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
Det er ikke registrert sammendrag
Forfattere
A. Lehtinen A. Hannukkala B. Andersson Arne Hermansen Vinh Hong Le Ragnhild Nærstad May Bente Brurberg B.J. Nielsen J. G. Hansen J. YuenSammendrag
Det er ikke registrert sammendrag
Forfattere
Ari Lehtinen Asko Hannukkala Björn Andersson Arne Hermansen Vinh Hong Le Ragnhild Nærstad May Bente Brurberg Bent J Nielsen Jens G Hansen Jonathan YuenSammendrag
A total of 743 single-lesion isolates of Phytophthora infestans were collected in summer 2003 from Denmark, Finland, Norway and Sweden. Most of the isolates were tested for mating type, snd subsets for sensitivity to fungicides and virulence (host specific pathogenicity). Approximately 60 % of the isolates were A1 mating type in each country. Both mating types were present in 40 % of the fields where more than one isolate was tested,indicating strong potential for sexual reproduction. The proportion of metalaxyl-resistant isolates dropped under 15 % from the 60% observed in the early 1990s in Norway and Finland, possibly due to lower selection pressure because of decreased use of metalaxyl. PropamocarbHCl sensitivity remained unchanged in the Nordic countries compared to the situation in 1997-2000 in Finland. Four isolates collected from Finland and Sweden were able to sporulate in the presence of this fungicide at a concentration of 1000 mg L-1. In Norway and Finland the frequencies of virulence factors and pathotypes remained nearly unchanged since 1990s, but the mean number of virulence factors per isolate increased from 5.6 to 6.3. In Denmark and Sweden virulence factors 2 and especially 6 were more common than in Norway and Finland. In addition, in the Swedish population the frequencies of pathotypes were quite even while in other countries pathotype 1.3.4.7.10.11 was most prevalent.
Forfattere
V. Leth Jan Netland C. AndreasenSammendrag
Det er ikke registrert sammendrag
Forfattere
Anne Bøen Arne GrønlundSammendrag
Total waste P flows are of such magnitude that they potentially could serve as a P resource in food production. However, neither waste treatment nor applications of WBPs are optimized for high recycling efficiency today. There is a need for methods to evaluate and communicate about nutrient recycling from waste and substitution rate is one interesting option.
Forfattere
Anne Bøen Arne GrønlundSammendrag
Total waste P flows are of such magnitude that they potentially could serve as a P resource in food production. However, neither waste treatment nor applications of WBPs are optimized for high recycling efficiency today. There is a need for methods to evaluate and communicate about nutrient recycling from waste and substitution rate is one interesting option.
Forfattere
Mari Mette TollefsrudSammendrag
Norway spruce (Picea abies), a conifer of the boreal forest, is one of the ecologically and economically most important forest tree species in Europe. It is naturally distributed into two disjunct ranges, one northern and one southern. In this thesis, genetic variation in Norway spruce populations has been investigated to obtain a comprehensive understanding of how its genetic structure has been shaped by Quaternary climate changes, hybridization with Siberian spruce (P. obovata), present-day ecological marginality and adaptive changes. Recently compiled fossil records of Norway spruce have moreover been used for inference of glacial refugia and the direction of migration routes. In Paper I, we combine fossil pollen data with a dataset of the maternally inherited, seed-dispersed mitochondrial (mt) marker nad1 obtained from 369 populations (4876 trees) to infer glacial refugia, postglacial colonization routes and the genetic consequences of range contractions and expansions. The combined data suggest that Norway spruce survived in at least seven refugial areas from which it expanded in the Holocene. These were the Russian plains, south-eastern Alps, southern Bohemian Massif including its southern foreland, northern Dinaric Alps, northern Carpathians, southern Carpathians and south-west Bulgarian mountains. Siberian spruce survived the last glacial maximum east of the Ural Mountains, separated from the refugia of Norway spruce (Paper III). Genetic diversity in Norway spruce showed an overall decrease from the oldest regions towards the younger regions. The different refugia had, however, contrasting genetic structuring and there were large differences in the genetic patterns along the different colonization routes. In the Alps, for example, diversity decreased over very short distances, whereas diversity in northern Europe was maintained over large distances. In Paper II we obtained a deeper insight into the genetic structuring of the northern European populations by analyzing nuclear microsatellite variation. Very little differentiation was revealed across the northern European range, manifesting high levels of past and present gene flow. Despite little differentiation, the microsatellite structure corroborated the mtDNA-based hypothesis of expansion out of one large Russian refugium along two separate migration routes, one northwestern route through Finland into northern Scandinavia and one southwestern route across the Baltic Sea to southern Scandinavia. In the south, microsatellite diversity was largely maintained from east to west, suggesting that pollen flow has efficiently counteracted the loss of diversity following colonization. Towards the northern climatic margin, nuclear microsatellite diversity decreased and inbreeding increased, probably due to smaller effective population size and more limited pollen production in the north, promoting mating among relatives. In Paper III, we investigated genetic differentiation between Norway spruce and Siberian spruce with mtDNA and chloroplast (cp) DNA markers. Chloroplast DNA is paternally inherited and spread with both seeds and pollen. We found two main genetic groups with both types of markers, corresponding to the two species and associated with separate refugia west (Norway spruce) and east (Siberian spruce) of the Ural Mountains. The Ural Mountains do not constitute a major barrier to gene flow. mtDNA haplotypes of Norway spruce were found east of the Ural Mountains, and extensive paternal introgression from Siberian spruce to Norway spruce was suggested across the Ural Mountains. Extensive pollen flow is in agreement with the homogenization observed in both the chloroplast (Paper III) and the nuclear (Paper II) gene pool of northern European Norway spruce. Pollen flow mainly occurs from Siberian spruce to Norway spruce, and Siberian spruce thus disperses westwards through paternal introgression. With the mtDNA marker nad1, it is possible to trace the origin of central European and northern European trees with a simple assay. In Paper IV, we determined the origin of trees in Norway spruce plantations. This was done prior to a greenhouse experiment recording the timing of terminal bud set of seedlings of different origins. We found that seedlings of central European origin from seeds produced in Norway had on average a bud set more similar to local Norwegian seedlings than to central European seedlings from seeds produced in central Europe. This suggests that the progenies of trees of central European provenances growing in Norway may have a rapid adaptation to the northern climate. Norway spruce thus not only has a fast and extensive migratory capacity but also a fast adaptative capacity, which may facilitate its altitudinal migration as climate warming proceeds.
Forfattere
Knut Anders Hovstad Mikael OhlsonSammendrag
A field experiment was conducted in a semi-natural grassland to study the interspecific variation in the effect of litter on seedling emergence and establishment and separate physical from chemical effects. Seeds of seven forb species were sown in plots subjected to either litter amendment (0, 400 or 900 g m–2) or water extracts of litter (corresponding to 400 and 900 g litter m–2). In addition, an extract was treated with activated carbon to estimate the possible effects of secondary chemical compounds.The response to plant litter differed amongst species: negative, neutral and positive responses were observed. Anthriscus sylvestris was the only species with a strong positive response to litter. We found no consistent relation between seed size and response to plant litter. Physical effects of litter were generally stronger than chemical effects. However, water extract of litter inhibited emergence in three species. Activated carbon removed the negative effect of the litter extract, which suggests that the effect was caused by an inhibitory chemical compound rather than by increased competition in response to nutrients added via the extract. The balance between facilitative and inhibitory effects of litter depended on species identity and litter quantity. Facilitative effects dominated at low and intermediate quantities of litter, and inhibitory effects at high litter quantities. One species, Campanula rotundifolia, showed a switch from positive to negative responses with increasing quantities of litter. However, we found no general threshold for litter quantity valid across species.
Sammendrag
Vi studerer to sykdommer forårsaket av Phytophthora, rotstokkråte i jordbær (P. cactorum) og rød rotråte i bringebær (P. fragariae var. rubi (Pfr)). Bringebær og jordbær sorter varierer i resistens, men de fleste kommersielle kultivarene er mottakelige for disse to sykdommene. En universell merkemetode ble brukt for å gjøre markøranalyse for å identifisere genetiske markører koblet til resistens. For bringebær er populasjonen brukt for kartlegging avkommene fra en krysning mellom resistent Asker og mottakelig Glen Moy. Resistensen til 200 avkom har blitt testet under kontrollerte betingelser med smitting i vannkultur. Tretti dager etter inokulering med mycel av Pfr ble grad av symptom registrert. Kommersielt dyrket jordbær er en svært heterozygot oktoploid. Vi bruker derfor diploid villjordbær som en modellplante. Bioforsk har en samling av diploide jordbærgenotyper fra ulike steder i Norge. Totalt har 68 genotyper blitt testet for deres resistens mot P. cactorum. Ulik grad av resistens har blitt observert. Mottakelige så vel som svært resistente aksesjoner har blitt identifisert. Basert på disse resultatene vil genotyper bli valgt for å lage en segregerende populasjon fra en resistent x mottagelig krysning for å studere nedarvingen av P. cactorum resistensen.
Sammendrag
Vi studerer to sykdommer forårsaket av Phytophthora, rotstokkråte i jordbær (P. cactorum) og rød rotråte i bringebær (P. fragariae var. rubi (Pfr)). Bringebær og jordbær sorter varierer i resistens, men de fleste kommersielle kultivarene er mottakelige for disse to sykdommene. En universell merkemetode ble brukt for å gjøre markøranalyse for å identifisere genetiske markører koblet til resistens. For bringebær er populasjonen brukt for kartlegging avkommene fra en krysning mellom resistent Asker og mottakelig Glen Moy. Resistensen til 200 avkom har blitt testet under kontrollerte betingelser med smitting i vannkultur. Tretti dager etter inokulering med mycel av Pfr ble grad av symptom registrert. Kommersielt dyrket jordbær er en svært heterozygot oktoploid. Vi bruker derfor diploid villjordbær som en modellplante. Bioforsk har en samling av diploide jordbærgenotyper fra ulike steder i Norge. Totalt har 68 genotyper blitt testet for deres resistens mot P. cactorum. Ulik grad av resistens har blitt observert. Mottakelige så vel som svært resistente aksesjoner har blitt identifisert. Basert på disse resultatene vil genotyper bli valgt for å lage en segregerende populasjon fra en resistent x mottagelig krysning for å studere nedarvingen av P. cactorum resistensen.