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
Norwegian pear (Pyrus communis L.) production has been in decline for the last 25 years. This was mainly because of old cultivars, with low yields and poor consumer appeal, could not compete against strong competition from imported pears, mainly ‘Conference’. Since 1994, the Norwegian breeding company, Graminor Ltd., has released several new pear cultivars, which have been evaluated at NIBIO Ullensvang, western Norway. The first trial was planted in 1999 and included the Graminor Ltd. cultivars: ‘Ingeborg’, ‘Fritjof’ and ‘Anna’, which were bred by the Norwegian University of Life Sciences. In 2002, a second trial was planted including Graminor Ltd. cultivars: ‘Kristina’, ‘Ingrid’ and ‘Celina’ and these were compared against a control, ‘Clara Frijs’. All scion cultivars were grafted on the semi-vigorous rootstock ‘Brokmal’ and grown for 8 years. In both trials, full bloom (~80% of flowers open) took place between 7 May + 3 days and 15 May + 4 days. Flowering was however, completed within a 7-day period in any one year, ensuring adequate overlap in flowering time between all cultivars. Over the final 4-year period all cultivars were evaluated, ‘Anna’, ‘Fritjof’, ‘Kristina’ and ‘Ingeborg’ all had moderate cumulative yields (64.7, 66.2, 36.1, and 30.4 kg·tree-1, respectively). Fruit weight (212 to 183g) and quality of all these cultivars was acceptable (11.2% ≤ TSS ≤ 11.8%; 0.16% ≤ acidity ≤ 0.22%). However, ‘Fritjof’ had many misshapen fruit and exhibited pre-harvest shriveling in several instances making it unacceptable for commercial plantings. ‘Clara Frijs’ and ‘Celina’ cumulative yields were low (12.5 and 21.2 kg per tree, respectively) and fruit were also small (172 to 161 g, respectively). However, due to the attractive cerise-blush ‘Celina’ (trademarked QTee®) pear is now widely planted in Norway and abroad and grafted on Quince rootstocks.
Authors
Milica Fotiric-Aksic B Todic D Dabic Zagorac T Tosti Z Tesic M Natic Mekjell MelandAbstract
No abstract has been registered
Authors
Mekjell Meland U Gasic T Tosti Milica Fotiric-AksicAbstract
No abstract has been registered
Authors
James Kisaakye Hendrika Fourie Danny Coyne Laura Cortada Shirlyne Masinde Sevgan Subramanian Solveig HaukelandAbstract
The banana weevil (BW), Cosmopolites sordidus, is the main coleopteran pest of banana, causing up to 100% yield loss. In this study, we screened 20 isolates of entomopathogenic fungi (EPF) for the management of BW. In the lab, eight Beauveria bassiana isolates caused >50% mortality of the adult BW, whereas Metarhizium anisopliae and Isaria fumosorosea isolates were less pathogenic. B. bassiana isolates ICIPE 648, ICIPE 660 and ICIPE 273 were the most pathogenic, killing ≥80% of adult BW. B. bassiana isolate ICIPE 622 yielded the highest spores per BW cadaver (1.84 × 108 spores), followed by ICIPE 660, ICIPE 273 and ICIPE 648—1.17 × 108, 3.8 × 107 and 3.6 × 107 spores, respectively. ICIPE 273 had the shortest LT50 (5.3 days) followed by ICIPE 648 (9.8 days) and 660 (11.1 days). Similarly, the LC50 values for the three isolates were 5.18 × 107, 5.49 × 107 and 5.2 × 107 spores mL−1, respectively. In the field, ICIPE 273 and ICIPE 648 had the highest (31.3%) and lowest (20.8%) pathogenicity, respectively. This study indicates that the B. bassiana isolates ICIPE 273, ICIPE 648 and ICIPE 660 are potential candidates for the environmentally sustainable management of BW.
Abstract
Plantevernmidler er et viktig verktøy i dagens plantevernpraksis i jordbruket for å sikre gode avlinger. Miljørisikoen knyttet til det enkelte plantevernmiddel vurderes nøye før det godkjennes for bruk, men langvarig overvåking er nødvendig for å avdekke de faktiske miljøkonsentrasjoner og - effekter etter forskriftsmessig bruk av plantevernmidler. Sveriges nasjonale miljøovervåkingsprogram for plantevernmidler startet i 2002. Hovedmålet med programmet er å følge langtidstrender i påvirkningen av jordbrukets plantevernmiddelbruk på kvaliteten av overflate- og grunnvann, samt å bestemme miljøkonsentrasjonene av plantevernmidler i sediment, luft og nedbør. Formålet med denne evalueringen var å vurdere styrker og svakheter ved overvåkingsprogrammet, samt behov for endringer i den praktiske gjennomføringen, rapporteringsprosedyrer og målsetningen med programmet. Denne evalueringen vurderer også behovene hos de aktuelle sluttbrukergruppene for programmet som inkluderer svensk landbruks- og miljøforvaltning, rådgivningstjenesten i landbruket, bønder og bondeorganisasjoner mv.
Abstract
Pollination sustains biodiversity and food security, but pollinators are threatened by habitat degradation, fragmentation, and loss. We assessed how remaining forest influenced bee visits to flowers in an oil palm-dominated landscape in Borneo. We observed bee visits to six plant species: four crops (Capsicum frutescens L. “chili”; Citrullus lanatus (Thunb.) Matsum & Nakai “watermelon”; Solanum lycopersicum L. “tomato”; and Solanum melongena L. “eggplant”); one native plant Melastoma malabathricum L. “melastome”; and the exotic Turnera subulata Smith “turnera”. We made one local grid-based and one landscape-scale transect-based study spanning 208 and 2130 m from forest, respectively. We recorded 1249 bee visits to 4831 flowers in 1046 ten-min observation periods. Visit frequency varied among plant species, ranging from 0 observed visits to S. lycopersicum to a mean of 0.62 visits per flower per 10 min to C. lanatus. Bee visitation frequency declined with distance from forest in both studies, with expected visitation frequency decreasing by 55% and 66% at the maximum distance from forest in each study. We also tested whether the distance to the nearest oil palm patch, with a maximum distance of 144 m, influenced visitation, but found no such associations. Expected visitation frequency was 70%–77% lower for plants close to a 200 ha forest fragment compared with those near large continuous forests (>400 ha). Our results suggest that, although found throughout the oil palm-dominated landscape, bees depend on remaining forests. Larger forests support more bees, though even a 50 ha fragment has a positive contribution. Abstract in Indonesian is available with online material.
Authors
Tove Aagnes Utsi Nigel Yoccoz Claire Armstrong Victoria Gonzalez Snorre Hagen Ingibjörg Svala Jónsdóttir Nhat Minh Pham Francisco I. Pugnaire Katriona Shea David A. Wardle Sophia Zielosko Kari Anne BråthenAbstract
No abstract has been registered
Abstract
The high Arctic archipelago of Svalbard (74°–81° north) experiences extended periods of uninterrupted daylight in summer and uninterrupted night in winter, apparently relaxing the major driver for the evolution of circadian rhythmicity. Svalbard ptarmigan (Lagopus muta hyperborea) is the only year-round resident terrestrial bird species endemic to the high Arctic and is remarkably adapted to the extreme annual variation in environmental conditions. Here, we demonstrate that, although circadian control of behavior disappears rapidly upon transfer to constant light conditions, consistent with the loss of daily activity patterns observed during the polar summer and polar night, Svalbard ptarmigans nonetheless employ a circadian-based mechanism for photoperiodic timekeeping. First, we show the persistence of rhythmic clock gene expression under constant light within the mediobasal hypothalamus and pars tuberalis, the key tissues in the seasonal neuroendocrine cascade. We then employ a “sliding skeleton photoperiod” protocol, revealing that the driving force behind seasonal biology of the Svalbard ptarmigan is rhythmic sensitivity to light, a feature that depends on a functioning circadian rhythm. Hence, the unusual selective pressures of life in the high Arctic have favored decoupling of the circadian clock from organization of daily activity patterns, while preserving its importance for seasonal synchronization.
Authors
Natalia Fraija-Fernández Andrea Waeschenbach Andrew G. Briscoe Suzanne Hocking Roman Kuchta Tommi Nyman D. Timothy J. LittlewoodAbstract
Broad tapeworms (Diphyllobothriidea) are parasites whose adults are capable of infecting a wide range of freshwater, marine and terrestrial tetrapods including humans. Previous works examining the evolution of habitat and host use in this group have been hampered by the lack of a well-resolved phylogeny. In order to produce a robust phylogenetic framework for diphyllobothriideans, we sequenced the complete mitochondrial genome of 13 representatives, carefully chosen to cover the major clades, and two outgroup species representing the Spathebothriidea and Haplobothriidea. In addition, complementary data from the nuclear ribosomal operon was sequenced for 10 representative taxa. Mitogenomes and ssrDNA and lsrDNA were used towards elucidating the phylogenetic framework for the Diphyllobothriidea. The Cephalochlamydidae is confirmed as the earliest diverging diphyllobothriidean lineage, and Solenophoridae and Diphyllobothriidae are sister groups. We infer a probable freshwater origin of the diphyllobothriideans. The ancestral condition for life cycle complexity could not be unambiguously resolved. However, we infer exclusive use of a three-host life cycle following the origin of the Solenophoridae + Diphyllobothriidae. Regarding definitive host use, although we infer reptiles as the most likely ancestral condition, this result should be revisited with a more densely sampled phylogeny in future studies. Freshwater habitat is used by the early diverging lineages within the Solenophoridae + Diphyllobothriidae clade. For the latter, habitat use shifts between freshwater and marine environments, and definitive host use includes marine and terrestrial mammals and birds. We use mitochondrial genomes to distinguish Schistocephalus species occurring in different species of sticklebacks and demonstrate conspecificity of Ligula cf. intestinalis specimens collected from two Fennoscandian ringed seal subspecies.
Authors
Michal Sposob Radziah Wahid Keno FischerAbstract
Power-to-methane technology is a promising solution to facilitate the use of excess variable renewable energy for biomethane production. In this approach, hydrogen produced via electrolysis is used to upgrade raw biogas, which can be subsequently used as fuel or stored in the gas grid. Ex-situ biomethanation is an emerging technology that could potentially replace conventional energy-intensive biogas upgrading methods and allow CO2 utilization for biomethane production. This work provides a comprehensive overview on the current status of ex-situ biomethanation with particular attention to trickle bed reactor. The review includes description of ex-situ biomethanation and summarizes previous works on this topic. The key elements related to operational conditions, efficiency, and microbiology of ex-situ biomethanation using trickle bed reactor are described here. Additionally, the review highlights the technical and economic issues that have to be addressed for future development and large-scale implementation of ex-situ biomethanation.