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.
2011
Authors
Mette Vaarst Christoph Winckler Stephen Roderick Gidi Smolders Silvia Ivemeyer Jan Brinkman Cecilie Marie Mejdell Lindsay k Whistance Pip Nicholas Michael Walkenhorst Christine Leeb Solveig March Britt IF Henriksen Elisabeth Stöger Elisabeth Gratzer Berit Hansen Johann HuberAbstract
No abstract has been registered
Authors
Matthias Zielke Arne Hermansen John Beck JensenAbstract
No abstract has been registered
Authors
May Sæthre I. Godonou Trond Hofsvang Ghislain Tchoromi Tepa-Yotto B. JamesAbstract
No abstract has been registered
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Abstract
Dieback of European ash (Fraxinus excelsior), caused by the ascomycete Hymenoscyphus pseudoalbidus (anamorph Chalara fraxinea), started around 1992 in Poland and has since then spread over large geographical areas. By November 2010, the disease had been recorded in 22 European countries. The gradual expansion and high intensity of the ash dieback epidemic in Europe may suggest that H. pseudoalbidus is an invasive alien organism. In Norway, ash dieback was first reported in spring 2008, and a survey in early summer of the same year revealed that the disease had spread over large parts of the southern and eastern regions of the country. The distance from the southernmost to the northernmost infected stands was, at that time, about 400 km. Some old necrotic lesions were also observed, indicating that the ash dieback pathogen is likely to have been present in Norway since at least 2006. In 2009, a spore sampler was installed in a diseased ash stand at Ås, South-Eastern Norway. Sampling started in late July and continued until late September. Large numbers of ascospores resembling those of H. pseudoalbidus were observed, with the maximum number of spores occurring from the end of July to mid-August. The deposition of ascospores occurred mainly between 6 and 8 a.m. Ascospores are most likely to be the primary source initiating host infections and responsible for the rapid recent spread of H. pseudoalbidus in Europe.
Abstract
A high through-put Abbreviated liquid Chromatography Mass Spectrometric (ACMS) method was used to assess the relative influence of genotype and temperature on polyphenol composition in cloudberries. Principal component analysis (PCA) plots of the collated ACMS data showed a separation between crosses based on their female parents (Nyby or Fjellgull). Crosses with Nyby as female parent had higher relative levels of masses assignable to certain ellagitannin derivatives. Crosses with Fjellgull had higher levels of distinctive masses assignable to quercetin derivatives (including a hydroxy-3-methylglutaroyl hexose derivative not previously identified in cloudberry) and anthocyanin-derivatives. There was also a separation between samples grown at lower and higher temperatures, which was driven by m/z signals associated with ellagitannins and notably a major component, Sanguiin H-6. Therefore, abbreviated MS techniques can discern genetic and/or environmental influences in polyphenol composition and can quickly assess quality in breeding programmes or in response to environmental changes.
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No abstract has been registered
Abstract
Three primary causal agents are involved in the leaf blotch disease (LBD) complex of Norwegian winter and spring wheat: Phaesophaeria nodorum, Mycospaerella tritici, and Pyrenophora drechslera-tritici. The dynamics of symptom development, similarity of symptoms caused by each agent, and confounding of disease symptoms by leaf senescence interfere with accurate assessment of disease. Empirical and regression models for disease and yield loss forecasting are only as good as the data upon which they are based. Accurately describing the relationship between symptoms and yield loss is therefore critical to meaningful economic thresholds for management decisions and advisory systems. A general guideline for yield loss and disease severity has been described as 1% yield loss per 1% disease severity on the flag leaf at BBCH stage 70-75 (King et al., 1983). However, several years of field trials in Norway indicate that disease severity can increase exponentially during these developmental stages, making disease severity highly dependent upon time of assessment. LBD severity on flag leaves of the spring wheat variety ‘Bjarne’ at two different locations in 2010 varied during the above BBCH stages from 27% to 44% and from 4.45% to 23.2%. Different varieties may compensate differently for loss of photosynthetic area on the flag leaf due to leaf blotch pathogens, rendering the general guide line for yield loss inaccurate. Preliminary studies in Norway indicated that the relation between yield reduction (TKW) and disease severity of the flag leaf differed substantially for five different spring varieties and ranged from 0.03 to 1.4 at BBCH 70 and from 0.8 to 4.1 at BBCH 75, at one field site at Aas, Norway in 2010. The causes of the observed variation in the relationship between flag leaf severity and yield reduction are poorly understood. Effects of other diseases are not accounted for by leaf blotch assessments, nor are fungicides applied to reference plots necessarily eliminating all disease effects on yield. Timing of assessments may be as critical as the accuracy of the assessments; making it necessary to time the assessments properly, and distinguish clearly between leaf senescence and leaf blotch symptoms.
Authors
May Sæthre I. Godonou S. Leclercq G.T. Yoto B JamesAbstract
No abstract has been registered