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
Forfattere
Tor J. JohansenSammendrag
Dormancy in a potato tuber prevents sprout growth even under optimal sprouting conditions and is the first stage in the physiological ageing process. The intensity and duration of this phase differs between genotypes (cultivars) and may also be affected by environmental conditions both during tuber bulking and early storage. The current study aimed at finding how simulated high latitude growth conditions influence dormancy and the physiological age of tubers to be used as seed potatoes. In a controlled climate at natural light conditions, tubers grown at a low temperature (9°C) had 2-3 weeks shorter dormancy than tubers grown at higher temperatures (15 and 21°C). In tubers grown at artificial light conditions, day-lengths (12, 18 or 24 h) did not affect dormancy significantly. A post-harvest treatment with a low temperature (one month at 4°C and subsequently 18°C) reduced dormancy by 2-3 weeks in tubers from the highest growth temperatures (15 and 21°C) in comparison with constant 18°C post-harvest. After the lowest growth temperature (9°C) the duration of dormancy was not affected by post-harvest temperature treatments. Physiological age was determined by sprouting characteristics after winter storage. At this stage the sprouting capacity was highest in tubers originating from the lowest and the highest growth temperatures. Further, the number of sprouts per tuber was higher in tubers grown at 9°C than at 15 or 21°C. These results were not correlated with duration of dormancy after the various treatments, suggesting that temperatures may affect dormancy and physiological ageing independently. The present results show that dormancy may be shortened by low grow temperatures, and similarly by low post-harvest temperatures at higher growth temperatures.
Sammendrag
The main goal of this study was to develop an alternative bedding material for cattle and sheep based on locally produced woodchips from birch trees and Sphagnum peat in Northern Norway. Four litter mixtures; 2.5 and 5.0 cm woodchips, with and without 20 % peat of total volume were studied in A) Four pens sized 20.4 m2 with two cattle each, ie one pen per treatment; B) Eight pens sized 21.2 m2 with seven ewes each, ie two pens per treatment, and two similar sheep pens with deep straw (barley) as controls. The number of lying animals was counted in 10 minutes’ intervals from 6 pm to 6 am for two consecutive days and the mean number of animals lying simultaneously per pen and hour, was calculated. The cleanliness of the animals was assessed within three separate body sections (legs, side, rear) using a scale from 0-2 points for each body part (0 p=clean, 6 p=dirty). The proportion of animals lying simultaneously per pen and hour and individual cleanliness scores were analysed by GLM. No differences in lying behaviour and cleanliness between the four woodchips mixtures were found, neither for sheep nor cattle. However, straw bedding resulted in the least dirty ewes (P
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Bente Kirkhus Britt I.F. Henriksen Aina Lundon G.I. Borge J-E Haugen G. VogtSammendrag
Camelina is an underexploited oilseed crop that may be well suitable for cropping innorthern areas. The oil is particularly high in the omega-3 fatty acid alpha-linolenic acid (C18:3n-3). The aim of the present study was to evaluate the potential for secure production of high quality edible oil from organically grown camelina (Camelina sativa L. Crantz), focusing on the effects ofenvironmental parameters on oil content, fatty acid composition and contents of phytosterols and tocopherols. Field experiments with pre-crop barley were conducted in the growing seasons 2007, 2008 and 2009. Trials were fully randomized with two levels of Nitrogen (N) fertilization, 0 and 120 kg total Nha-1, and two levels of Sulphur (S) fertilization, 0 and 20 kg total S ha-1. Additional experiments were performed in 2009 in order to evaluate the effects of replacing pre-crop barley with pre-crop pea. Crude oils were obtained by usinga pilot press and the fatty acid composition and contents of phytosterols and tocopherols were analyzed by GC-MS and LC-MS. The results showed significantseasonal variations in the contents of fatty acids, tocopherols andphytosterols. Furthermore, significant effects of N-fertilization were observed, with increased contents of C18:3n-3, erucic acid (C22:1) and γ-tocopherol at the highest level of N-fertilization. Pea compared to barley as pre-crop also increased the content of C18:3n-3. There were no effects of S-fertilization. Principal component analysis revealed positive correlations between the contents of C18:3, C22:1, γ-tocopherol and phytosterols, in particular brassicasterol. In conclusion, camelina seems to be well suitable for organic cropping. The oil quality was influenced by season and N-fertilization, still, the variation in nutrient content was small.
Forfattere
Christer MagnussonSammendrag
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.
Forfattere
Ricardo HolgadoSammendrag
Cyst nematodes, Heterodera spp. are known world-wide as parasites of cereals and grasses. Norwegian surveys have revealed that nematodes belonging to the H. avenae complex occur throughout the country; our studies have combined morphology, protein variability (IEF), bio-tests and internal transcribed spacers (ITS3 and ITS5) for the identification of Heterodera populations. Our results showed some divergences between techniques in species identity of some of the studied populations H. avenae is the most common species followed by H. filipjevi (Holgado et al., 2009).. Several populations of H. filipjevi west did not reproduce in oat differentials. In this case both the morphology and protein patterns rather indicated these populations to belong to H. pratensis. In this study a population from Brekstad differed from all other populations in its morphology, and the protein pattern was close to H. mani. This population was collected from barley, and in the pathotype test it was virulent on several barley cultivars. Mathews, 1971reported that H. mani did not reproduce on cereals while (Cook, 1982) indicates that some barley cultivars can serve as hosts. Surprisingly the ITS studies indicated the Brekstad population to be close to H. avenae. This population is in many ways strikingly different from H. avenae, and this result may indicate a need to revise the present gene library of H. avenae. It also demonstrates the need for using several techniques in species identification. In our study the least degree of divergent results on nematode identity is between morphology and IEF.
Forfattere
Ricardo Holgado Christer MagnussonSammendrag
Cyst nematodes, Heterodera spp. are known world-wide as parasites of cereals and grasses. Norwegian surveys have revealed that nematodes belonging to the H. avenae complex occur throughout the country; our studies have combined morphology, protein variability (IEF), bio-tests and internal transcribed spacers (ITS3 and ITS5) for the identification of Heterodera populations. Our results showed some divergences between techniques in species identity of some of the studied populations H. avenae is the most common species followed by H. filipjevi (Holgado et al., 2009).. Several populations of H. filipjevi west did not reproduce in oat differentials. In this case both the morphology and protein patterns rather indicated these populations to belong to H. pratensis. In this study a population from Brekstad differed from all other populations in its morphology, and the protein pattern was close to H. mani. This population was collected from barley, and in the pathotype test it was virulent on several barley cultivars. Mathews, 1971reported that H. mani did not reproduce on cereals while (Cook, 1982) indicates that some barley cultivars can serve as hosts. Surprisingly the ITS studies indicated the Brekstad population to be close to H. avenae. This population is in many ways strikingly different from H. avenae, and this result may indicate a need to revise the present gene library of H. avenae. It also demonstrates the need for using several techniques in species identification. In our study the least degree of divergent results on nematode identity is between morphology and IEF.
Forfattere
Ricardo HolgadoSammendrag
In 1955 the potato cyst nematode was recorded for the first time in Agder. This detection produced the initial legislation of PCN control, and was implemented based on the statutory regulation of 1916. Since 1956 PCN was given quarantine status in infested agricultural land and home gardens. Official controls of certified seed potatoes started in 1939. Each year about 3000 soil samples are analyzed for PCN to clear areas for certified seed potato production. These areas are so far free of PCN. The total acreage with seed potatoes in 2009 was 813.7 Ha. Extensive surveys started in 1955; and were carried uninterrupted until the end of the 1990ties. These surveys included producing potato agricultural land and home gardens. In 2009 a new national survey program for the principal potato districts has started, the surveys is aimed to update the PCN occurrence. The surveys will continue during the subsequently years until all major potato areas will be cover. Statutory regulations for PCN from 1956-2010 to Support to Norwegian Food Safety Authority The regulations have without doubt contributed in preventing PCN infestations in the seed potato areas, and probably also prevented further spreading of wPCN and virulent yPCN as each the find has been placed under quarantine. Permanent grass as a statutory regulation in home garden plots may have contributed to reduce the spread of wPCN to commercial fields. The regulations have most probably made possible the early reduction in use of chemical fumigants, organophosphates or carbamate nematicides. These chemicals have not been used since the early 1970s. The domestic production of seed potato has been kept free of PCN by frequent inspections and analyses for more than 50 years. The fact that farmers are not allowed to import seed potatoes adds to the level of security. New project Studies on the biology of potato cyst nematodes (Globodera spp.) under Nordic conditions for improving management and regulation in Norway. To increase the scientific basis for amending the management system for PCN, Globodera spp under Nordic conditions.
Forfattere
Ricardo HolgadoSammendrag
In 1955 the potato cyst nematode was recorded for the first time in Agder. This detection produced the initial legislation of PCN control, and was implemented based on the statutory regulation of 1916. Since 1956 PCN was given quarantine status in infested agricultural land and home gardens. Official controls of certified seed potatoes started in 1939. Each year about 3000 soil samples are analyzed for PCN to clear areas for certified seed potato production. These areas are so far free of PCN. The total acreage with seed potatoes in 2009 was 813.7 Ha. Extensive surveys started in 1955; and were carried uninterrupted until the end of the 1990ties. These surveys included producing potato agricultural land and home gardens. In 2009 a new national survey program for the principal potato districts has started, the surveys is aimed to update the PCN occurrence. The surveys will continue during the subsequently years until all major potato areas will be cover. Statutory regulations for PCN from 1956-2010 to Support to Norwegian Food Safety Authority The regulations have without doubt contributed in preventing PCN infestations in the seed potato areas, and probably also prevented further spreading of wPCN and virulent yPCN as each the find has been placed under quarantine. Permanent grass as a statutory regulation in home garden plots may have contributed to reduce the spread of wPCN to commercial fields. The regulations have most probably made possible the early reduction in use of chemical fumigants, organophosphates or carbamate nematicides. These chemicals have not been used since the early 1970s. The domestic production of seed potato has been kept free of PCN by frequent inspections and analyses for more than 50 years. The fact that farmers are not allowed to import seed potatoes adds to the level of security. New project Studies on the biology of potato cyst nematodes (Globodera spp.) under Nordic conditions for improving management and regulation in Norway. Major goal is to increase the scientific basis for amending the management system for PCN, Globodera spp under Nordic conditions.
Forfattere
Ricardo HolgadoSammendrag
mest avanserte og fremgangsrike planteparasitter. PCN ble påvist i Europa av Kühn i 1881, og i 1923 erklærer Wollenweber den som egen art. Stone i 1973 skiller PCN i to arter. Gul PCN (Globodera rostochiensis) og hvit PCN (G. pallida). I Norge ble PCN først påvist 1955 i Agderfylkene. PCN har spredt seg raskt og i1993 ble de første funn gjort i Nord-Trøndelag. På verdensbasis er PCN funnet utbredt i 23 land og har en begrenset forekomst i 42 land, og i tillegg er det 130 land det ikke er blitt påvist enda. Både gul og hvit PCN er klassifisert som karanteneskadegjørere i 106 respektive 55 land. I de siste årene har PCN blitt påvist i Australia, Canada og USA, som på nytt satt fokus på hvor lett PCN kan spres og hvilke nasjonale konsekvenser PCN har. De plantesanitære og økonomiske konsekvensene av PCN er betydende. I EU vil PCN bli regulert i det nye EU direktivet 2007/33/EC som implementeres nå. Formålet med direktivet er å bergrense og kontrollere spredningen til PCN. I direktivet gjøres det ingen forskjell mellom gul og hvit PCN, det nevnes at arealer for settepotet og planter til videre dyrking må ha en offisiell dokumentasjon om PCN status, det skal årlig gjennomføres offisiell prøvetaking av 0,5 % av arealet av felt for produksjon av annen potet enn settepotet. Smittede felt får ikke brukes til produksjon av settepotet eller planter til videre dyrking. Bekjempelsestiltak iverksettes på smittede felt som skal brukes til produksjon av annen potet enn settepotet. Ved resistensbryting skal PCN populasjonen rasetestes. Det skal sendes en årsrapport til EU om tiltak som iverksettes i hvert land. I dag benyttes nematicider for å kontrollere PCN, og samtidig disponeres mye resurser for å foredle sorter med resistens.