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.
2011
Forfattere
Anne Kjersti Bakken Åshild T. Randby Peter UdénSammendrag
The objective was to investigate whether the concentration, composition and rumen in sacco degradability of the neutral detergent fibre fraction in forages are affected by preservation method. A mixed crop of timothy, meadow fescue and red clover was preserved as hay, direct-cut or wilted silage at succeeding developmental stages. Pure crops of timothy and perennial ryegrass were preserved as direct-cut silage only. In both grasses and mixed crops, and especially at early phenological stages, restricted silage fermentation after addition of formic acid caused considerable degradation of ash-free neutral detergent fibre (aNDFom). In direct-cut mixed and pure grass silages, the aNDFom content was 50 and 40 g/kg DM lower than in the respective fresh crops. For grasses, the indigestible proportion of aNDFom was higher in silages than in the corresponding herbage. There were few differences in fibre characteristics between restrictedly fermented silages and silages that were extensively fermented due to inoculation with lactic acid bacteria. Irrespective of crop developmental stage, wilting for silage production and drying to hay led to a considerable increase in the aNDFom content, amounting to nearly 90 g/kg DM for the grass-clover crop. The increase was possibly caused by formation of N compounds which were recovered in the degradable fraction of aNDFom and of indegradable products. Ensiling reversed effects of wilting on aNDFom. Results indicate that predictions of feed intake or structural value of forages based on total content and degradability of aNDFom may be biased by changes in the fibre fraction during preservation.
Sammendrag
The strawberry blossom weevil (Anthonomus rubi) is a small univoltine weevil severing the flower buds of strawberry and some other species of Rosaceae in order to provide for its offspring. The damage made by the weevil in Norwegian strawberry fields is increasing as chemical control is proving difficult and large numbers of weevils are observed in yet more districts. To develop new strategies to control the weevil, a better understanding of its biology is needed. Most studies of A. rubi have focused on the period when bud damage is done, whilst less is known about the ecology and behaviour at other times of the year. The literature on overwintering habits indicates that in the UK A. rubi leaves the strawberry field to overwinter, while elsewhere in Europe they may stay in the field. In a Norwegian project we used emergence traps and laboratory inspection of individual plants to search for weevils in the late autumn and early spring. In fields with weevil problems, we found significant numbers of A. rubi, typically 1-5 per plant (average of 10 plants) shortly before snow fall, and similar numbers early in the spring. The overall sex ratio was close to 1:1. We also found large numbers of overwintering weevils in plants that had been terminated with glyphosate, indicating that weevils were not repelled by dying plants as overwintering habitat. This considerable presence of weevils in the crop throughout the year could increase the chance of succeeding with alternative methods like microbiological control or mass trapping. It also implies that terminated (glyphosate-treated etc) fields should be ploughed on cool days in the autumn (A. rubi cannot fly at low temperatures) to bury the weevils, and not be left alone till late in the spring for weevils to escape.
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Forfattere
Tim J. Mullin Bengt Andersson Jean-Charles Bastien Jean Beaulieu Rowland D. Burdon W.S. Dvorak John N. King T. Kondo Jodie Krakowski Steve J. Lee Steve E. McKeand Luc Pâques Annie Raffin John H. Russel Tore Skrøppa Michael Stoehr Alvin YanchukSammendrag
This chapter reviews the historical context, economic importance, objectives and achievements to-date for many of the more important conifers undergoing domestication through genetic improvement programmes around the world. These provide examples of the context in which genomic technologies will have an impact in forestry. Unlike many other crop plants and livestock animals, forest trees have only been exposed to a few cycles of breeding and selection, and most retain very large amounts of genetic variation in natural populations. These factors present both opportunities and hurdles in the effective application of genomic technologies to existing operational breeding programmes.
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Colletotrichum acutatum causes black spot in strawberry (Fragaria × ananassa), but it has also been isolated from 30 other cultivated and non-cultivated plant species in Norway, including almost all fruit and berry crops. Bitter rot, which is caused by C. acutatum, is a severe disease in sweet and sour cherry and apple. We have studied the possibility of cross infection of isolates from other hosts and the potential aggressiveness of these isolates on strawberry. Molecular analyses (AFLP) have shown that isolates collected in Norway could be separated into three major phylogenetic groups in which isolates collected from either Prunus spp., Malus domestica or Fragaria × ananassa predominated. Experiments were carried out under laboratory, greenhouse and field conditions, and strawberry fruits, leaves and stolons were inoculated. All experiments showed that isolates originating from the Fragaria group was much more aggressive than those from the other two groups. If detached strawberry fruits were wounded at time of inoculation, isolates from all groups developed black spot, but disease development went much slower for isolates from the Prunus or Malus groups. If not wounded, there was no or hardly any disease development caused by isolates from the latter two groups. On whole plants inoculated in the greenhouse, isolates in the Fragaria group developed an incidence of 27 to 28 % flower and fruit infections compared to 0 to 4 % for isolates from the other two groups. Under field conditions, Fragaria group isolates developed 50 to 70 % more infected fruit than the others at harvest. On stolons, we inoculated by wounding, and differences in aggressiveness between isolates were only minor. On strawberry leaf laminas, we observed that the ability to colonize the leaf surface was much larger for isolates from the Fragaria group compared to those from the other two groups. However, planting healthy strawberry transplants adjacent to infected sweet cherry trees resulted in latent infections of C. acutatum on strawberry leaves (but no visible infections on fruits), indicating that cross infection between host species may occur under field conditions.
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The main task of the C1-Dep-22(SI) action was to compare national throughfall collectors with a harmonized collector which was designed according to the requirements of the WMO. The action spread onthe took place in very different climate zones and vegetation, and included a very different types of national collectors with different sampling procedures. The number of harmonized throughfall collectors was 30 for all participants. The spatial arrangement in the plot, sampling times, sampling and cleaning procedures, bulking of the subsamples and chemical analysis procedures were in all cases the national procedures. The time when the precipitation was in the form of snow was excluded from the sampling periods. The associated beneficiaries reported the amounts of the precipitation per collector and the results from chemical analysis per pooled sample. The measured quantities were compared for different types of forest or main tree species. The deviations between collectors were lower in the plots with the broadleaf trees than in the plots with conifers as the main tree species. The median deviations for conifers and for broadleaves trees is not significantly different from zero. Except in a few cases, a good agreement in the amount of precipitation was found between the national and harmonized collectors for both throughfall and bulk precipitation. In a few incidents this was not the case but we assume that where this was not the case, this was due to happened in extreme weather conditions e. g. heavy storms. Also good agreement was also found within for the chemical composition of the solutions, gathered with different types of collectors. Again, there were some deviations limited to on single occasions. It was found that the harmonized collectors were attractive to birds and thus a bird ring is a must in this (white) -coloured version of the collector. Chemical analysis (chemical composition) together with the collected amount of the solution depends on give the total deposition values. It was made a close up to the deposition values of ammonium-nitrogen, nitrate-nitrogen and sulphate-sulphur were compared in detail. For ammonium-nitrogen no bigger difference was found for the one-year deposition values except in one case what which turned out to be almost certainly a consequence of birds activity. Differences in all other cases were no more than 0.3 g m-2 yr-1. For nitrate-nitrogen smaller deviations were found but in none of the case was the difference was in total annual deposition higher than 0.3 g m-2 yr-1. For sulphate-sulphur good agreement was found for all associated beneficiaries except two. One of the Possible reasons could be in the difference of in the ability in collecting dry deposition and/or the total area which contributes to the capturing area for dry deposition. Despite their heterogeneity and some unlack of adaptation for representative sampling at the plot scale, the national devices for throughfall collection gave comparable results infor throughfall deposition to the harmonized, optimal collectors. In conclusion national throughfall collection devices can be maintained to ensure the continuity of the time series in deposition monitoring. And to improve the harmonized collector even more, problems with the possible blockages of the tube at the bottom of the funnel because of debris should be solved.
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