables and amount, methods of application, and timing of boron are studied in swede and celeriac. ii) Interaction between storage conditions/functions and produce quality of the root vegetables through mapping of technical features of 27 storages. The storage conditions recorded are relative humidity, air movement, temperature in boxes and storages, and physical features of storages. In addition, the physiological and health status of the produces are assessed one week before harvest, postharvest and post-storage. The prevalence of fungal diseases or disorders varied from region to region and between storages. iii) Effects of pre-storage wound healing are tested using seven different temperature strategies (direct to 0° C vs. down 0.2° C per day vs. 1° C per day) and low/high humidity in carrot (2016/17/18), celeriac and swede (2017/18/19). Preliminary results show that wound healing reduced loss due to fungal infections in carrot iv) CO2 concentration, temperature and relative humidity were recorded over time inside carrot storage bin liners with different numbers of perforations. An initial screening indicated a positive correlation between number of holes and number of fresh roots. As a post storage method, coating of swede with chitosan oligomers will be tested to inhibit growth of post-harvest pathogens. In conclusion, OptiRoot have gained good progress and promising preliminary results by connecting data on biology and technology for reduction of loss during long-term storage.
Authors
Andrea FickeAbstract
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Authors
Andrea FickeAbstract
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Authors
Nina Trandem Arne Stensvand Joséphine Rehnfeldt Karin Westrum Dan H. Christensen Aksel Døving Jan Karstein HenriksenAbstract
No abstract has been registered