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.
2008
Sammendrag
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.
Sammendrag
Produksjonsklare planter er planter med ferdig utviklete blomsteranlegg, som kan drives og gi avling 2 " 3 mnd. etter planting. Gartnerhallen vil starte produksjon av slike planter av jordbær og bringebær. For å oppnå en tilfredsstillende kvalitet, må det skaffes ny kunnskap om vekstfysiologien hos jordbær og bringebær, for derigjennom å utvikle nye metoder og produksjonssystemer hos Gartnerhallens planteprodusenter. I 2006 ble det derfor etablert et 4-årig brukerstyrt prosjekt i regi av Gartnerhallen, med Bioforsk og UMB som samarbeidspartnere. Her vil vi presentere vekstfysiologiske resultater fra forsøk under kontrollerte klimaforhold med bringebærsorten "Glen Ample" (Sønsteby & Heide, 2008).
Forfattere
Anna Martha Elgersma Shivcharn S. Dhillion Arnold Arnoldussen Josef Fanta Eva BoucnikovaSammendrag
Det er ikke registrert sammendrag
Sammendrag
Quota regulations that prevent output expansion of farms and reallocation of output between farms can cause lower growth in output and productivity. The aim of this study was to explain the output growth rate of Norwegian dairy farms since 1976, and to decompose it into output, input, socioeconomic and technical change components. Instead of using the standard distance function approach for multi-output technologies, we use a growth rate formulation, which automatically removes the farm-specific effects. This formulation also helps to impose non-negativity constraints on marginal products of inputs (input elasticities), which are often violated for many observations, especially when flexible functional forms are used. The farm-level panel data cover three periods: before the quota scheme was introduced (1976-1982); the period with the most output-restricting quota scheme (1983-1996); and the period with a more flexible quota scheme (from 1997 onwards). Results show that the milk quota regulations had a significant constraining effect on output growth, in particular on milk output in the period 1983-1996. Furthermore, the output mix has shifted towards meat production for the average farm. What emerges from this study is that output growth and technical change are negatively influenced by policy aims where productive performance has not been the primary objective, and that there is scope for increased farm growth if the quota regime is liberalised.
Sammendrag
Phytophthora infestans is an important pathogen on potato and tomato during the winter seasons in the north of Vietnam and all the year around in Lam Dong province in the south of Vietnam. Data from earlier studies of isolates of P. infestans collected in 2002-2003 showed that the P. infestans population on tomato and potato from Vietnam still consist of the "old" population. However preliminary studies of P. infestans samples from 2007 indicate that this situation has started to change. Data from aggressiveness tests of P. infestans isolates on tomato and potato showed that the majority of isolates collected from tomato could not infect potato. All tested isolates originating from potato infected both hosts. From 2005-2007, field experiments in tomato and potato using IPM strategies for controlling late blight have been carried out in Lam Dong province and in Hanoi area (north of Vietnam). In these experiments, cultivars with different levels of late blight resistance and different fungicide dosages have been tested. Simple forecasting methods and sanitation procedures were also included in some of the experiments. In Lam Dong, strategies including 7 days fixed spray intervals with full dose of the fungicide mancozeb did not control late blight properly in tomato, and all 4 tomato experiments were terminated early. In the potato experiments use of a more modern fungicide could control late blight using reduced dosages. In the tomato experiments in the north no natural infection of late blight occurred during the experimental period.
Sammendrag
Studies regarding the environmental impact of engineered nanoparticles (ENPs) are hampered by the lack of tools to localize and quantify ENPs in water, sediments, soils, and organisms. Neutron activation of mineral ENPs offers the possibility of labeling ENPs in a way that avoids surface modification and permits both localization and quantification within a matrix or an organism. Time-course experiments in vivo also may be conducted with small organisms to study metabolism and exposure, two aspects currently lacking in ecotoxicological knowledge about ENPs. The present report explains some of the prerequisites and advantages of neutron activation as a tool for studying ENPs in environmental samples and ecologically relevant organisms, and it demonstrates the suitability of neutron activation for Ag, Co/Co3O4, and CeO2 nanoparticles. In a preliminary experiment with the earthworm Eisenia fetida, the dietary uptake and excretion of a Co nanopowder (average particle size, 4 nm; surface area, 59 m(2)/g) were studied. Cobalt ENPs were taken up to a high extent during 7 d of exposure (concentration ratios of 0.16-0.20 relative to the ENP concentration in horse manure) and were largely retained within the worms for a period of eight weeks, with less than 20% of absorbed ENPs being excreted. Following dissection of the worms, Co-60 was detected in spermatogenic cells, cocoons, and blood using scintillation counting and autoradiography. The experimental opportunities that neutron activation of ENPs offer are discussed.
Forfattere
Ricardo Holgado Christer MagnussonSammendrag
El Altiplano es una de las areas mas pobladas en el mundo. Localizada a una altitud de 3500 " 4000 m, las bajas temperaturas restringe la producción de hortalizas a campo abierto. Por lo cual la major parte de hortalizas son producidas en invernaderos rústicos (carpas solares), fabricados con material local y con techos de plasticos transparente. NGOs en la region Andina han recomendado el cultivo de hortalizas para consumo y comercialización, con el proposito de incrementar y balancear la dieta alimenticia e incrementar los ingresos de los agricultores. Nemátodos fitoparásitos o el escaso manejo de estos limitan frecuentemente la producción en los invernaderos. La universidad Catolica Boliviana, tiene sus Unidades Académicas Campesinas (UAC) en el area rural dedicadas a la enseñanza practica a personas con escasos recursos, quienes, después de su formación profesional puedan contribuir al desarrollo de sus comunidades de origen. Bioforsk ha participado en el desarrollo y fortalecimiento de las bases cientificas en Nematologia de Plantas en UAC-Tiahuanaco. Agricultores en Tiahuanaco experimentaban bajos rendimientos en la producción de hortalizas. Un muestreo de nemátodos parásitos de plantas se realizo para dar apoyo a los agricultores de esta area. Muestras de suelo y plantas se recolectaron en 1999. En Todas las muestras se encontraron nemátodos parásitos de plantas. Veinticuatro muestras conteniendo suelo y plantas provienen de papa (Solanum spp.) y otros cultivos andinos. Diecisiete muestras fueron de invernaderos rústicos. Veintiun generos de nemátodos parásitos de plantas se encontraron. Los mas frecuentes fueron nemátodo del quiste de la papa Globodera rostochiensis y el nemátodo del rosario Naccobus sp. (54 %), seguidos por el nemátodo de las lesiones Pratylenchus spp., nemátodo espiral Helicotylenchus sp. Tylenchus sensu lato(41 %), nemátodo del anillo Criconemella sp. (34 %), stunt nemátodos Tylenchorhynchus spp. (29 %) y por ultimo el nemátodo agallador Meloidogyne sp. (19 %). El studio indica que nemátodos fitoparásitos tienen un efecto drastico en el rendimiento y la producción de hortalizas.
Redaktører
Tor Håkon Sivertsen Arne Oddvar Skjelvåg Simone Orlandini Mannava V.K. Sivakumar Josef Eitzinger Pavol Nejedlik Vesselin Alexandrov Leonidas Toulios Pierluigi Calanca Robert Stefanski Raymond Motha Mduduzi Gamedze Miroslav Trnka Ward Smith Jan NetlandSammendrag
‘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.
Sammendrag
Three unsprayed coffee farms (farm 1, 2 and 3) were studied for the natural occurrence of the insect pathogenic fungus Beauveria bassiana in Hypothenemus hampei populations throughout the rainy season of 2004 (July-November) and 2005 (July-December). B. bassiana infections were found during most sampling dates in both years, on all three farms. The B. bassiana infection levels were higher in 2005 than in 2004 with mean prevalence of 12.1 % and 2.7%, respectively. No consistent significant differences in infection level between farms were found in any of the years. B. bassiana infection levels fluctuated widely throughout the season, and peaked at 13.5% on farm 3 in 2004 and at 44.0% on farm 1 in 2005. The H. hampei population was significantly higher in 2004 than in 2005, with 6.9% of the berries infested in 2004 and only 0.7% in 2005. In both years, the H. hampei infestation level was significantly higher on farm 2. No consistent significant differences in H. hampei infestation levels were found between sampling dates on any of the farms. H. hampei infestation levels fluctuated throughout both seasons, and peaked at 15.3% on farm 2 in 2004 and 2.2% on farm 2 in 2005. No consistent density dependent correlation between H. hampei infestation level and B. bassiana infection level was found. Correlations between climatic conditions and R bassiana or H. hampei were not found. (C) 2007 Elsevier Inc. All rights reserved.
Sammendrag
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.