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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.

2017

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Sammendrag

Different sowing methods and sowing rates were evaluated in organic seed production of timothy (two trials), meadow fescue (two trials) and red clover (one trial) in Southeast Norway, during 2010–2013. The plan included: (1) broadcast sowing of grass/clover, cover crop sown at 12 cm row distance; (2) sowing of cover and seed crop in crossed rows, both at 12 cm row distance; and (3) sowing of cover crop and seed crop in every other row. The three sowing rates were 5, 10 and 15 kg ha−1 in timothy and meadow fescue and 3, 6 and 9 kg ha−1 in red clover. On average for sowing rates and all trials with timothy, meadow fescue and red clover, first year’s seed yields were 5–6%, 20–25% and 19–25% higher on plots sown with cover crop and seed crop in every other row than on plots where seed crop had been broadcast or sown perpendicularly to the cover crop. The different sowing methods had no effect on weed coverage or weed contamination in the cleaned seed. Increasing sowing rate usually had a negative influence on seed yield, while weed coverage/contamination was not significantly affected. It is concluded that organic seed crops should be established with cover crop and seed crop in every other row at a low sowing rate. However, in an organic production system, even this favorable method will not always be sufficient to meet the requirement for seed crop purity.

Sammendrag

Western livestock sectors have shifted towards fewer, larger farms, causing concerns about the appearance of the countryside, ecosystem services, and rural depopulation. This study empirically estimates factors likely to affect exit intentions in sheep farms. Data were collected from specialised sheep farms included in the Norwegian Farm Business Survey. Of the 59 responses, 44 operators believed the farm would be producing sheep in 10 years. A logistic regression model was used to determine the most decisive variables associated with an exit intention, where the interdependence of factors affecting profitability and, subsequently, exit intention were taken into account. This study found that farmers reporting the most positive views of the local farming community were less likely to plan an exit. Exit intentions were not significantly influenced by farming goals, location, off-farm income, or profitability. The primacy of non-economic, community-based factors as an engine to sustain farms, suggests that more attention need to be paid to social processes and relations in local communities. Farmer groups and policy-makers should consider how to encourage supportive local communities when designing policies to retain sheep farms.

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• Vernalisation requirement is an agriculturally important trait that postpones the development of cold-sensitive floral organs until the spring. The family Rosaceae includes many agriculturally important fruit and berry crops that suffer from crop losses caused by frost injury to overwintering flower buds. Recently, a vernalisation-requiring accession of the Rosaceae model woodland strawberry (Fragaria vesca) has been identified in northern Norway. Understanding the molecular basis of the vernalisation requirement in this accession would advance the development of strawberry cultivars better adapted to temperate climate. • We use gene silencing, gene expression analysis, genetic mapping and population genomics to study the genetic basis of the vernalisation requirement in woodland strawberry. • Our results indicate that the woodland strawberry vernalisation requirement is endemic to northern Norwegian population, and mapping data suggest the orthologue of TERMINAL FLOWER1 (FvTFL1) as the causal floral repressor. We demonstrate that exceptionally low temperatures are needed to downregulate FvTFL1 and to make these plants competent to induce flowering at low postvernalisation temperatures in the spring. • We show that altered regulation of FvTFL1 in the northern Norwegian woodland strawberry accession postpones flower induction until the spring, allowing plants to avoid winter injuries of flower buds that commonly occur in temperate regions.

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BACKGROUND: It is questioned if Norwegian nurseries can compete with the continental nursery industry in an open market. OBJECTIVE: Investigated how quality of certified Norwegian strawberry transplants, developed and yielded from planting to first cropping year. METHODS: Plant qualities of Norwegian fresh and cold stored bare root- and plug-plants of ‘Korona’ and ‘Sonata’ were examined for establishing and yield parameters in the open, after three intervals of planting. Fresh plug-plants were delivered when available. Trials were established at NIBIO Research Station Kvithamar, Norway. Growth and yield parameters were registered in the establishing and cropping years. RESULTS: Plant establishment was poor in 2013 compared with 2014. Bare-root plants stored at 2–4°C generally developed poorly. Plug-plants established well at all delivery dates, except fresh plug in one year. Development of runner plants depended on plant type, cultivar and year. Plug- and bare root-plants planted immediately after first delivery generally developed best crowns. Primary flower primordia reached a more developed stage for ‘Sonata’ than for ‘Korona’. Fruit yield of bare root was low in the establishing years. Plant-types differed in yield and fruit weight between cropping years. CONCLUSIONS: Bare-root and plug- plants planted one day after delivery generally yielded best. Storage of bare-root plants generally reduced yield. Fresh plug plants had low yield when planted late. Fruit yield of A15 and A13 in the establishing year was not satisfactory.

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Sammendrag

Plants of six strawberry cultivars were raised under controlled conditions and tested for flowering and yield potential. Short days (SD) at intermediate temperatures for 4 weeks in August induced profuse flowering in subsequent long days (LD) in all cultivars except the late-flowering ‘Malwina’. LD conditions induced flowering only in ‘Nobel’, which has an everbearing parent. ‘Nobel’ and ‘Saga’ exhibited broad temperature adaptation for SD floral induction, which was generally reduced or suppressed at 9 and 27°C. After autumn planting, all cultivars flowered most abundantly in plants raised in SD and intermediate temperatures. Flowering was earliest in ‘Nobel’ and ‘Rumba’. Plants that did not reach floral commitment after 4 weeks in SD continued and completed induction under subsequent natural SD conditions after planting in the field, demonstrating the capability of fractional induction. Berry yield varied in parallel with flowering in the field and was always higher in plants raised under SD conditions. The traditional cultivars ‘Florence’ and ‘Sonata’ out-yielded the more recent cultivars. Some cultivars lost more than two thirds of their initiated flowers during the winter with obvious consequences for their yields. With proper raising management, acceptable yields were obtained after autumn planting even in a cool Nordic climate.