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
Healthy seed is important for a successful plant production and organic cereal production must rely on management of seed-borne diseases without synthetic seed treatment chemicals. Inoculum thresholds, i.e. the level of seed borne inoculum that can be accepted, are needed for organic cereal production. In general, significantly lower infection frequencies of seed borne diseases are recorded on seedlings than on seed. The aim of the work presented was to compare transmission of Drechslera teres from barley seeds to seedlings in soils with different content of organic materials. Experiments with two seed lots (93 % and 94 % D. teres, respectively) have been carried out in greenhouse with 8 different soils collected in different cereal growing regions. 100 seeds with 3 replicates from each seed lot were planted in each soil type and placed for emergence at 12 oC. Percent emergence and percentage seedlings with symptoms of net blotch were recorded at BBCH 10-12. The net blotch frequency as average for the two seed lots ranged from 11 to 21 % in the different soils. Higher content of organic materials resulted in less infection frequencies. A correlation was found between the amount of organic materials in the soil and % net blotch (r = -0.83, P = 0.009). Experiments will be repeated with less infected seed lots.
Forfattere
Guro BrodalSammendrag
Det er ikke registrert sammendrag
Sammendrag
Increasing levels of Fusarium toxins, particularly deoxynivalenol (DON), T-2 /HT-2 and moniliformin, have been recorded in Norwegian cereals during the last few years. Previously F. avenaceum, F. culmorum, F. poae and F. tricinctum were the most common Fusarium species found on cereals in Norway. However, more recently F. graminearum has occurred more frequently, and the T-2/HT-2 toxin producing species F. langsethiae has also been detected, especially in oats. Investigations were made to clarify if there has been a change in the composition of Fusarium species. We are aiming to establish a three-step screening system in order to identify grain lots with high levels of Fusarium toxins: 1- Identify `high-risk" fields/lots, based on information on cultivation practice and climatic conditions, through the use of a FHB-prediction model. 2- Analyze the `high-risk" lots using a rapid test selected for its capacity to detect Fusarium toxins in a large number of grain samples at low cost. 3- Forward selected samples (based on analyses in step 2) for chemical mycotoxin analyses. Since 2004, we have run chemical mycotoxin analyses on grain samples from oat and spring wheat grown in Norway under different climatic conditions. Prediction models will be developed to estimate the risk of Fusarium infection and mycotoxin development in cereal fields, based on data for weather and cultivation practices. Preliminary results from using the prediction models will be presented.
Forfattere
Sonja Klemsdal Heidi Udnes Aamot Erik Lysøe Jafar Razzaghian Oleif Elen Ingerd Skow Hofgaard Marika Jestoi Guro BrodalSammendrag
I to veksthusforsøk ble hvete og havre sprayinokulert under blomstring med en enkelt eller en blanding av flere Fusarium arter. De artene som ble studert var F. graminearum, F. culmorum, F. avenaceum, F. poae og F. langsethiae. Vi studerte i hvilken grad samspillet mellom artene påvirket etableringen og veksten av Fusarium, og også hvilken effekt dette hadde på mykotoksinproduksjonen.
Sammendrag
Increasing levels of Fusarium toxins, particularly deoxynivalenol (DON), T-2 /HT-2 and moniliformin, have been recorded in Norwegian cereals during the last few years. Previously F. avenaceum, F. culmorum, F. poae and F. tricinctum were the most common Fusarium species found on cereals in Norway. However, more recently F. graminearum has occurred more frequently, and the T-2/HT-2 toxin producing species F. langsethiae has also been detected, especially in oats. Investigations were made to clarify if there has been a change in the composition of Fusarium species. We are aiming to establish a three-step screening system in order to identify grain lots with high levels of Fusarium toxins: 1- Identify `high-risk" fields/lots, based on information on cultivation practice and climatic conditions, through the use of a FHB-prediction model. 2- Analyze the `high-risk" lots using a rapid test selected for its capacity to detect Fusarium toxins in a large number of grain samples at low cost. 3- Forward selected samples (based on analyses in step 2) for chemical mycotoxin analyses. Since 2004, we have run chemical mycotoxin analyses on grain samples from oat and spring wheat grown in Norway under different climatic conditions. Prediction models will be developed to estimate the risk of Fusarium infection and mycotoxin development in cereal fields, based on data for weather and cultivation practices. Preliminary results from using the prediction models will be presented.
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.
Sammendrag
I 2004 Phytophthora capsici ble funnet i veksthusagurk i Norge.
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
Sammendrag
Det er ikke registrert sammendrag