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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.

2008

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Abstract

Representative European wheat cultivars were tested under quarantine containment for their susceptibility to Tilletia indica, the cause of Karnal bunt of wheat. Fifteen winter and 15 spring wheat (Triticum aestivum) and 11 durum wheat (Triticum durum) cultivars were inoculated by boot injection just prior to ear emergence to test their physiological susceptibility. Selected cultivars were then re-tested by spray inoculation after ear emergence to determine their morphological susceptibility, which is a better predictor of field susceptibility. At maturity, the ears and seeds were assessed for incidence and severity of disease. For the physiological susceptibility tests, 13/15 winter wheat cultivars were infected and the percentage of infected seeds ranged from 1 to 32%. For spring cultivars, 13/15 cultivars were infected and the percentage of infected seeds ranged from 1 to 48%. For the durum cultivars, 9/11 were infected and the percentage of infected seeds ranged from 2 to 95%. Across all cultivars, 35/41 were infected. Based on historical Karnal bunt susceptibility categories using coefficients of infection, one cultivar was classed as highly susceptible, three as susceptible, 11 as moderately susceptible, 20 as resistant and only six as highly resistant. The spray-inoculation morphological susceptibility tests broadly confirmed the physiological susceptibility results, although lower levels of infection were observed. Overall, the range of susceptibility was similar to that found in cultivars grown in Karnal bunt affected countries. The results demonstrate that European wheat cultivars are susceptible to T. indica and thus could potentially support the establishment of T. indica if introduced into Europe.

Abstract

Due to a late harvesting season compared to that found in other European countries, the sweet cherry industry in Norway is now expanding, aiming for export markets. Cultivars producing high quality fruit that ripen late (late July and throughout August) and that are suitable to grow in high density production systems are sought. In addition, early ripening cultivars are sought for local marketing in early and middle July. Testing cultivars and advanced selections has been carried out at Ullensvang Research Centre since 1959. During the last decade, 130 cultivars and advanced selections have been included in the testing program. Important parameters like fruit size, fruit firmness, low fruit cracking, high and precocious yield, fresh appearance and good flavour have been evaluated. Based on the results from this testing program, the following cultivars are currently recommended: a) for early season: `Burlat", `Moreau" and `Merchant", b) for mid-season: `Giorgia", `Chelan", `Samba", `Techlovan" and `Van", c) for late season: `Lapins", `Kordia", `Regina" and `Sweetheart".

Abstract

Some high density sweet cherry orchards in Norway suffer from decay of trees resulting in death or reduced vigour of trees. A survey monitoring healthy and infected trees from several orchards found differences between cultivars and rootstocks in sensitivity of tree decay. In order to investigate this cherry tree decay further, new field trials were established in 2002 with trees of the cultivar Van grafted on the two rootstocks Prunus avium seedling and Colt and trained as central leader trees. Two parallel trials were planted; one in the soil of an old cherry orchard and the other in the soil from agricultural land where no fruit production had been conducted in advance. During the first years significant larger annual vegetative growth measured as trunk girth, annual shoot growth and leaf areas were registered from the trees growing in the virgin soil. In the replanted cherry soil, trees grafted on the rootstock Colt grew more vigorously than the seedling rootstock based on leaf areas and shoot growth measurements. The rootstock Colt may be the answer for avoiding cherry replant diseases.

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Abstract

‘The Symposium on Climate Change and Variability – Agro Meteorological Monitoring and Coping Strategies for Agriculture’ is organized by the Management Committee of COST734’ Impact of Climate Change and Variability on European Agriculture’ and the Commission for Agricultural Meteorology (CAgM) of WMO. The content of the symposium is closely connected to the themes of the working groups of COST734 and the term of reference of the ‘WMO Expert Team on Climate Risks in Vulnerable Areas” The symposium is devoted to the very important issue of agricultural crop production and climate change. The discussion is placed in the light of agro meteorology, in Europe and in the rest of the world. The event will serve as a meeting place between meteorologists and agronomists. The cooperation between these two groups of researchers is important to find optimal mitigation and adaptation strategies with respect to impacts of climate change/variability on agriculture. The book of abstracts for the symposium contains altogether 52 contributions. 26 of the abstracts are oral contributions, and 26 of the abstracts will be presented as posters.

Abstract

An infectious cDNA clone of a Norwegian isolate of Poinsettia mosaic virus (PnMV) was generated. It consisted of 6,098 nucleotides and encoded a polyprotein of 219.5 kDa. Sequence comparisons indicated that this isolate shared 98.6% (nucleotide) and 97.1% (amino acid) identity with the previously sequenced isolate from Germany. RNA transcripts derived from this cDNA were infectious in Nicotiana benthamiana. However, plants did not present typical PnMV symptoms. Furthermore, RNA transcripts from this cDNA clone were not infectious in poinsettia. Serial propagation of this cDNA clone in N. benthamiana plants restored symptom induction in this host but did not re-establish infectivity in poinsettia.

Abstract

The use of traditional preservative treated wood has been highly restricted in recent years, and there is a need to find environmental benign alternatives. Utilisation of naturally durable wood is commonly proposed as an alternative for wood used in above ground applications. Traditionally, heartwood of Scots pine (Pinus sylvestris L.) has been used in constructions prone to biological degradation. However, when utilising the heartwood for solid wood products, one has to consider that the stemwood of Scots pine also comprises non-durable sapwood, and that the heartwood varies with respect to decay resistance. The purpose of this thesis was to study techniques for improved utilisation of natural durability, with special focus on Scots pine heartwood. A study was conducted aiming to describe the variation of heartwood diameter in mature Scots pine...

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Abstract

The effect of night temperature on short day (SD) floral induction has been studied in three June-bearing strawberry cultivars of different geographic origin and compared with yield performance in the cool Nordic environment. At the optimum day temperature of 18 degrees C, the SD flowering response of the cultivars 'Florence' and 'Korona' increased significantly with increasing night temperature from 9 to 18 degrees C, while an optimum was reached at 15 degrees C in the cultivar 'Frida' that is selected under cool-environment conditions in Norway. Also, while saturated flowering response was obtained with 3 weeks of SD treatment at all temperatures in 'Frida', several plants of 'Florence' and 'Korona' failed to initiate flowers at 9 degrees C night temperature even with 5 weeks of SD. The effect of extended SD period was particularly pronounced in 'Florence'. The slow SD floral induction response of 'Florence' was associated with a 2 week delay of anthesis in subsequent long day (LD) conditions at 21 degrees C. Yield performance of the same cultivars during 2 years under field conditions at Nes Hedmark and in North Norway also demonstrated that the yield potential of 'Florence' was not realized under the climatic conditions prevailing at these locations. In both years the yields varied significantly among the cultivars,'Frida' having the highest yields followed by 'Korona', with 'Florence' far below. It is concluded that, in the Nordic environment, autumn (September) night temperatures are obviously suboptimal for yield performance of some June-bearing strawberry cultivars, and that this effect is mediated by autumn temperature effects on flower initiation responses. (C) 2008 Elsevier B.V. All rights reserved.

Abstract

Patterns of tree mortality, rates and type of tree and snag fall, and relationships between snag characteristics and potential wildlife habitat value were estimated for hybrid spruce (Picea glauca (Moench) Voss x engelmannii Parry ex Engelm.) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) in eastcentral British Columbia in order to provide important parameters for deadwood modelling. We sampled 172 snags (52 spruce and 120 fir) for species, size, morphological, and habitat attributes, and used dendroecological techniques on a subsample of these (n = 158) to estimate year of death. Input of snags appeared to occur at a nearly constant rate in these stands. Estimated annual tree fall, including live trees and snags, was 5.3% for hybrid spruce and 6.1% for subalpine fir and stem breakage was more frequent than uprooting. Long-term annual snag fall rates were 4.6% for hybrid spruce and 2.9% for subalpine fir. Discriminant analysis based on time since death correctly classified snags into three decay classes for 85% and 72% of spruce and fir, respectively. Snags that potentially could provide important functions for wildlife habitat were more prevalent in fresh and intermediate classes for hybrid spruce and in intermediate and old classes for subalpine fir. The results provide valuable parameters for further development of deadwood models, which are an important tool for development of best practices for deadwood management.