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.
2002
Sammendrag
Determining the level of pathogenic fungi and other microorganisms during colonization of the host is central in phytopathological studies. A direct way to monitor fungal hyphae within the host is microscopic examination, but chitin and ergosterol-levels are commonly used to indirectly measure the amount of fungus present. Recently real-time PCR technology is being used to follow infection agents in host tissues. We study the molecular basis of host defense responses, using the coniferous host Norway spruce infected with the pathogen Heterobasidion parviporum as the experimental system. This basidiomycete and the closely related pathogen H. annosum are the major root rot causing pathogens in conifers. To screen host material for differential resistance towards H. parviporum, it is a necessity to quantify the fungal colonization of the host tissues. Therefore, we aimed to develop and compare the sensitivity of a real-time PCR to an ergosterol based method for determining the rate of colonization, and applied the methods to rank the infection level of the pathogen on the spruce clones 053 and 589. We developed a quantitative multiplex real-time PCR procedure that reliably detecting down to 1pg H. parviporum DNA and 1ng host DNA. There was a very high correlation between the fungal-biomass/total-biomass and fungal-DNA/total-DNA rankings obtained with ergosterol and real-time PCR, strengthening the credibility of both methods. Based on both ergosterol and real-time PCR, it was clear that the clone 053 was hosting more fungal biomass than clone 589. The results indicate that this real-time procedure can be a useful method to screen different spruce material for their relative resistance to the pathogen H. parviporum.
Forfattere
Ragnar Eltun G. Guttormsen Erling Stubhaug Hugh Riley Lars Olav Brandsæter Richard Meadow Trond M. Henriksen A.K. Løes Anne Kjersti Bakken Åsmund Asdal Trygve S. Aamlid T.A. Breland Trond K. Haraldsen Tore Sveistrup J. Olsen A-C. Wallenhammar A. NykanenSammendrag
Publikasjonen inneheld samandragsartiklar frå avsluttingsseminaret for det stratgiske instituttprogrammet "Næringsforsyning i økologiske dyrkingssystem med lite husdyrgjødsel". Følgjande emne er presentert:1) Gjødslingsvekster som nitrogenkilde ved dyrking av grønnsaker, 2) Oppsummering av erfaringene med bruk av underkulturer og med bruk av planteavklipp som dekkemateriale ved grønnsakdyrking på Kise 1998-2002, 3) Helhetlige metoder for kontroll av ugras og skadedyr i radkulturer ved hjelp av underkultur og plantavklipp, 4) Forgrøder og organiske gjødselslag som næringskilde til korn, 5) Ettervirkning av frøeng i økologiske omløp, 6) Fosfor- og kaliumeffektivitet i bygg og vårhvete: Forskjeller mellom eldre og nyere sorter, 7) Avlingar og jordeigenskapar gjennom seks års økologisk drift i dyrkingssystema på Planteforsk Landvik, Østre Voll, NLH og Planteforsk Kvithamar, 8) Forsøk med økologisk plantedyrking uten husdyr i Danmark, 9) Kvalitetsdyrking av økologisk vårhvete etter kløverrik eng i Sverige, 10) Finske forsøk med næringsforsyning i økologiske dyringssystem med lite eller ingen tilførsel av husdyrgjødsel.
2001
Sammendrag
Two zone sites, i.e. two circular areas with 50 km radius, were established in southern Norway. The zone sites were centred in Tofte (the location of a major pulp mill) and in Drammen (the site of a major timber yard). From June to October 2000, 66 forest blocks were visited, 65 of which were situated within the zone site areas. Samples were collected from 40 forest blocks, especially from wood attacked by wood boring insects. At 34 forest blocks, trees of Scots pine, Pinus sylvestris, or Norway spruce Picea abies were provided as trap-logs for Monochamus spp. This material will be sampled in the survey of 2001. Some samples were also taken from a wood chip pile and from imported wood material. The total number of wood samples analysed for nematodes were 275. Out of these, 214 samples were collected from forest trees, stumps, timber and logging wastes of P. sylvestris and P. abies. Three samples contained nematodes belonging to the genus Bursaphelenchus, but the Pine Wood Nematode (PWN), B. xylophilus, was not detected. Similarly, this nematode was not detected in the 10 samples of wood chips, or in the 25 samples of imported lumber or in the 26 samples of imported solid wood packing material. In order reach the minimal number of 3000 samples within reasonable time, the number of samples for the next survey season of 2001 needs to be increased drastically. To achieve this, the sampling will continue within the existing zone sites, and be extended into new zone sites to be established in 2001.
Sammendrag
Seasonal production of spores (conidia) of Monilinia laxa (Aderh. & Ruhl) Honey on overwintering mummified fruits, blighted flowers and fruit spurs, and newly infected flowers of sweet cherry (Prunus avium L.) was investigated in Norway in 1997-1999. Infected plant parts were incubated in saturated air for 48 h prior to washing in distilled water, followed by a quantification of conidia from the spore suspensions with a light microscope. Mummified fruits or fruit spurs containing blighted flower and leaf parts, placed on the ground in the spring or the preceding autumn, more quickly depleted their inoculum compared to similar plant parts still hanging in trees. Conidia were produced in high numbers on mummified fruits left hanging in trees for 2-3 years after infection. In 1997, the conidial production on fruit mummies in trees was relatively even during the growing season. The year after, the highest sporulation on mummified fruits in trees occurred prior to flowering, and by harvest the sporulation was reduced by 92%. The wet weather that occurred in 1998 probably depleted the inoculum earlier than in 1997, when the summer was drier. The major production of conidia from fruit spurs occurred prior to or around bloom, and very few conidia were observed at harvest. Infected flower and leaf parts attached to the overwintering fruit spurs contained higher numbers of conidia than the fruit spurs themselves. Flowers infected in the spring produced most conidia during the first two months after infection, however, if remaining attached to the fruit spurs, they produced conidia during the entire season. Infected overwintered flowers produced 3-10% as many conidia as newly infected flowers in May and early June. The maximum production of conidia from single overwintered mummified fruits was more than 10 times the conidial production from an overwintered fruit spur or newly infected flower at their respective times of peak sporulation
Sammendrag
Field dissipation of isoproturon in a silty clay loam showed that this herbicides did not leach much below 20 cm i.e. a rapid dissipation in this layer preventedany long-term transport to deeper layers. A degradation product monodesmethyl-isoproturon seemed to be mord readily transported below the plough layer, but only at aminor concentrations.
Sammendrag
Isoproturon is fairly soluble in water and is concidered a risk compound for leaching to surface and ground water. Transformation rates of isoproturon in a silty clay loam from Norway has been studied in the laboratory aswell as in the field.
Sammendrag
Tørråtesoppen førte til stort kjemikalieforbruk grunnet mye primærsmitte og gunstige værforhold for soppen i 2000. "Ny" tørråtesopp kan også være medvirkende til økt bekjempelsesbehov. Omleggingen av tørråtevarslene fra TELEVIS til Internett har gått tilfredsstillende. Generelt har sprøyting etter varsel fungert godt i 2000, selv om det, som i tidligere år, i enkelte felt er en tendens til noe mer angrep på riset enn der det er sprøytet mer rutinemessig. Tørråtesopp-populasjonen i Norge er svært variabel. Begge krysningtyper er vanlig i Sør-Norge, og er påvist i mange felt gjennom hele sesongen. Krysningstype A2 er nå også funnet i Trøndelag. Oosporer dannes i potetriset og kan overleve minst to vintre under våre forhold. Lav sensitivitet overfor propamokarb er påvist hos enkelte isolat av tørråtesopp i Norge og Finland, men svikt i effekt av Tattoo under feltforhold er ikke rapportert. Reglone har effekt mot tørråtesoppen og innblanding av soppmiddel ved risdreping er derfor unødvendig.
Sammendrag
Artikkelen orienterer om resultater fra det brukerstyrte FoU-prosjektet "Fysiologiske skader og algesoppråte i kinakål". Algesopp-problemet i kinakål på åkeren og på lager i Lier skyldes to ulike algesopp-slekter. På åkeren er det Phytium som er hovedproblemet, og da særlig P. tracheiphilum. Under lagring er Phytophthora porri hovedårsak til algesoppråten. Ut fra forsøkene med metalaksyl og ulike dekkmaterialer ser infeksjoner av P. tracheiphilum ut til å skje relativt raskt etter planting. Forsøk i veksthus for å påvise ulik resistens mot P. tracheiphilum gav variable resultater, og det har vært vanskelig å skille sortenes resistens. Feltforsøk på areal med naturlig smitte ser ut til å være sikrest metode til å påvise sortforskjeller
Sammendrag
Four methods were evaluated in measuring resistance of strawberry cultivars to crown rot caused by Phytophthora cactorum. Meristem propagated plants grown in vitro were inoculated with mycelial discs. Four to five days after inoculation, it was possible to distinguish between cultivars with large differences in susceptibility to the disease. Ten days later, all plants were totally necrotic making it impossible to distinguish between cultivars. When detached leaves were inoculated by inoculating a plug of mycelium into the petiole, disease symptoms developed more slowly in resistant cultivars, but leaf age greatly affected the rate of symptom development. When plug plants (not cold stored) were lightly wounded in the rhizome with a scalpel and inoculated with either zoospores or mycelium, differences in disease development between cultivars were mainly as would be expected from previous information on susceptibility, but both age and size of plants influenced the rate of disease development. Unwounded, inoculated plants did not develop symptoms. When cold-stored plug plants were either unwounded or lightly wounded with a scalpel in the rhizome and inoculated with zoospores, the relative rates of disease development consistently reflected the susceptibility to crown rot. At the time of final assessment, disease was much more severe in wounded plants, but the relative susceptibility of cultivars was not affected by the wounding.
Sammendrag
Skildring av prosjektet: Tiltak mot bitterrote i søtkirsebær. Planlagt aktivitet.