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.
2020
Sammendrag
Since the European pear (Pyrus communis L.) is a self-incompatible fruit species, synchrony and compatibility between female parts of the mother plant and male gametes from the pollen donor must be fulfilled. Besides pollination and fertilization, normal embryo and zygote development is one of the prerequisites for the satisfactory yields in pears. The main goal of this experiment was to investigate the functionality of embryo sacs and the embryo’s early stages of growth in relation to the fruit set of diploid (‘Celina’) and the triploid (‘Ingeborg’) pear cultivars under specific Norwegian climatic conditions. For this purpose, flowers were collected at the beginning of flowering, and on the third, sixth, ninth, and twelfth days after the beginning of this phenophase for two consecutive years. Ovaries were dehydrated, embedded in paraffin wax, sectioned, stained, and observed under the light microscope. In the analyzed cultivars, results showed different tendencies in embryo sac development and degradation processes, in both experimental years, which is probably due to the genetic background of the examined cultivars. Also, fertilization success and fruit set were higher in the second year of study due to the higher average temperature during the flowering period. Diploid cultivar ‘Celina’ showed much better adaptation to high temperatures in relation to triploid cultivar ‘Ingeborg’.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Anita Smailagic Petar Ristivojevic Ivica Dimkic Tamara Pavlovic Dragana Dabic´ Zagorac Sonja Veljovic Milica Fotiric´ Akšic Mekjell Meland Maja NaticSammendrag
The main focus of this study is to assess radical scavenging and antimicrobial activities of the 11 wood extracts: oak (Quercus petraea (Matt.) Liebl., Q. robur L., and Q. cerris L.), mulberry (Morus alba L.), myrobalan plum (Prunus cerasifera Ehrh.), black locust (Robinia pseudoacacia L.), and wild cherry (Prunus avium L.). High-performance thin-layer chromatography (HPTLC) provided initial phenolic screening and revealed different chemical patterns among investigated wood extracts. To identify individual compounds with radical scavenging activity DPPH-HPTLC, assay was applied. Gallic acid, ferulic and/or caffeic acids were identified as the compounds with the highest contribution of total radical scavenging activity. Principal component analysis was applied on the data set obtained from HPTLC chromatogram to classify samples based on chemical fingerprints: Quercus spp. formed separate clusters from the other wood samples. The wood extracts were evaluated for their antimicrobial activity against eight representative human and opportunistic pathogens. The lowest minimum inhibitory concentration (MIC) was recorded against Staphylococcus aureus for black locust, cherry and mulberry wood extracts. This work provided simple, low-cost and high-throughput screening of phenolic compounds and assessments of the radical scavenging properties of selected individual metabolites from natural matrix that contributed to scavenge free radicals.
Sammendrag
The aim of this study was to evaluate the thinning efficacy of metamitron (Brevis®) as fruitlet thinner compared to ammonium thiosulphate (ATS) and ethephon (Cerone) as flower thinning agents to ‘Rubinstep’ apple. The thinning efficacy of the flower thinning agents was compared to different timings (8-10 and 12-14 mm fruitlet diameters) and dosages (165 and 330 ppm) of the fruitlet thinner metamitron at the experimental farm at Nibio Ullensvang, western Norway (60°19’8.03”N; 6°39’14.31”E) in 2018. Untreated trees and trees manually thinned after June drop were used as reference treatments. Fruit set, yield data and fruit quality parameters for each treatment were recorded. None of the chemical thinning treatments resulted in a significant reduction in the final number of fruits and yield tree-1. Crop load of the untreated trees was almost twice the target crop load of the hand-thinned trees. Ammonium thiosulphate (ATS) was the only chemical thinning treatment that significantly increased fruit weight above the untreated trees, but to a lesser extent than achieved by hand thinning. Qualitative traits of ‘Rubinstep’ apples (ground and over colour, firmness, starch index and soluble solid contents were not correlated with the fruit set. Return bloom of the untreated trees was 50% of the bloom of the previous year. The ammonium thiosulphate-treated trees showed a significant higher percentage return bloom of 122%. Return bloom in all other treatments did not differ significantly from the untreated controls. However, the average values showed a clear trend of a decrease in return bloom in metamitron-treated trees in comparison with the untreated and hand-thinned trees. The exceptionally high levels of solar radiation in May 2018 and the excellent pollination conditions resulting in very high seed numbers fruit-1 are likely the reasons for the lack of thinning efficacy of Brevis®.
Forfattere
Mekjell MelandSammendrag
Det er ikke registrert sammendrag
Sammendrag
Norwegian pear production is low due to climatic limitations, a lack of well-adapted cultivars and suitable pollinizers. However, nowadays it is increasing as a result of newly introduced and bred pear cultivars. Since cross pollination is necessary for high yields and good fruit quality, the aim of this investigation was to find the most suitable pollinizers for the pear cultivars “Ingeborg” (“Conference” × “Bonne Louise”) and “Celina” (“Colorée de Juillet” × “Williams”). Self-pollination of “Ingeborg” and “Celina”, together with “Conference”, “Belle Lucrative”, “Anna”, “Clara Frijs”, “Herzogin Elsa”, “Kristina” and “Fritjof” as potential pollinizers, were studied in this experiment during the 2017 and 2018 seasons in Norway. The success rate of each pollinizer was tested under field conditions, while the monitoring of pollen tube growth was done using the fluorescence microscopy method. All reproductive parameters (pollen germination, number of pollen tubes in the upper part of the style, pollen tube number in the locule of the ovary, number of fertilized ovules, initial fruit set, and final fruit set) in all crossing combinations were higher in 2018 due to much warmer weather. Based on the flowering overlap and success rate of each individual pollinizer and fruit set, the cultivars “Anna” and “Clara Frijs” can be suggested as pollinizers for the cultivar “Ingeborg”, while “Fritjof”, “Anna”, “Kristina” and “Herzogin Elsa” for the cultivar “Celina”. An even distribution of two compatible pollinizers having overlapping flowering times with the main commercial pear cultivar is a general recommendation for commercial pear production.
Forfattere
Mekjell MelandSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Johan A. Stenberg Anders Nielsen Per Hans Micael Wendell Beatrix Alsanius Paal Krokene Christer Magnusson Mogens Nicolaisen Iben M. Thomsen Sandra A. I. Wright Trond RafossSammendrag
ANDERcontrol with the predatory mite Amblyseius andersoni as the active organism is sought to be used as a biological control agent in Norway. ANDERcontrol is intended for use against different mites (such as the two-spotted, fruit-tree, and red spider mite, russet mite,cyclamen mite) and in horticultural crops such as fruits, berries, vegetables, and ornamental. VKM’s conclusions are as follows Prevalence, especially if the organism is found naturally in Norway: Amblyseius andersoni has not been observed in Norway. It has been observed, in low numbers, in southern Sweden and has the capability to enter diapause under unfavourable conditions which suggests the potential for establishing under Norwegian conditions. It is however, the view of VKM that it likely lacks the ability to survive and establish in areas with cold winters and chilly summers, as found in most parts of Norway under current climatic conditions. The potential of the organism for establishment and spread under Norwegian conditions specified for use in greenhouses and open field: The thermal preference of A. andersoni restricts its establishment, and the species has not been observed in Norway. The species is capable of entering diapause, but the lack of records, despite targeted surveys, makes it the opinion of VKM that it is unlikely that A. andersoni will be able to establish in outdoor areas in Norway. However, the lack of information on temperature tolerance of the species constitute an uncertainty factor. The risk of spread from greenhouses is low because no wind or vector are likely to carry the mites from the greenhouse to suitable outdoor habitats, and mite populations in greenhouses do not enter the more cold-tolerant diapause. All conclusions are uncertain due to lack of relevant information regarding the species’ climate tolerance. Any ambiguities regarding the taxonomy, which hampers risk assessment: There are no taxonomic challenges related to the assessment of A. andersoni. Assessment of the product and the organism with regard to possible health risk: VKM is unaware of reports where harm to humans by A. andersoni itself, or associated pathogenic organisms have been observed. Mites may however produce allergic reactions in sensitive individuals handling plant material with high numbers of individuals. There is reason to believe that this holds true also for A. andersoni. Key words: VKM, risk assessment, Norwegian Scientific Committee for Food and Environment, Norwegian Food Safety Authority, biological control, predatory mite
Forfattere
Anders Nielsen Johan A. Stenberg Per Hans Micael Wendell Beatrix Alsanius Paal Krokene Christer Magnusson Mogens Nicolaisen Iben M. Thomsen Sandra A. I. Wright Trond RafossSammendrag
The product Limonica, with the predatory mite Amblydromalus limonicus as the active organism, is sought to be used as a biological control agent in Norway. Limonica is intended for use against western flower thrips (Frankliniella occidentallis), other thrips (e.g. Thrips tabaci), spider mites and whiteflies (e.g. Trialeurodes, Aleyrodes and Bemisia spp.) in protected horticultural crops such as cucumber, sweet pepper, strawberry and ornamentals. The product is not recommended for greenhouse-grown tomatoes. VKM’s conclusions are as follows Distribution, especially if the organism is found naturally in Norway Amblydromalus limonicus has a very wide natural distribution, being reported from New Zealand, Australia South America, Central America, and North America as well as Hawaii. It has also recently established populations in crop productions and non-crop vegetation in Catalonia, North Eastern Spain. Amblydromalus limonicus have not been observed in Norway. The species seems not to have the capability to enter diapause under unfavourable conditions and it is the view of VKM that it likely lacks the ability to survive and establish in areas with cold winters and chilly summers, as found in most parts of Norway under current climatic conditions. The potential of the organism for establishment and spread under Norwegian conditions specified for use in greenhouses and open field The thermal preference of A. limonicus restricts its establishment, and the species has not been observed outdoors in Norway. As the species is incapable of entering diapause it is the opinion of VKM that it is unlikely that A. limonicus will be able to establish in outdoor areas in Norway. However, the lack of detailed information on temperature tolerance of the species constitutes an uncertainty factor. The risk of spread from greenhouses is low because no wind or vector are likely to carry the mites from the greenhouse to suitable outdoor habitats. However, mites that have escaped from a greenhouses to may spread in the nature. All conclusions are uncertain due to lack of relevant information regarding the species’ climate tolerance. Its origin and current distribution suggest that it cannot survive cold winters. Any ambiguities regarding taxonomy that hamper risk assessment There are no taxonomic challenges related to the assessment of A. limonicus. Assessment of the product and the organism with regard to possible health risks VKM Report 2020: 13 8 VKM is unaware of reports where harm to humans has been observed, whether by A. limonicus itself. Mites may, however, produce allergic reactions in sensitive individuals handling plant material with high numbers of individuals. There is reason to believe that this holds true also for A. limonicus. Key words: VKM, risk assessment, Norwegian Scientific Committee for Food and Environment, Norwegian Food Safety Authority, biological control, predatory mite