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
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.
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
Matias Pasquali Erik Lysøe Kye-yong Seong Sonja Klemsdal J.R. Xu Li-Jun Ma H. Corby KistlerSammendrag
To understand trichothecene accumulation and the infection cycle of the head light pathogen Fusarium gramineaum sesu stricto, fungal gene expression profiles were monitored during plant infection using the F. graminearum Affymetrix GeneChip. Strains containing mutations in genes for three transcription factors were found to control trichothecene accumulations in planta and pathogenicity. Expression profiles were compared between wildtype and these mutants during infection of wheat. Mutants deleted for the StuA gene were greatly decreased in sporulation and produced no perithecia in culture. Unlike stuA mutants in F. oxysporum, F. graminearum stuA mutants were greatly reduced in pathogenicity. Reducd pathogenicity may be due to decreased trichothecene levels in planta, which in the mutant were two-fold in either tri6 or tri10 deleted strains. A model for global regulation and cross pathway control of sporulation, mycotoxin biosynthesis and pathogenicity will be presented.
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.
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.
Forfattere
Kerry O\"Donnell Todd J. Ward Dereje Aberra T. Aoki H. Corby Kistler Åsmund Bjørnstad Sonja Sletner KlemsdalSammendrag
Tyve isolater som lignet isolater i Fusarium graminearum (Fg) artskomplekset ble isolert fra hvete fra to forskjellige geografiske områder i Etiopia. Multilokus DNA sekvensdata (13 gener: 16.3 kb/ isolat) viste at de etiopiske isolatene tilhørte en ny monophyletisk søstergruppe til F.acaciae-mearnsii innen Fg komplekset. Analyse med MLGT prober viser at det i disse isolatene har skjedd en rekombinasjon mellom isolater med en 15ADON og NIV kjemotype, og dette ble bekreftet med DNA sekvensering. Dette er første gang en slik rekombinasjon innen TRI klusteret er vist. Patogenitetstester viser at denne nye arten kan gi Fusarium Head Blight i hvete og danne 15ADON in planta.
Forfattere
Kerry O\"Donnell Todd J. Ward Dereje Aberra T. Aoki H. Corby Kistler Åsmund Bjørnstad Sonja KlemsdalSammendrag
Tyve isolater som lignet isolater i Fusarium graminearum (Fg) artskomplekset ble isolert fra hvete fra to forskjellige geografiske områder i Etiopia. Multilokus DNA sekvensdata (13 gener: 16.3 kb/ isolat) viste at de etiopiske isolatene tilhørte en ny monophyletisk søstergruppe til F.acaciae-mearnsii innen Fg komplekset. Analyse med MLGT prober viser at det i disse isolatene har skjedd en rekombinasjon mellom isolater med en 15ADON og NIV kjemotype og dette ble bekreftet med DNA sekvensering. Dette er første gang en slik rekombinasjon innen TRI klusteret er vist. Patogenitetstester viser at denne nye arten kan gi Fusarium Head Blight i hvete og danne 15ADON in planta.
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.