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
Forfattere
Guro BrodalSammendrag
Det er ikke registrert sammendrag
Foredrag – Thresholds for seed borne diseases in organic cereal seed
Guro Brodal, Birgitte Henriksen
Sammendrag
To avoid problems with seed borne diseases in organic cereal production, seed health testing should be compulsory in certification of organic seed. In general, significantly lower infection frequencies of seed borne diseases are recorded on seedlings than on seed. Thresholds for the amount of seed borne inoculum that can be accepted for organic production are therefore needed. The aim of the work presented is to compare transmission rates of Drechslera on barley and oats under organic and conventional conditions, to be able to decide if existing thresholds used to assess the need of chemical seed treatment, can be applied for acceptance of organic seed lots, or for recommendation of alternative treatments. Field experiments were carried out in 2005 in conventional and organic fields situated close to each other at each of three locations (south/east-Norway, east-Norway and mid-Norway). 10 seed lots of barley and 10 lots of oats, with a range of seed infections (barley: 0-94 % Drechslera teres, average 23,7 %; oats: 0-66 % Drechslera avenae, average 22,0 %) were planted in rows of 100 seeds with 8 replicates in each location/`growing system". Percent emergence and seedlings with primary infections were recorded at BBCH 12-13. In average of the three locations 2,5 % and 2.1 % barley seedlings were infected when grown in conventional and organic fields, respectively. In oats, 2,0 % and 0,8 % infected seedlings were recorded in conventional and organic fields, respectively. Similar experiments will be carried out in 2006 and results from this will also be presented.
Forfattere
Guro BrodalSammendrag
Det er ikke registrert sammendrag
Forfattere
Guro BrodalSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Twenty-five tree species were recorded as hosts for five European Armillaria species in studies on forest ecosystems in Serbia. Armillaria was most frequently isolated from the conifers Picea abies and Abies alba and from the deciduous trees Fagus moesiaca and Quercus petraea. A. mellea and A. gallica coexisted in hardwood forests in northern and central parts of Serbia, while A. ostoyae and A. cepistipes were mostly present in coniferous forests in the southern mountain region of Serbia. The distribution depended on the Armillaria species, altitude, and the forest type.
Sammendrag
To identify chemical resistant markers induced by fungal or mechanical injury, young trees of Scots pine (Pinus sylvestris) were subjected to inoculations of blue stain fungi associated with the pine shoot beetles Tomicus piniperda and T. minor. Among the 20 trees selected for chemical analyses, 16 were divided into four groups: one as control and three were pretreated by wounding only, or by inoculation with either the blue stain fungus Leptographium wingfieldii or Ophiostoma canum.Four wk after pretreatment, all 16 pretreated trees were mass-inoculated with L. wingfieldii. The absolute and relative amounts, as well as the enantiomeric compositions of monoterpene hydrocarbons in the phloem, were determined via a small sample of the phloem before and after the pretreatment and mass inoculation, by using two-dimensional gas chromatography (2D GC) and GC-mass spectrometry (MS).After mass inoculation, the absolute amounts of most of the monoterpenes decreased in the phloem sampled 20 cm from the fungal infection, and were higher in the phloem sampled within the infected reaction zone.The relative amounts of both ()--pinene and ()-limonene increased in phloem samples taken 20 cm above the fungal inoculation in the preinoculated trees compared with phloem sampled from the remaining four control trees. The enantiomeric compositions of -pinene and limonene changed, after fungal growth, at defined distances from the inoculation site: the proportion of the ()-enantiomers was highest in the phloem sampled 20 cm from the fungal inoculation.Four wk after pretreatment, monoterpene production in the phloem at the site of inoculation was more enhanced by L. wingfieldii than by O. canum. However, the different virulence levels of the fungi did not affect the enantiomeric composition of the monoterpenes. The biosynthesis of monoterpene enantiomers is discussed in relation to induced pathogen resistance.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag