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
Aerial dispersal of inoculum is critical to the spread of many plant diseases; including potato late blight (Phytophthora infestans (Pi)), lettuce downy mildew (Bremia lactucae (Bl)) and cucurbit downy mildew (Pseudoperonospora cubensis (Pc)). In addition to relative humidity and temperature, spore survival during aerial dispersal is affected by solar irradiation (SI), in particular during long-distance transport at higher altitudes. We evaluated the potential survival of spores in air by placing detached spores of Pi, Bl and Pc on filter paper in either direct sun or shade at time intervals from 0.5 to 3 h (Pi and Bl), or up to 42 hours (Pc). Thereafter, the filter papers were placed in moist chambers for 15 min prior to incubation on pea agar (Pi) or water agar (Bl and Pc) for 24 h, before the viable spores were enumerated. Spores were considered viable if they exhibited a germ tube or released zoospores. Preliminary results show that no spores of Pi, Bl and Pc germinated after 1, 3 and 30 h exposure to direct sun, with critical SI doses near 700, 2000 and 8500 Wm-2, respectively. In shade, no Pi spores germinated after 3 h, while spores of Bl and Pc were still viable after 3 and 42 h, respectively. In Norway, the potential for long distance distribution of Pi is restricted, but more likely for Bl and Pc. Further experiments will be conducted to find the maximum survival time for spores of these pathogens under Norwegian climatic conditions.
Sammendrag
Aerial dispersal of inoculum is critical to the spread of many plant diseases; including potato late blight (Phytophthora infestans (Pi)), lettuce downy mildew (Bremia lactucae (Bl)) and cucurbit downy mildew (Pseudoperonospora cubensis (Pc)). In addition to relative humidity and temperature, spore survival during aerial dispersal is affected by solar irradiation (SI), in particular during long-distance transport at higher altitudes. We evaluated the potential survival of spores in air by placing detached spores of Pi, Bl and Pc on filter paper in either direct sun or shade at time intervals from 0.5 to 3 h (Pi and Bl), or up to 42 hours (Pc). Thereafter, the filter papers were placed in moist chambers for 15 min prior to incubation on pea agar (Pi) or water agar (Bl and Pc) for 24 h, before the viable spores were enumerated. Spores were considered viable if they exhibited a germ tube or released zoospores. Preliminary results show that no spores of Pi, Bl and Pc germinated after 1, 3 and 30 h exposure to direct sun, with critical SI doses near 700, 2000 and 8500 Wm-2, respectively. In shade, no Pi spores germinated after 3 h, while spores of Bl and Pc were still viable after 3 and 42 h, respectively. In Norway, the potential for long distance distribution of Pi is restricted, but more likely for Bl and Pc. Further experiments will be conducted to find the maximum survival time for spores of these pathogens under Norwegian climatic conditions.
Forfattere
Bjørn Molteberg Trygve S. Aamlid Frank Enger Anne A. Steensohn Åge SusortSammendrag
From 2003 to 2006, three varieties of velvet bentgrass (Agrostis canina), thirteen varieties of creeping bentgrass, nine varieties of colonial bentgrass (Agrostis capillaris), four varieties of slender creeping red fescue Festuca rubra var. trichophylla): thirteen varieties of chewings fescue (Festuca rubra var. commutata), and one variety of annual bluegrass (Poa annua var. reptans) were evaluated for establishment rate, overall turf quality (visual merit), tiller density, color, leaf fineness, per cent living plant cover, winter injury, disease resistance, spring green-up, daily height growth, and thatch accumulation in trials on USGA-spec. putting greens at the Bioforsk research stations Landvik (58°N, 12 m a.s.l.) and Apelsvoll (61°N, 250 m a.s.l.) in south-east Norway. These experimental sites are considered representative for the southern/coastal and the northern/ continental zone of Scandinavia, respectively. The trials were mowed three times per week to 3 mm for bentgrass species and annual bluegrass and to 4-5-5.0 mm for red fescues; fertilized with easily soluble, small-grain mineral fertilizer every second week, and otherwise managed as putting greens with respect to irrigation, vertical mowing, aeration and topdressing. The greens were not open to regular play, but articifial wear was imposed by rolling friction-drums with golf-spikes over the trials three timers per week. On average for varieties within each species, velvet bentgrass had the highest visual merit scores at both experimental sites. Velvet bentgrass had higher density and finer leaves than any other species in the study. Along with colonial bentgrass, it also had better winter survival than creeping bentgrass, red fescue and annual bluegrass. The main disadvantage of velvet bentgrass is its rapid formation of thatch; this problem must be resolved before a general recommendation for use of velvet bentgrass on Scandinavian putting greens can be given. Next to velvet bentgrass, colonial bentgrass and creeping bentgrass were ranked as the most suitable species for golf courses in the northern/continental and southern/coastal zone, respectively. Red fescues should be preferred on golf courses not using fungicides and with limited maintenance budgets. While annual bluegrass `True Putt" cannot be recommended for putting greens in any part of Scandinavia, the ranking of varieties within each species depended, for the most part, on climatic zone. Based on overall performance in this project, a list of recommended varieties are presented for the Scandinavian putting greens.
Forfattere
Stein Rune Karlsen Anne Tolvanen Eero Kubin Jarmo Poikolainen Kjell Arild Høgda Bernt Johansen Fiona S. Danks Paul Eric Aspholm Frans Emil Wielgolaski Olga MakarovaSammendrag
Northern Fennoscandia is an ecologically heterogeneous region in the arctic/alpine-boreal transition area. Phenology data on birch from 13 stations and 16-day MODIS-NDVI composite satellite data with 250 m resolution for the period 2000 to 2006 were used to map the growing season. A new combined pixel-specific NDVI threshold and decision rule-based mapping method was developed to determine the onset and end of the growing season. A moderately high correlation was found between NDVI data and birch phenology data. The earliest onset of the growing season is found in the narrow strip of lowland between the mountains and the sea along the coast of northern Norway. The onset follows a clear gradient from lowland to mountain corresponding to the decreasing temperature gradient. In autumn, the yellowing of the vegetation shows a more heterogeneous pattern. The length of the growing season is between 100 and 130 days in 55% of the study area.
Forfattere
Trygve S. AamlidSammendrag
Med over 40.000 alpinnedfarter tilsvarende et areal på 1.100.000 daa er det i Alpene stort behov for stedegent frø til erosjonssikring og revegetering. På 1980-tallet ble det i regi av Federal Agricultural Research and Eduaction Centre (HBFLA), Raumberg- Gumpenstein, Østerrike innsamlet frø av 300-350 stedegne økotyper fordelt på 40-50 arter på ulike steder i Alpene. Etter et forsiktig utvalg for frøavlsegenskaper ble de mest lovende økotypene av hver art kryssa sammen for å skape genetiske breie "Alpe-sorter" til videre oppformering. I dag er produksjonen av stedegent frø basert på 25 slike populasjoner, en for hver art. Fra midt på 1990-tallet har frøavlen av disse populasjonene frø utviklet seg slik at den i dag legger beslag på ca 1200 daa og er en viktig del av inntektsgrunnlaget for 10-12 bønder. Omfanget av avlen forventes å dobles de nærmeste åra. Frøavlen foregår på kontrakt med det private frøfirmaet "Kärtner Saatbau", men HBFLA er fortsatt engasjert gjennom forskning, rådgivning, markedsføring, og produksjon og leveranse av basisfrø. Frøprisen fastsettes ut fra prinsippet at frøavl av stedegene arter skal gi 50% større dekningsbidrag enn dyrking av høsthvete, og 25% større dekningsbidrag enn ordinær engfrøavl. Etter hvert som frøavlerne har vunnet erfaring, har det vært en kraftig økning i avlingsnivået, og dermed er frøprisene redusert. I utsalg er de stedegene frøblandingene om lag 2.5 ganger dyrere enn konkurrerende, tradisjonelle (hovedsakelig importerte) blandinger. Frøavlen av stedegne arter er ikke underlagt offentlig kontroll, men det er selvpålagte krav til renhet og spireevne som er på høyde med eller litt lavere enn ved tradisjonell engfrøavl. På nasjonalt nivå har Østerrike ingen lover eller forordninger som pålegger eiere av alpinanlegg eller andre utbyggere å bruke stedegent frø, men stadig flere velger likevel å bruke dette fordi arealer tilsådd med stedegne blandinger er mer varige og setter mindre krav til gjødsling, slått og resåing enn arealer tilsådd med tradisjonelle blandninger.
Forfattere
Gunnhild Wærsted Takle Ian Toth May Bente BrurbergSammendrag
During the last years, Norway and several other countries have seen an increase in potato blackleg disease caused by the Gram-negative bacterium Pectobacterium atrosepticum (formerly known as Erwinia carotovora ssp. atroseptica). P. atrosepticum has a narrow host range, limited almost exclusively to potato plants in temperate regions, where it also causes soft rot of potato tubers. The pathogen spreads from infected seed tubers to progeny tubers either through the plant or over short distances in the soil. However, little is known about how seed potatoes are initially contaminated with the bacterium and what onsets the infection. Our overall aim is to understand the underlying molecular mechanisms behind potato infection by P. atrosepticum and to find possible means of controlling blackleg disease, as well as providing more knowledge of the overall lifestyle of the bacterium. The sequencing and annotation of the genome of P. atrosepticum strain SCRI1043 (Bell et al., 2004. Proc.Natl.Acad.Sci. 101: 11105-10) as well as a genome-wide mutant library (Holeva et al., 2004. Mol. Plant. Microbe. Interact. 17:943-50) provide valuable tools in examining the molecular aspects of both pathogenesis and environment related factors. Quorum-sensing seems to play an essential role in the pathogenesis of P. athrosepticum, and we are currently studying some of the many genes affected by this regulatory control as well as other putative virulence genes.
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.
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.
Forfattere
Håvard SteinshamnSammendrag
Grassland legumes are essential in organic ruminant livestock production due to their ability to fix atmospheric nitrogen (N), providing high yields of high feeding value without N fertilization. White clover (Trifolium repens L.) and red clover (Trifolium pratense L.) are the most important legumes of temperate grasslands with white clover as the most widely used. New research has reviled new properties of red clover that may affect animal performance and product quality significantly. Red clover containing diets have increased the production of milk and meat (compared with grasses) and the content of beneficial fatty acids in milk and meat (compared with grasses and other legumes), improved the efficiency of feed N utilization (compared with Medicago sativa L.), and increased the milk content of isoflavones (compared with grass and white clover). Red clover contains high levels of the enzyme polyphenol oxidase that might reduce the extent of lipolysis and proteolysis. The paper presents a review on resent results from own and others" research on the use of red clover in the diet of ruminants and the likely mechanisms by which red clover affects production and product quality
Forfattere
Thomas Hartnik Line Sverdrup John JensenSammendrag
lpha-cypermethrin, a synthetic pyrethroid, is used as an insecticide in agricultural settings, and increasingly replaces organophosphates and carbamates due to lower application rates and lower mammal toxicity. As very little is known about the acute and chronic toxicity for soil living organisms, this study investigated acute and sublethal toxicity of alpha-cypermethrin for four terrestrial invertebrate species in an agricultural soil from Norway. Bioassays with the earthworm Eisenia fetida, the potworm Enchytraeus crypticus, the springtail Folsomia candida and the land snail Helix aspersa were performed according to slightly modified versions of OECD- or ISO-guidelines and resulted in median lethal concentrations (LC50) of >1000 to 31.4 mg/kg and sublethal no-effect-concentrations (NOEC) of 2.51 to 82 mg/kg. A high acute-to-chronic ratio (ACR) was found in especially the earthworms. Interspecies differences in sensitivity may be explained by differences in exposure and differences in metabolisation rate. When based on measured pore water concentrations, terrestrial species appear overall to be about one order of magnitude less sensitive than aquatic species. Effect assessments conducted according to European guideline for risk assessment of pesticides reveal that assessments based on acute toxicity tests are not always conservative enough to warrant environmentally safe concentrations in soil. Mandatory incorporation of sublethal toxicity data will ensure that also in regions with temperate climate effects of pesticides on populations of soil living organisms are unlikely.