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.
2009
Forfattere
Ricardo Holgado Stig Andersson Janet Rowe Ian Clark Christer MagnussonSammendrag
Cereal cyst nematodes (CCN), Heterodera spp. are well-known world-wide as parasites of cereals. In Scandinavia H. avenae is the most common species and occurs in the pathotypes, Ha11 and Ha12, and the additional pathotypes H. avenae-Knislinge, H. avenae-Ringsåsen and H. avenae-Våxtorp. H. filipjevi, which occurs in the two pathotypes, "East" and "West" is less common than H. avenae. For several years it has been known that resistance to cereal cyst nematodes may be found in some commercial cultivars, although no conscious breeding for resistance has been attempted. In 2004 and 2005 a majority of cereal cultivars on the Norwegian market were tested for susceptibility/resistance towards H. avenae pathotype Ha11, H. avenae pathotype "Våxtorp" and H. filipjevi pathotype "West" The test program included 30 cultivars of barley, 23 cultivars of oats and 6 cultivars of summer wheat. Resistance against Ha11 was found in 5 barley, 3 oat cultivars and in 1 wheat cultivar. Resistance against H. avenae pathotype "Våxtorp" was not present in barley, but 4 oat cultivars and 1 wheat cultivar were resistant. For H. filipjevi "West" resistance was not detected in wheat, but in 6 barley and 13 oat cultivars. Obviously the variability in CCN is larger than generally anticipated. In Norway management systems based on careful nematode identification and good knowledge of suitable resistant cultivars are in operation. Resistant barley is generally recommended when nematode populations are high due to its high tolerance compared to resistant oats. Farmers implementing this program have reported increased cereal yields of in average 1000 kg /ha. It has been calculated that by implementing this program in full the county of Vestfold could make an economic gain of 800 000 € annually. In perspective of increasing damage from CCN world-wide the recognition of its genetic variability is instrumental for successful control.
Forfattere
Yngve RekdalSammendrag
Vegetasjonskart gjev eit bilete av den mosaikken av vegetasjonstypar som det naturlege plantedekket består av. Ein vegetasjonstype er ei karakteristisk samling planteartar som vil gå att på lokalitetar med like veksetilhøve. Ei oversikt over utbreiinga av vegetasjonstypar gjev oss på denne måten informasjon også om variasjonen i økologiske faktorar (klima, næring og vatn i jorda, snødekke og kulturpåverknad) i eit område. I tillegg kan kvar vegetasjonstype tilleggast eigenskapar med omsyn til ulik ressursutnytting og bruk (beite, slitestyrke for ferdsel, artsmangfald m.m.). Kring innsjøen Savalen i Tynset og Alvdal kommunar er det vegetasjonskartlagt eit areal på 124 km² (108 km² er landareal) på oppdrag frå landbruksetaten i kommunane. Viktigaste målsettinga med kartlegginga er å lage eit grunnlag for planlegging av beitebruk i området. Kartlegginga er gjort etter Skog og landskap sin instruks for vegetasjonskartlegging i M 1:20 000 - 50 000. Det er framstilt vegetasjonskart og avleia temakart for sauebeite og storfebeite, samt kart over viktige naturtypar for biologisk mangfald. Berggrunnen i området er dominert av fyllitt, glimmerskifer og amfibolitt. Dette er bergartar som er lett vitterlege og vanlegvis gjev god tilgang på plantenæring, sjøl om ein del variasjonar vil finnast. Med unnatak av dei mest eksponerte høgdene, har lausmassar jamn og ofte tjukk dekning i heile området. Mykje av dette er morene som gjennomgåande er grovkorna. Området har eit typisk innlandsklima med låg vintertemperatur og høg sommartemperatur i høve til høgda over havet. Nedbøren er låg med kring 400 mm i årsnedbør. 78% av kartleggingsområdet ligg under skoggrensa som går kring 950 m o.h. Opp til barskoggrensa vel 800 m o.h blir vegetasjonen dominert av fattig furuskog, mest lav- og lyngrik furuskog, men med innslag av blåbærfuruskog på friskare parti. Over barskogen kjem eit band av bjørkeskog opp til skoggrensa kring 950 m o.h. Bjørkeskogen er mest av blåbærtype, men innslag finst av rikare skog. Skogar av lav- og lyngrik type utgjer samla 44% av arealet under skoggrensa, blåbærskogar 27% og engskogar 7%. På vestsida av Savalen ligg store myrareal. Mykje av myrarealet er rik- eller ekstremrik myr. Mange setrer ligg i området.
Sammendrag
Transport and turnover of dissolved organic carbon (DOC) is important in the C cycle of organic soils. The concentration of DOC in soil water is buffered by adsorption to the soil matrix, and has been hypothesized to depend on the pool size of adsorbed DOC. We have studied the effect of frequent artificial excessive leaching events on concentration and flux of DOC in shallow, organic rich mountain soils. Assuming a constant Kd value for DOC adsorption to the soil matrix, we used these data to assess the change in the pool of adsorbed (or potential) DOC in the soil. The study involved manipulation of precipitation amount and frequency in summer and autumn in small, heathland catchments at Storgama, southern Norway. The shallow soils (16 to 34 cm deep on average) limit the possibility for changes in water flow paths during events. The mini-catchments range in size from 75 m2 to 98 m2. Our data show that after leaching of about 1.2 g DOC m-2 the DOC concentration in runoff declines by approximately 50%. From this we conclude that the pool size of adsorbed potential DOC in the shallow soils at any time is of the order 2-3 g m-2. Frequent episodes suggest that the replenishment rate, which depends on the decomposition rate of soil organic matter, is fast and the potential DOC pool could be fully restored probably within days during summer, but with some more time required in autumn, due to lower temperatures. Both pool size of potential DOC and replenishment rate are seasonally dependent. The pool of potential DOC, and thus the DOC concentration in discharge, is at their maximum in the growing season. However, under non-leaching conditions, the concentration of DOC in soil water and thus the pool size of potential DOC seems to level off, possibly due to conversion of DOC to less reversibly bound forms, or to further decomposition to CO2.
Forfattere
Tatsiana EspevigSammendrag
Preliminary results from the study "Effects of metabolic changes during cold hardening on freezing survival of Agrostis spp." were presented. The objectives of the trial were: (1) to compare freezing tolerance of velvet bentgrass and creeping bentgrass, (2) to quantify carbohydrate and protein changes during the two consecutive phases of cold acclimation in these species, and (3) to compare one direct and two indirect methods for determination of LT50 in turfgrasses. Three (of four) treatments representing different phases of cold acclimation were compared: (i) nonacclimated (NA) plants maintained at 18 °C/12 °C (day/night); (ii) plants acclimated at 2 °C for 2 wk and 250 μmol m-2 s-1 for 12 h photoperiod (A2); and (iii) as treatment (ii) but for 4 wk (A4). Plants exposed to additional sub-zero acclimation in the dark at -2 °C for 2 wk (A4+SZA2) were under acclimation treatment at that time. Results regarding 1st and 3rd objectives were discussed. Acclimation at 2 ºC significantly improved freezing tolerance of both species, but differences between species were not significant. The LT50 for plants subjected to A2 and A4 were 4 and 6 °C lower, respectively, compared to NA plants. Crown viability test had a good correlation with the LT50 based on whole plant survival. Electrolyte leakage underestimated freezing survival ability in Agrostis spp.
Forfattere
Hans StabbetorpSammendrag
Det er ikke registrert sammendrag
Populærvitenskapelig – Sorter og sortsprøving 2008
Mauritz Åssveen, Jan Tangsveen, Ingrid Hedum, ...
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Crown rot caused by Phytophthora cactorum is an important disease in commercial strawberry production worldwide. The level of resistance varies greatly between cultivars, and many of the most commonly grown cultivars are quite susceptible to P. cactorum. Adequate soil drainage, clean planting material and use of highly resistant cultivars are the most important measures against crown rot. Previous work at our institute has involved evaluation of methods to screen for resistance, cultivar and progeny screening, and use of induced resistance against the disease. That work also included a genetic study of P. cactorum isolates from various host plants and different geographic origins. P. cactorum has many host plants, but it turned out that isolates causing crown rot of strawberry differs genetically from those with other host origin. A project was recently initiated, where one of the main goals has been to identify molecular markers for resistance against P. cactorum in strawberry. Genotypes of diploid Fragaria species have been screened for resistance, and the progeny from a cross between a susceptible and a resistant genotype will be evaluated by the end of this year. Commercially grown strawberry is very heterozygous and octoploid. Diploid Fragaria species are therefore useful as model organisms. The Fragaria genus has a conserved organisation, and hopefully information obtained from the study of diploid genotypes can be transferred to cultivated Fragaria x ananassa and possibly to other important crop plants in Rosaceae.
Forfattere
Ignace Godonou Segolene Leclercq Ghislain Tepa Yoto Braima James May-Guri SaethreSammendrag
Aphids are recognised worldwide as economically important pests in vegetable production systems. Synthetic pesticides are used against aphids and pose a great risk to the environment, human health and beneficial biodiversity. Aphid species, their natural enemies, their vegetable and weed hosts were poorly documented in Benin. A study was undertaken at 31 vegetable production sites across Benin to identify the aphid species, their host plants, and their natural enemies. The level of aphid infestation and damage to vegetables were also recorded. 17 out of 31 vegetable species surveyed were commonly infested and damaged by aphids. Aphis gossypii, Aphis craccivora and Lipaphis erysimi were recorded on a wide range of vegetable species, while Myzus persicae where recorded on Brassica rapa and Solanum macrocarpon only. 44 weeds where recorded associated with vegetables and 25 where infested with aphids. Commelina benghalensis, Trianthema portulacastrum and Euphorbia hirta were the weeds heavily infested. The most commonly encountered aphid predators where Cheilomenes propinqua, Cheilomenes sulphurea, and Ischiodon aegyptius. The widely distributed aphid parasitoid Lysiphlebus testaceipes were often found attacking A. gossypii and A. craccivora. Further studies will be carried out to assess the potential of these natural enemies in an integrated pest management strategy against aphids.
Forfattere
Per Stålnacke Annelene Pengerud Marianne Bechmann Josette Garnier Christoph Humborg Vladimir NovotnySammendrag
The major objective of this study was to compile and examine empirical relationships between the driving forces and pressures that affect nitrogen cycling. Special attention was paid to riverine loads, fluxes, and concentrations of nitrogen in relation to agricultural factors (e.g., land use and fertilisers) at various spatial scales (plot, field, catchment, river basin, nation, region, continent, and world). Results of the present analyses and assessments reported in the literature indicate that at global, continental and inter-river basin scales, the level of riverine nitrogen loads (pressures) can be readily derived from simple empirical relationships with driving forces like population density and agricultural factors (e.g., proportion of arable land and fertiliser use). It seems that statistically derived relationships do not hold or are much weaker at the scales of single river basins and smaller catchments, whereas nitrogen losses appear to be correlated with fertiliser use at the smallest scales (plot and field). It is important to recognize this spatial nutrient paradox, particularly when such functional relationships are applied in the contexts of management and decision making. The implications for management are given further consideration in this paper.
Forfattere
Geir Kjølberg Knudsen Marco TasinSammendrag
Abstract: Apple fruit moth Argyresthia conjugella (Zeller) (Lepidoptera: Argyresthiidae) is the most important insect pest in apples in Fennoscandia. Its principle host is the masting forest three rowan Sorbus aucuparia. Damage to apple occurs only in intermasting years when rowan produces low crop. A monitoring tool is needed to detect the timing of female migration to apple in order to precisely apply control measures. Volatile plant compounds may be used to trap migrating females searching for the alternative host during intermasting years. In this study we present data from field monitoring experiments. In 2007 we carried out a field test in apple with the aim to screen for behaviorally active compounds beside those already described by Bengtsson et al. (2006). In traps baited with three component blends we found four compounds that could be regarded as synergists. These compounds were in 2008 tested both in rowan and apple. We detected insects by both visual inspections and trapping in a rowan stand, whilst only traps baited with the candidate compounds could detect migrating insects in apple orchards. The number in apple however was low due to the fact that 2008 was a low-attack season and the majority of the moths remained in the rowan stands. Improvements of blend composition for field monitoring may be achieved by additional field tests in damage years in combination with ongoing wind tunnel studies.