Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2021

Abstract

Occasionally, high mycotoxin levels are observed in Norwegian oat grain lots. The development of oat varieties with improved resistance to Fusarium and mycotoxins is therefore highly valued in order to increase the share of high quality grain into the food and feed industry. The Norwegian project “SafeOats” (2016-2020) aimed to develop resistance-screening methods to facilitate the phase-out of Fusarium-susceptible oat germplasm, as well as to give new insight into the biology of Fusarium langsethiae and HT2+T2 accumulation in oats. In naturally infested as well as in inoculated field trials, the relative ranking of oat varieties according to Fusarium graminearum/DON content did not resemble the ranking according to F. langsethiae/HT2+T2 content. One variety regarded as moderate resistant to Fusarium according to studies of DON content, was susceptible to F. langsethiae and thus at high risk for HT2+T2 contamination. Screening of resistance to F. langsethiae/HT2-T2 should therefore be routinely applied in breeding programs in addition to the already established screening of resistance to F. graminearum/DON. The incidence of F. langsethiae in a selection of oat seed lots used for commercial sowing showed a similar ranking of varieties as in the field trials. On average, the fungus was observed on 5% of the kernels in 168 seed lots tested during 2016-2018. No indication of transmission of F. langsethiae from germinating seed to seedling was found in a study with germination of naturally infected seeds. We investigated whether removing of small kernels by size sorting could be a method to reduce the content of mycotoxins in oat grain. For several of the mycotoxins including HT2+T2, the concentrations were considerably higher in the small kernel fraction compared to unsorted grain. Our results demonstrate that the level of mycotoxins in unprocessed oat grain can be reduced by removing small kernels. The results from SafeOats will benefit consumers nationally and internationally by providing tools to increase the share of high quality grain into the food and feed industry. The project was financed by The Agriculture and Food Industry Research Funds /Research Council of Norway with support from the industry partners Graminor, Lantmännen, Felleskjøpet Agri, Felleskjøpet Rogaland & Agder, Fiskå Mølle Moss, Norgesmøllene, Strand Unikorn/Norgesfôr and Kimen Seed Laboratory.

Abstract

Simple Summary The bird cherry-oat aphid and the fungal plant pathogen causing stagonospora nodorum blotch (SNB) are common pests of wheat. Plants are under constant attack by multiple pests and diseases but there are limited studies on the interaction between several pests on wheat. We therefore conducted controlled greenhouse and laboratory experiments to determine how these pests affected each other on a wheat plant. We found that aphid feeding predisposed wheat to fungal disease, but that aphids preferred and reproduced better on leaves that had not been infected by the fungal pathogen. These results are important to understand the interactions between multiple pests on wheat and how to develop new control strategies in future integrated pest management (IPM). Abstract Wheat plants are under constant attack by multiple pests and diseases. Until now, there are no studies on the interaction between the aphid Rhopalosiphum padi and the plant pathogenic fungus Parastagonospora nodorum causal agent of septoria nodorum blotch (SNB) on wheat. Controlled experiments were conducted to determine: (i) The preference and reproduction of aphids on P. nodorum inoculated and non-inoculated wheat plants and (ii) the effect of prior aphid infestation of wheat plants on SNB development. The preference and reproduction of aphids was determined by releasing female aphids on P. nodorum inoculated (SNB+) and non-inoculated (SNB−) wheat leaves. The effect of prior aphid infestation of wheat plants on SNB development was determined by inoculating P. nodorum on aphid-infested (Aphid+) and aphid free (Aphid−) wheat plants. Higher numbers of aphids moved to and settled on the healthy (SNB−) leaves than inoculated (SNB+) leaves, and reproduction was significantly higher on SNB− leaves than on SNB+ leaves. Aphid infestation of wheat plants predisposed the plants to P. nodorum infection and colonization. These results are important to understand the interactions between multiple pests in wheat and hence how to develop new strategies in future integrated pest management (IPM).

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Abstract

Meldugg, forårsaket av soppen Oidium anacardii, er en viktig sykdom ved produksjon av cashewnøtter. I dette arbeidet er det sett på effekten av ‘bio-spray’ (en blanding av utvalgte mikoorganismer og sirup fra casheweple og/eller sukkerrør) mot meldugg og for å finne den optimale konsentrasjonen av middelet mot sykdommen. To forsøk ble gjennomført; i et skygge-hus med småplanter av cashew og på friland i en ordinær planting. Det var fire behandlinger med ulike konsentrasjoner av bio-spray (10%, 15%, 20% and 25%), i tillegg til behandlinger med sirup (uten mikroorganismer tilsatt) i 5% konsentrasjon eller standard fungicider. Et kontroll-ledd var helt ubehandlet, mens et annet var behandlet med vann. I skyggehuset ble plantene inokulert med smitte fra andre planter, mens forsøkene på friland ble lagt i et felt som tidligere hadde hatt mye meldugg. I skyggehuset ble det foretatt to behandlinger med 15 dagers mellomrom bortsett fra fungicid som ble brukt en gang. På friland ble det foretatt fem behandlinger med enten bio-spray, sirup eller vann med 15 dagers mellomrom, mens standard fungicidbehandling ble utført tre ganger med 21 dagers mellomrom. Prosent blad med angrep og angrepsgrad ble registrert i skyggehuset. På friland ble i tillegg fenologisk stadium og avlingseffekter undersøkt. I skyggehuset ble det lite angrep av meldugg, mens det var betydelig angrep på friland. Det såkalte arealet under sykdomskurven (AUDPC) viste at de ulike konsentrasjonene av bio-spray ikke reduserte meldugg sammenlignet med kontroll-leddene. Det var noe bedre effekt av 15% konsentrasjon sammenlignet med 25%. Behandling med fungicider var signifikant bedre enn de andre behandlingene og var det eneste forsøksleddet som gav god kontroll av meldugg.

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Abstract

The relationship between the ecological success of needle pathogens of forest trees and species richness of co-inhabiting endophytic fungi is poorly understood. One of the most dangerous foliar pathogens of pine is Dothistroma septosporum, which is a widely spread threat to northern European forests. We sampled two Pinus sylvestris sites in Estonia and two in Norway in order to analyse the relations between the abundance of D. septosporum and overall fungal richness, specific fungal species composition, time of season, needle age and position in the canopy. In both countries, the overall species richness of fungi was highest in autumn, showing a trend of increase with needle age. The overall species richness in the second-year needles in Estonia and third-year needles in Norway was similar, suggesting that a critical colonization threshold for needle shed in P. sylvestris is breached earlier in Estonia than in Norway. The fungal species richness in P. sylvestris needles was largely affected by Lophodermium conigenum. Especially in older needles, the relative abundance of L. conigenum was significantly higher in spring compared to summer or autumn. The timing of recruitment and colonization mechanisms of different foliage endophytes are shortly discussed.

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Abstract

In developing countries, over 50% of horticultural crops are lost after harvesting due to absense of or poor postharvest cold storage facilities. Cold storage facility is a critical component of the food supply chain and food security because it can extend the storage period of the perishable products; avoid glut and post-harvest losses, reducing transport bottlenecks. The objective of the study was to design and construct an evaporative cooling system to store horticultural products in a wide range of climatic conditions in Ethiopia. The design integrates direct evaporative cooling system and indirect evaporative cooling system with technical improvements and re-arrangements for continuous operation and handling purpose. After the design and construction work of the cooler was completed, its performance was tested and evaluated without product load at maximum mean annual temperature for five days. Finally, the performance and effect of the cooler on tomato shelf life and quality was evaluated by storing fresh tomatoes inside the cooler shelves. For comparison (control group), randomly selected fresh tomatoes were stored in a basket, which is a standard method that retailer display tomatoes in the market in the study area. A portable evaporative cooler was constructed from locally available and used materials and integrated with new temperature and relative humidity sensors. It had a capacity of 260 Kg (573.2 lb). The evaporative cooler resulted in a reduction in the maximum ambient temperature from 32.8°C (91.6°F) to 23.5°C (74.3°F) in the cooler. As the ambient temperature drops to 21.8°C (71.4°F), the temperature in the cooler reduced to 15°C (59°F). The cooler stabilized the relative humidity between 77- 88%. The newly designed and constructed evaporative cooler reduced the postharvest loss of tomato from 80 % in a traditional basket to 5% in the evaporative cooler. The cooler reduced the postharvest loss of tomato by 94%. It maintained the quality of the fresh tomatoes. In conclusion what we showed in this study was that we have refined the design and constructed a low cost and effective cooling system that can be used by poor retailers of vegetables and fruits. Evaporative cooler is an old and forgotten technology, if the design and construction are refined, it can be used to regulate temperature and relative humidity and used in different purposes especially for those who cannot afford to buy modern thermal regulation technologies.