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
Planteparasittære nematoder er små rundormer som skader røttene på korn. Symptomene viser seg som tynn plantebestand, svake planter og mer ugras. I de siste årene viser henvendelser fra produsenter at problemene med nematoder er økende. Prøver med korncystenematoder, rotsårnematoder og stuntnematoder er vanlig. I prøvene hvor resistente sorter for korncystenematoder er dyrket, og skader vises, er ofte rotsårnematoder funnet. Rotsårnematoder er påvist i forbindelse med skader i alle kornarter. I en del av feltene som er undersøkt i Vestfold, Østfold, Agder, Romerike og Buskerud er det vist til dels høge populasjoner av rotsårnematoder.
Forfattere
Ricardo Holgado Anette Stryken Christer Magnusson Irene Rasmussen Kari-Ann Strandenæs Bonsak HammeraasSammendrag
Bioforsk gjennomførte i samarbeid med Lier og omegn forsøksring en kartlegging av planteparasittære nematoder i Lier. Dette p.g.a. at det i 2006 ble påvist skader av nematoder i stilkselleri hos en dyrker i Lier. I vekstsesongen 2007 ble det gjort undersøkelser i 37 prøver fra grønnsakfelt fra 7 produsenter, hvor det ble dyrket blomkål, brokkoli, kinakål, isberg salat, stangselleri, og fra felter som var brakk/pløyd/frest. Det ble funnet stuntnematoder (Tylenchorhynchus sp.)i 27 prøver (72,9 %), Kålcystenematoder (Heterodera cruciferae) og cystenematoder (Heterodera spp.) i 25 prøver (67,5 %), rotsårnematoder (Pratylenchus spp.) i 20 prøver (54 %), pin-nematoder (Paratylenchus spp.)i 11 prøver (29,7 %), og spiralnematoder i 3 prøver (8,1 %).
Sammendrag
Søtkirsebærtre vart sprøyta med kalsiumoppløysing ei gong kvar veke frå krunbladfall til to veker før hausting. Frukt frå trea som hadde fått kalsiumtilførsel, hadde høgare innhald av oppløyst turrstoff. Det var ikkje signifikante skilnader i farge, fastleik og syreinnhald. Bladgjødsling med kalsium reduserte utviklinga av kutikulære frakturar på fruktene. Fruktene frå kalsiumsprøyta tre mista meir vekt under lagring enn frukter frå kontrolltre. Hjå kontrollfrukter med mange kutikulære frakturar var vekttapet større enn hjå tilsvarande frukter med få frakturar. Hjå frukter som var tilført kalsium som bladgjødsling, derimot, var det ingen skilnad i vekttapet mellom frukter med mange eller få kutikulære frakturar. Dette indikerer at dei kutikulære frakturane i kalsiumsprøyta frukt var mindre alvorlege (djupe). Innhaldet av fenoliske sambindingar var større i kalsiumsprøyta frukt enn i kontrollfrukt. Færre kutikulære frakturar, mindre alvorlege (djupe) frakturar og auka innhald av fenolar kan vera ulike mekanismar for reduksjonen i risikoen for soppsjukdomar som ein observerer i kalsiumsprøyta søtkirsebær.
Forfattere
Guro BrodalSammendrag
Det er ikke registrert sammendrag
Forfattere
Guro BrodalSammendrag
Det er ikke registrert sammendrag
Sammendrag
The last few years, increasing levels of DON (deoxynivalenol) have been recorded in Norwegian cereals, particularly in oats. In the same period, increased occurrence of F. graminearum has been reported in Norway as well as in the Western part of Europe. There may be several reasons for this change: Climate change, altered distribution of cereal cultivars, pathogen adaptation to cooler regions etc. We aim to clarify whether the increasing occurrence of F. graminearum in Norwegian cereals is connected to a change in the distribution of genotypes of this species. Fifty `old" F. graminearum isolates collected from Norwegian grown cereals during the 1990s will be compared to a similar number of `new" isolates collected in recent years (2005-2007). Isolates from Germany, Russia, Finland and the US will be used for comparisons. The genetic diversity of these about 110 isolates (50 `new", 50 `old" and 10 non-Norwegian isolates) will be investigated by AFLP (amplified fragment length polymorphism). These isolates will also be identified phylogenetically and characterised to chemotype. In addition, some selected isolates will be assessed for aggressiveness on wheat and specific characters potentially important for fungal distribution such as in vitro growth rate, spore production and perithecia formation.
Sammendrag
The last few years, increased prevalence of Fusarium graminearum has been reported in Norway as well as in the Western part of Europe. This increased occurrence of F. graminearum in Norway is confirmed by comparing a survey on F. graminearum prevalence during the 1990"s with recent data.
Forfattere
Guro BrodalSammendrag
Fusarium head blight (FHB) or scab, seedling blight and foot rot are widespread and destructive diseases of small grain cereals (wheat, barley, oats, rye and triticale) throughout the world. The main causal agents are Fusarium culmorum, F. graminearum, F. avenaceum, F. poae, F. sporotrichioides and Microdochium nivale. More recently also F. langsethiae, previously described as "powdery F. poae", seems to be widespread at least in Scandinavian countries, especially in oats. In addition to causing yield losses, FHB is of great concern because of the potential of these Fusarium species, except M. nivale, to produce a range of secondary metabolites known as mycotoxins in the grain. Mycotoxins cause a potential health risk when contaminated grain is consumed in human and animal food products. The development of FHB is, to a large extent, determined by climatic conditions. It is generally agreed that plants are most susceptible to FHB at anthesis and moist conditions during the anthesis period are important for infection. In hotter regions, F. graminearum is generally regarded as the most important species. In cooler areas, such as Northwest Europe, F. culmorum, F. poae, F. langsethiae and M. nivale has been of greater importance. However, recent investigations indicate that the incidence of F. graminearum has increased considerably in usually cooler regions, including Scandinavian countries. In Norway, a more aggressive and fast growing F. graminearum type was observed in 2004 in the oat cultivar Bessin. A number of seed lots of this cultivar showed severely reduced germination capacity, which was due to a large proportion of infected seed. Mycotoxin analyses of some of the lots showed very high contents of DON (e.g. 25-30 000 ppb). This "new" F. graminearum is now recorded from several areas and also in barley and wheat seed, however, mostly in low frequencies. Nevertheless some serious mycotoxin occurrences have been reported particularly in oats. Research is being carried out to determine if this strain is really new, and if it is likely that it was introduced into Norway by importing infected seeds. Seed health testing of wheat seed in Norway is routinely carried out on agar plates (PDA) and M. nivale and Fusarium spp. are recorded separately. A survey of infection frequencies in Norwegian spring wheat seeds harvested during the years 2000 " 2007 showed that the proportion of M. nivale has decreased whereas Fusarium spp. has increased. In general, the increased occurrence of FHB is believed to be caused by changed cultivation practice, i.e. cereal growing in monoculture over large areas in combination with conservation tillage, which leaves large amount of inoculum on the ground. Possible reasons for the increased occurrences of F. graminearum in cooler regions are the adaptation of the pathogen to cooler conditions and that cooler regions may have gradually become warmer due to possible climate change. Increased FHB is also connected to increased production of maize. Incidence and severity of FHB are often significantly greater when wheat follows maize than when wheat follows other crops. The species responsible for FHB can also cause seedling blight and foot rot. However, the epidemiological relationship between these three diseases is not clear. There is little evidence that seed infection leads to the production of significant quantities of primary inoculum for head blights. More research in this area is needed to understand the role of seed infection in spread and development of FHB. Will it be possible to reduce FHB and the mycotoxin threat with the use of healthy seed? If yes, how is it possible to produce seed without Fusarium?
Forfattere
Guro BrodalSammendrag
Det er ikke registrert sammendrag
Forfattere
Guro BrodalSammendrag
Det er ikke registrert sammendrag