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.
2006
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Våren 2002 oppdaget flere skogeiere at en del av granplantene som ble plantet ut høsten før hadde toppavdøing. Samtidig registrerte planteskolebestyrere at noen av granplantene som skulle plantes ut hadde visnesymptomer. Ved Skogforsk ble disse plantene undersøkt ved hjelp av tradisjonelle og moderne molekylære teknikker.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Magnus Karlsson Ari M. Hietala Harald Kvaalen Halvor Solheim Åke Olson Jan Stenlid Carl Gunnar FossdalSammendrag
Norway spruce (Picea abies (L.) Karst.) has a natural distribution in the northern parts of Europe and Asia and is economically the most important tree species grown in the Nordic countries. A common threat to Norway spruce is the basidiomyceteous fungus Heterobasidion parviporum Niemelä and Korhonen. H. parviporum mainly attacks Norway spruce, although Siberian fir (Abies sibirica Ledeb.) and Scots pine (Pinus sylvestris L.) occasionally get infected. One obstacle to studying host/pathogen interaction in conifers has been the limited availability of mature clones for controlled inoculations, as genetic variation within the host material and the lack of replicates complicate interpretation of the results. Somatic embryogenesis, rooted cuttings, and tissue cultures may provide solutions for this problem. Tissue cultures from mature Norway spruce trees have been proposed as a possible model system for assessing resistance toward fungal pathogens. Recent data on chitinase isoform activity in the Norway spruce/H. parviporum pathosystem are encouraging; clonal variation was observed in the isoforms affected by inoculation, and the isoforms showing increased band intensity following bark inoculation by H. parviporum were also induced in the inoculated tissue cultures of the corresponding clones. To investigate the biological relevance of tissue cultures in host-pathogen interaction studies, transcript levels of selected host and pathogen genes in tissue cultures of Norway spruce were compared to those in bark of 33-year-old ramets of the same clones upon challenge by the pathogenic fungus H. parviporum. Similar transcript profiles of the pathogen and host genes were observed in both tissues, this supporting the use of tissue cultures as experimental material for the pathosystem. Higher transcript levels of the host genes phenylalanine ammonia lyase, peroxidase, and glutathione-S-transferase were observed in the more resistant clone #589 than in the less resistant clone #409 during the early stages of colonization. The most striking difference between the spruce clones was related to gene transcript levels of a class IV chitinase, which showed a continuous increase in clone #409 over the experimental period, with a possible association of this gene product to programmed cell death. Several of the fungal genes assayed were differentially expressed during colonization, including putative glutathione-S-transferases, laccase, cellulase, cytochrome P450 and superoxide dismutase genes. The transcriptional responses suggest an important role for the antioxidant systems of both organisms.
Sammendrag
In spring 2002, extensive damage was recorded in southeast Norway on nursery-grown Norway spruce seedlings that had either wintered in nursery cold storage or had been planted out in autumn 2001. The damage was characterised by a top shoot dieback. Two visually distinct types of necroses were located either on the upper or lower part of the 2001-year-shoot. Isolations from the upper stem necroses rendered Gremmeniella abietina, while Phomopsis sp. was isolated mostly from the lower stem necroses. RAMS (random amplified microsatellites) profiling indicated that the G. abietina strains associated with diseased nursery seedlings belonged to LTT (large-tree type) ecotype,and inoculation tests confirmed their pathogenicity on Norway spruce seedlings. Phomopsis sp. was not pathogenic in inoculation tests, this implying it may be a secondary colonizer. We describe here the Gremmeniella – associated shoot dieback symptoms on Norway spruce seedlings and conclude that the unusual disease outburst was related to the Gremmeniella epidemic caused by the LTT ecotype on large Scots pines in 2001. The role of Phomopsis sp. in the tissue of diseased Norway spruce seedlings is yet unclear.
Sammendrag
We describe the cloning and characterization of a single copy gene from Trichoderma atroviride P1 encoding a novel 30 kDa chitinase, Ech30. Ech30 is a family 18 chitinase showing low sequence similarity to other Trichoderma chitinases. Real-time quantitative RT-PCR studies revealed that expression of the ech30 gene was induced by the presence of Botrytis cinerea in plate confrontation assays, but hardly by chitin in liquid cultures. Studies of Ech30 purified from an Escherichia coli strain overexpressing the ech30 gene devoid of the leader sequence and a predicted intron, showed that the gene encodes an active chitinase, which, as expected for family 18 chitinases, is inhibited by allosamidin.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
2005
Sammendrag
A mixed model approach was used to estimate variance components and heritabilities for resistance to powdery mildew, a wind-borne disease in strawberry. In order to improve precision in the statistical computations, spatial error control effects were included to account for systematic environmental variations in the large field trials. Pedigree information was included where feasible. Seedling families obtained from an incomplete 63-by-63 diallel cross were grown at six locations and scored subjectively for mildew attack three times during the growing season. The 63 parents included both European and American cultivars as well as advanced selections from various breeding programmes. A total of 298 full-sib families were realized, including 26 reciprocal families. No reciprocal differences were found. On a plot-mean basis, the broad-sense heritability was found to be intermediate, H2=0.44"0.50, depending on whether the pedigree information was included in the model or not. The increase was mainly due to a substantial increase in the additive variance component. Likewise, the narrow-sense heritability increased from h2=0.39 to h2=0.45 when the pedigree information was included, while the ratio of the specific combining ability variance to the general combining ability variance fell from 13% to 10%. The predicted breeding values of the 63 parents demonstrate that important cultivars such as Elsanta and Korona are unlikely to produce progenies with a high degree of resistance. On the other hand, the Norwegian cultivar Solprins, the Canadian cultivar Kent and the Italian cultivar Patty appeared to give highly resistant progeny. At the full-sib level, the estimated disease scores ranged from 1.15 (Kent × Induka) to 4.19 (Cavendish × Avanta), revealing a huge range of variation for powdery mildew resistance available for selection.
Forfattere
Jahn DavikSammendrag
Resultat frå jordbærforedling i Planteforsk vert presentert. Fire sortar frå prosjektet er gitt namn. Dei mest lovande av desse ser ut til å vere `Babette" og `Hanibal". `Babette" konkurrerer godt med `Honeoye" i tidlegsegmentet. `Babette" har litt høgare avling enn `Honeoye", større bær og skårer betre på kvalitetseigenskaper ved bæret og den er også sterkare mot mjøldogg på planta. `Hanibal" har omlag samme avlingsprofil som `Korona" og `Polka" og skil seg frå desse med betre bærkvalitet. Spesielt skalstyrke, fastheit og heilskapen er betre, samstundes som den skårer minst like bra på smak. Tre nye seleksjonar vert omtala. PK98.12 er aktuell for hovedsesongen medan PK98.204 er aktuell for tidlegsesongen. PK98.204 produserer vesentleg betre enn `Honeoye" samstundes som den har betre bærkvalitet og smak. PK98.12 skil seg frå `Korona" spesielt på bærstorleik og ytre kvalitetseigenskaper. PK97.48.1 har etter utprøving hos prøvedyrkarar kome i fokus som ein mogeleg industrisort. I våre eigne forsøk har PK97.48.1 vore produktiv, men noko småfallen samenlikna med til dømes `Korona". Til konsumbær har den difor falle igjennom. Seleksjonen har imidlertid svært gode konserveseigenskaper.