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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.

2009

Abstract

Wild berries are a characteristic part of Northern nature and a particular speciality of Nordic countries. Wild berries are also a rich and valuable resource that has not yet been exploited in a satisfactory level. Approximately 90 – 95 % of the whole wild berry crop yield is left unpicked in the Nordic forests every year. The challenges of wild berry utilization are similar in Nordic countries - the logistics of berry picking including traceability, fragmented sector structure as well as the high share of unprocessed raw material in export. The Nordic project focusing on bilberry (Vaccinium myrtillus) “Bilberry: Towards functional food markets” (2007 – 2009) is a part of the New Nordic Food programme funded by the Nordic Innovation Centre. The programme aims to enhance cooperation and innovation among companies that utilize the natural resources of the Nordic countries. The aim of the project is to improve wild berry production and utilization in the Nordic and global market. To achieve this goal a network between the Nordic experts presenting the different fields of the wild berry sector has been established. The project has focused on marketing research, quality issues, biodiversity and the traceability of wild berries; especially the bilberry. The results of the marketing survey were published in November 2008. The aim of the survey was to generate an overall picture of the companies working with wild berries in Nordic countries and to gather information on the existence and willingness of the berry companies to cooperate in wild berry supply, logistics, marketing and research and development. According to the results, a general agreement for the need of increased cooperation at the Nordic level was highlighted.

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Abstract

Yields are reported from four long-term (16 30 years) tillage trials, comparing results since 1998, under relatively wet conditions, with earlier experience. In trial 1, on clay loam, mean grain yield with spring harrowing only, has since 1998 been 87% of that obtained with autumn ploughing, whereas it was 94% for the whole period since 1991. The inclusion of autumn harrowing increased these figures to 94 and 98%, respectively. Over the last six years, spring ploughing gave 5% lower yield than did autumn ploughing. Relative yields of unploughed versus ploughed treatments were negatively correlated with summer rainfall. Grain protein was lowest with spring harrowing only. In trial 2, on clay loam, direct drilling has since 1998, as in previous years, given around 10% lower yield than has autumn ploughing. Autumn harrowing gave 4% lower yield in winter wheat and 6% higher yield in spring oats than did autumn ploughing, whilst yields of spring turnip rape were not significantly affected by tillage. In trial 3, also on clay loam, six alternative straw treatments were compared under four unploughed tillage regimes. Relative to straw removal, retaining large residue amounts depressed yields hardly at all with autumn and spring harrowing, but by 7% with spring harrowing only and by 13% with direct drilling. Overall, direct drilling gave 18% lower yields in this trial than did autumn and spring harrowing, whilst the yield reduction with spring harrowing only was 7%. In trial 4, on silt loam, both spring harrowing only and direct drilling have since 1998 given 6% lower yield than has autumn ploughing, whereas autumn and spring harrowing has given 6% higher yield. Under drier conditions during 1991 1997, autumn ploughing gave up to 11% lower yield than did unploughed treatments. Straw retention was beneficial in the absence of ploughing during that period, but has had little effect in more recent years.

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Abstract

Growth and flowering of the annual-fruiting raspberry (Rubus idaeus L.) cultivar 'Polka' were studied under controlled environment conditions in order to facilitate out-of-season production. Vegetatively-propagated plants originating from adventitious root buds were used. Height growth and the rate of leaf formation increased with increasing temperature, up to a broad optimum in the mid-20 degrees C range. While elongation was consistently enhanced by long-day (LD) conditions, photoperiod had no effect on the rate of leaf formation. LD stimulation of growth thus resulted from increased internode length only. In agreement with earlier reports, it was found that, in contrast to biennial-fruiting cultivars, such annual-fruiting cultivars do not need low temperatures for flower initiation, nor do they appear to have a juvenile phase during which they are un-responsive to flower-inducing conditions. 'Polka' plants responded to inductive conditions as early as the 5-leaf stage, and flowered freely across the entire range of growth temperatures, even at 30 degrees C. Flowering was advanced and the number of flowers increased with increasing temperature, up to an optimum at 27 degrees C. Flowering was also consistently advanced and occurred at lower nodes under LD than under short-day (SD) conditions across the whole range of temperatures. Night interruption for 3 h in the middle of the night was also effective, demonstrating that this is a true photoperiodic response and not merely an effect of increased light integral in LD. It was also confirmed that a distinct vernalisation-type advancement of flowering took place when small, non-dormant plants were exposed to additional chilling at 6 degrees C for several weeks. At low temperatures, a large proportion of the lateral buds were dormant, so that, at 12 degrees C, the plants actually flowered only at their tips. Dissections also revealed that the dormant buds had initiated flowers; but, because of their dormant state, they needed several weeks of chilling before they could flower (biennial-fruiting behaviour). Both types of buds were initiated by the same environmental conditions. Practical applications of the findings are suggested.

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Abstract

Environmental control of flowering and runnering in three contrasting Fragaria chiloensis populations with geographic origins in Alaska, Oregon, and Chile have been studied under controlled environment conditions. All populations were principal short-day (SD) plants at intermediate temperatures (15 degrees C or 21 degrees C), while at low temperature (9 degrees C) the 'Alaska' and 'Chile' populations were essentially day neutral. However, the populations had contrasting temperature responses for flowering in SD at both constant and fluctuating day/night temperatures. At a day temperature of 18 degrees C, flowering increased with increasing night temperature from 9 degrees C to 21 degrees C in the 'Alaska' population, while the opposite trend was observed in the 'Chile' population. The sparsely flowering 'Oregon' population flowered only in SD within a narrow range of temperatures (15-18 degrees C). Photoperiod (10, 16, or 20 h) had no effect on flower development at 18 degrees C. All populations were runnering freely, but with different temperature and photoperiod modifications. It is concluded that the SD X temperature interaction in the flowering behaviour of the June-bearing cultivated strawberry, F. X ananassa, is inherited to a large extent from F. chiloensis, whereas the species does not appear to have contributed to the long-day (LD) flowering control in everbearing cultivars.

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Abstract

The effects of timing of nitrogen (N) fertilization relative to the beginning of a 4-week floral-inducing short-clay (SD) period have been studied in 'Korona' strawberry plants under controlled environment conditions. Groups Of low fertility plants were fertilized with 100 ml of calcium nitrate solution for 3 days a week for a period of 3 weeks starting at various times before and at the beginning of the SD period, as well as at different times during the SD period. All plants, including SD and long day (LD) control plants, received a weekly fertilization with a low concentration complete fertilizer Solution throughout the experiment. Leaf at-ea. fresh and dry matter increments of leaves, crowns and roots, as well as leaf chlorophyll concentration (SPAD Values) were monitored during the experimental period. A general enhancement of growth took place at all times of N fertilization. This was paralleled by an increase in leaf chlorophyll concentration, indicating that the control plants were in a mild state of N deficiency. When N fertilization was started 2 weeks before beginning of the SD period, flowering was delayed by 7 days, and this was gradually changed to an advancement of 8 days when the same treatment was started 3 weeks after the first SD. The amount of flowering was generally increased by N fertilization although the effect varied greatly with the time of N application. The greatest flowering enhancement Occurred when N fertilization started I week after the first SD when the number of flowering crowns and the number of inflorescences per plant were more than doubled compared with the SD control, while fertilization 2 weeks before SD had no significant effect on these parameters. Importantly, the total number of crowns per plant was not affected by N fertilization at any time, indicating that enhancement of flowering was not due to an increase in potential inflorescence sites. No flowering took place in the control plants in LD. Possible physiological mechanisms involved and practical applications of the findings are discussed. (C) 2009 Elsevier B.V. All rights reserved.