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.
2011
Sammendrag
The osmotic method has been used for many years in Norway and Sweden as a routine method for detection of Pyrenophora teres (anamorph Drechslera teres) and P. graminea (anamorph D. graminea) on barley. The method is based on the ability of Pyrenophora spp. to produce red pigments. However, it cannot distinguish between P. teres and P. graminea because they produce the same pigment. A validation study has been carried out with the aim to provide the necessary documentation for including the method in the International Rules for Seed Testing (ISTA Rules). Seven laboratories participated and each tested 3 x 300 seeds of three barley seed lots. Analyses of the results demonstrate that the method gives sufficient repeatability and there is no particular problem with this test at a laboratory level. Furthermore, in previous studies with the osmotic method organized by a Nordic working group, it has been shown that the osmotic method easily gives reproducible results for Pyrenophora teres/P. graminea in barley when used by experienced laboratories. Moreover, the osmotic method is well suited for routine analyses because it is quick and easy to carry out. The study showed, that if used correctly and with proper equipment the osmotic method for detection of Pyrenophora teres/P. graminea is easy to perform and it showed good conformity amongst laboratories.
Sammendrag
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Sammendrag
“Verdens beste bær dyrkes i Nord-Norge” sies det. Det nordlige klimaet med lange dager og lave temperaturer gir søtere, mer fargesterke og smakfulle bær. Dette vet forbrukerne i nord å sette pris på, spesielt når det gjelder bær til friskkonsum. I dag er landsdelen langt fra selvforsynt med hagebær. Flere og større dyrkere av arter som jordbær, solbær, stikkelsbær, bringebær og rips må til for å kunne dekke en større andel av eget marked. I de tre nordligste fylkene bor det nesten en halv million mennesker, og de fleste av disse bor i byer og større tettsteder med gode forhold for salg av lokalproduserte bær. Hva må gjøres for at den patriotiske nordlendingen kan få kjøpe lokale bær?
Sammendrag
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Sammendrag
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Forfattere
Kjell Andreassen Volkmar Timmermann Nicholas Clarke Ingvald Røsberg Halvor Solheim Wenche AasSammendrag
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Sammendrag
Nematodes, commonly known as round worms, are the most common multicellular animals on planet Earth. After 1000 million years of evolution members of the phylum Nematoda have a high bionomic diversity. As habitants of the soil and rhizosphere nematodes are involved en energy fluxes, and affect carbon and nutrient cycles. As plant parasites, either alone or in synergism with other pathogens, nematodes are responsible for plant disease complexes and major crop losses. A growth depression in a field of potato (Solanum tuberosum) cv. Saturna [resistant to pathotype Ro1 of potato cyst nematode (PCN) Globodera rostochiensis], suggestive of potato cyst nematode damage, was detected in Grue, eastern Norway. Analyses of soil samples did not detect PCN, but demonstrated the occurrence of a large number of lesion nematodes Pratylenchus penetrans .Tubers from the depressed part of the field had severe symptoms similar to those caused by the common scab bacterium Streptomyces scabies. Potato yield was reduced by 50% in the affected area of the field. Transect-sampling showed plant growth to be negatively correlated with densities of P. penetrans and suggested a damage threshold of potato to the nematode of 100 specimens per250 g of soil. Common scab (Streptomyces scabies) occurred frequently in the affected area. P. penetrans was present in roots, underground stems, stolons and tubers. Tubers from the depressed part of the field had severe symptoms similar to those caused by the common scab bacterium. In tubers, nematodes were detected inside cross-lesions typical symptoms of common scab, and occurred also in the outermost 0.5 mm tissue associated with such lesions. In pots with sterile sand, micro-tubers of potato cv. Saturna, produced from meristems, were grown in a green-house infected with, P. penetrans, S. scabies, and a combination of P. penetrans and, S. scabies. P. penetrans alone induced tuber lesions similar to those of common scab. Also, the combined inoculation of the bacterium and the nematode seemed to enhance symptom expression. Similar scab symptoms, in connection with lesion nematode infections, have been observed on potato tubers cv. Oleva, which also is relatively tolerant to common scab. Symptomatic tubers cv. Saturna first stored at 4o C for 20 weeks were transferred to pots with sterile sand and grown for 3 months in the green-house. In these cultures P. penetrans was first detected in soil 8 weeks after planting. Examination at harvest of soil, roots, stolons, tubers demonstrated symptoms typical of P. penetrans. Interestingly, P. penetrans survives storage of potatoes, from which new infections may develop. Hence, potato tubers do appear to be an important means for the spread of P. penetrans to new areas. The fact that the symptoms induced by this nematode may be mistaken for symptoms of common scab suggests that the frequency of S. scabies might have been overestimated in regular surveys. Infections by P. penetrans have important implications for scab control. This pertains in particular to recommended maintenance of high soil moisture at and during 4-9 weeks after tuber set. If symptoms are related to nematode infection rather than to the scab bacterium, this recommendation would allow for a rapid build-up of lesion nematodes resulting in a decrease in both yield and marketability of the tubers. Further studies are needed to investigate the extent of this problem.
Sammendrag
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Forfattere
Ragnhild Nærstad Arne Hermansen Vinh Hong Le Grete Lund Abdelhameed Elameen May Bente BrurbergSammendrag
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Forfattere
Merete Wiken Dees Panu Somervuo Erik Lysøe Arild Sletten Jari P. T. Valkonen Arne HermansenSammendrag
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