Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2007
Forfattere
Arne Stensvand Heidi Udnes Aamot Gunn Mari Strømeng Sonja Klemsdal Jorunn Børve Venche TalgøSammendrag
Foredrag om omfang og viktigheit Colletotrichum acutatum i norsk frukt- og bærdyrking
Sammendrag
In Norway, Nordmann (Abies nordmanniana) and subalpine fir (A. lasiocarpa) are the dominant Christmas tree species and Noble fir (A. procera) the dominant species for bough production. In the spring of 2005 a survey was undertaken to determine the presence of fungi on seeds of these three plant species. Twelve seed samples were tested; five from Nordmann fir, four from subalpine fir and three from Noble fir. The test included seeds produced in Austria (Nordmann fir), Canada (subalpine fir), Georgia (Nordmann fir), Norway (Noble and subalpine fir) and Russia (Nordmann fir). The testing was done in a certified seed laboratory in Norway. One hundred seeds per sample were pre-treated in 1 % NaOCl and plated on potato dextrose agar (PDA), and 100 seeds per sample were pre-treated in H2O2 and plated on water agar (WA). The PDA Petri dishes were incubated for 5 to 7 days at 20 + 2 ºC and the WA Petri dishes for 15 to 19 days at 15 + 2 ºC, both under alternating 12 h NUV-light and 12 h darkness. To date not all of the fungi have been identified, but fungi from several genera have been found: Alternaria, Anthostomella, Aspergillus, Aureobasidium, Botrytis, Caloscypha, Cephalosporium, Chaetomium, Cladosporium, Dictyopolyschema, Epicoccum, Fusarium, Mucor, Penicillium, Phoma, Rhizopus, Trichoderma, and Trichothecium. Caloscypha was only found on one subalpine fir seedlot from Canada and Anthostomella on one subalpine fir seed from Norway. All the other fungi were more commonly found in all the samples. Fusarium species are well known to cause damping off in nurseries, but are not reported to cause problems in production fields. Species of Alternaria, Phoma, Botrytis and Trichothecium can damage seedlings. Anthostomella conorum is reported on cone scales of pine (Pinus spp.), but is not described as pathogenic. Aureobasidium is described as a saprophytic or weakly parasitic cosmopolitan fungal genus. Aureobasidium sp. is commonly found in Norway on buds of subalpine fir which fail to open in spring, and it will therefore be included in a pathogenicity test.
Sammendrag
Den middpatogene soppen Neozygites floridana er en viktig naturlig fiende for veksthusspinn - midden, Tetranychus urticae. Plantevernmidler, spesielt soppmidler, kan hemme denne nyttesoppen. Dette bør det tas hensyn til når en sprøyter mot soppsykdommer i jordbær og i andre kulturer hvor veksthusspinnmidden er et problematisk skadedyr.
Forfattere
May Bente Brurberg Arne Hermansen Abdelhameed Elameen Vinh Hong Le Björn Andersson Asko Hannukkala Bent J Nielsen Jens G Hansen Jonathan YuenSammendrag
Studies of genetic variation of the late blight pathogen among isolates collected in 2003 in the Nordic countries were presented
Forfattere
May Bente Brurberg Arne Hermansen Abdelhameed Elameen Vinh Hong Le Björn Andersson Asko Hannukkala Bent Nielsen Jens G Hansen Jens G YuenSammendrag
Phytophthora infestans was isolated from potato leaves collected from 200 fields located in different parts of Finland, Denmark, Sweden and Norway in 2003. Sampling was carried out relatively late in the epidemic. The SSR analysis was carried out in Norway. Nine SSR markers were tested; Pi4B, Pi4G, PiG11, Pi02, Pi04, Pi16, Pi26, Pi33 and D13. Based on only 7 SSR markers 190 genotypes were found. Six genotypes occurred twice and one genotype occurred six times. The high genetic variation indicates sexual reproduction in the Nordic late blight population
Sammendrag
A review on the most common potato-infecting viruses was given. The following viruses were described: Potato virus X, Potato virus Y, Potato virus M, Potato virus S, Potato moptop virus and Tobacco rattle virus. The way each virus is transmitted as well as strategies to prevent aphid transmission of viruses was explained
Sammendrag
Poinsettia (Euphorbia pulcherrima Willd. Ex Klotzsch), is a contemporary symbol of Christmas in most parts of the world. Today, Europe and North America represent the largest volume of production and sales, but demand is growing quickly in the other regions as poinsettia becomes more popular each year. In Norway, poinsettia is one of the most important pot plants, with a yearly production close to 6 million plants. Its ornamental value and innovation potential have laid the foundation for extensive research in Norway and elsewhere. Two viruses i.e. poinsettia mosaic virus (PnMV) and poinsettia cryptic virus (PnCV) can cause diseases in modern poinsettia cultivars. PnMV gives visible symptoms in poinsettia during parts of the growing season. Growers show great interest in the potential benefits of growing PnMV-free poinsettias. Traditionally, PnMV-free poinsettia plants were obtained by in vitro culture of apical meristems. However, this is a time-consuming method and the regenerated new PnMV-free poinsettia has sometimes lost the branching characteristic which is important for poinsettia. We have therefore developed an Agrobacterium-mediated transformation approach for poinsettia. Using this method, we have produced transgenic poinsettia with improved resistance against PnMV by expressing three hairpin (hp) RNA gene constructs which targeted various regions of the virus genome. Molecular analyses have confirmed the stable integration of transgenes into the poinsettia genome. This is the first report describing Agrobacterium-mediated transformation of poinsettia. The PnMV resistant transgenic poinsettia lines produced are of commercial potential. The methodology developed could also facilitate the further improvement of this ornamental plant with the aims of enhancing its disease resistance, quality traits, desirable colour and ornamental value. We have also transformed N. benthemiana to reveal the relationship of different vector constructs and the RNA silencing mediated PnMV resistance. This result will imrpove our understanding of RNA silencing mediated resistance through genetic engineering.
Sammendrag
The prediction of infection periods for lettuce downy mildew (Bremia lactucae) is based on the assumption that spores are produced at night and released in the early morning. The divergent light conditions at Nordic latitudes might affect both sporulation and spore release. Therefore, we monitored release of B. lactucae spores in relation to the climatic conditions in lettuce fields to evaluate the performance of existing forecasting models in timing of fungicide applications for management of lettuce downy mildew in Norway. In 2005, epidemics were created at two field locations that had no previous lettuce production, and a total of 59 days of spore trapping permitted the study of spore release under natural conditions. Sporulation events were compared to predicted spore production events in Modell-Analys (MA). At the two locations, 76 % and 74 % of the spores were trapped between 08.00 and 16.00, respectively. Spore concentration icreased with decreasing relative humidity (RH), ofting coinciding with increasing solar radiation and temperature. Spore production events predicted by MA were correct at 66 % of the days. However, when the criteria for spore production were adjusted, 78 % of the days were correctly predicted.
Sammendrag
Several models for prediction of infection periods for lettuce downy mildew (Bremia lactucae) are based on the assumption that spores are produced at night and released in the early morning. The divergent light conditions at Nordic latitudes might affect both sporulation and spore release. Therefore, during the period 2001 to 2005 a total of 13 field trials were established in late season lettuce fields to evaluate efficacy of fungicide applications made according to the models PlantPlus (PP) and Modell-Analys (MA) in Norway. Disease severity varied from 0 to 89.4 % in unsprayed control plots at harvest. Fungicide treatments had a significant effect compared to untreated control in all but two of the field trials with disease incidence over 1 % at harvest. Fungicide applications at 10-day intervals and according to PP and MA resulted in an average of 3, 2.5 and 3.3 applications, respectively. There were no significant differences in disease severity at harvest between treatments according to 10-day interval, PP and MA for any of the field trials. Epidemics were created at two field locations that had no previous lettuce production, and a total of 59 days of spore trapping permitted the study of spore release under natural conditions. Spore production events predicted by MA were correct at 66 % of the days. However, when adjusting the criteria for spore production, 78 % of the days were correctly predicted.
Sammendrag
Forsøk med varsling av salatbladskimmel i perioden 2001-2005 ble presentert