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.
2008
Sammendrag
Tannin-enriched extracts from raspberry, cloudberry and strawberry were analysed by liquid chromatography"mass spectrometric (LC"MS) techniques. The raspberry and cloudberry extracts contained a similar mixture of identifiable ellagitannin components and ellagic acid. However, the strawberry extract contained a complex mixture of ellagitannin and proanthocyanidin components that could not be adequately resolved to allow identification of individual peaks. Nevertheless, the negative ESI-MS spectra obtained by direct infusion mass spectrometric (DIMS) analysis described the diversity of these samples. For example, the predominance of signals associated with Lambertianin C in cloudberry and Sanguiin H6 in raspberry tannin extracts could be discerned and the diversity of signals from procyanidin and propelargonidin oligomers could be identified in the strawberry extract. The dose response for the main ellagitannin-derived signals in the raspberry tannin sample revealed a saturation effect probably due to ion suppression effects in the ion trap spectrometer. Nevertheless, DIMS spectra of whole berry extracts described qualitative differences in ellagitannin-derived peaks in raspberry, cloudberry and strawberry samples. In addition, positive mode DIMS spectra illustrated qualitative differences in the anthocyanin composition of berries of progeny from a raspberry breeding population that had been previously analysed by LC"MS. This suggests that DIMS could be applied to rapidly assess differences in polyphenol content, especially in large sample sets such as the progeny from breeding programmes.
Sammendrag
Commercial strawberry production in Scandinavia started as early as the 1920s, with the cultivar `Abundance". Although the production area was about 1500 ha, the yield was very low (< 3 t ha-1). In the 1960s Scandinavia had a large increase in strawberry area and yield per hectare. The strong development of strawberry production came after the introduction of the cultivar `Senga Sengana", new growing techniques (black polyethylene mulch) and the release of new and more efficient fungi- and herbicides. Over the past 30 years, the yield and growing area has stabilized, although the number of strawberry growers has decreased strongly. Today, Scandinavia has a strawberry production of about 8500 ha, yielding about 75 000 tons of berries in a very short summer-season. Almost all strawberry growing is perennial production with single-cropping (SD) cultivars in open field, and the fields are normally kept for 3-5 years. The main strawberry cultivars grown today are `Korona", `Polka", `Honeoye", `Jonsok" and `Florence". The area of `Sonata" is increasing. While almost all strawberries up to the 1970s were picked and sold through a "pick-your-own" system, today, almost 95% is sold through wholesale dealers for fresh consumption, and only a small amount is frozen for processing. Since the mid 1990s, there has been a slow decrease in the strawberry production area in Scandinavia. This is due to an over-production of strawberries in a short, hectic season, giving very low prices. To avoid this, attempts are being made to extend the season, especially with row cover, plastic tunnels, stored plants and new cultivars (including everbearing cvs.). The growing area covered with polyethylene tunnels are now increasing in all the Scandinavian countries. The area of raspberry in Scandinavia was stable up to the 1990s, with a production of about 500 ha. The production was mainly for the processing industry with old Norwegian and Finnish cultivars. Since 1995, the raspberry area has doubled, and is still increasing. This came after introduction of the Scottish cultivar `Glen Ample", which has shifted the production from mainly for the processing industry, over to mainly for fresh consumption. This development was started in Norway, and the other Scandinavian countries are following up. Introduction of `Glen Ample" has given the growers new possibilities to increase their income, and the focus on extending the season and on berry quality, have increased. About half of the Norwegian raspberry production is now under polyethylene tunnels, and this leads again to new possibilities of extension of the season by growing long canes or primocane-fruiting varieties like `Polka". Less than 120 ha of blueberries are produced in Scandinavia. The yields are low, and the picking cost too high. But, there is increasing interest, related to health benefits, from the marked. The main challenges for berry production in Scandinavia are access to and cost of labour, and how to meet the increased competition from imported berries. The Scandinavian countries have also strong restrictions in the number, and use of pesticides. Increased focus on taste and quality will be important in the future.
Sammendrag
Environmental control of the annual growth cycle of 'Glen Ample' raspberry has been studied in order to facilitate crop manipulation for out-of-season production. Plants propagated from root buds were raised in long days (LD) at 21 degrees C and then exposed to different temperature and daylength conditions at varying ages. Shoot growth was monitored by weekly measurements and floral initiation by regular sampling and examination of axillary bud #5. Under natural summer daylight conditions at 60 degrees N shoot growth was nearly doubled at 21 degrees C compared with 15 degrees C, while at 9 degrees C one half of the plants ceased growing and formed flower buds at midsummer. Developing shoots have a juvenile phase and could not be induced to flower before the 15-leaf stage. No significant reduction in induction requirements was found in larger plants. Plants exposed to natural light conditions from 10th August, had an immediate growth suppression at 9 and 12 degrees C with complete cessation after 4 weeks (by September 7). This coincided with the first appearance of floral primordia. At 15 degrees C both growth cessation and floral initiation occurred 2 weeks later (by September 21), while at 18 degrees C continuous growth with no floral initiation was maintained until early November when the photoperiod had fallen below 9 h. The critical photoperiod for growth cessation and floral initiation at 15 degrees C was 15 h. Plants exposed to 10-h photoperiods at 9 degrees C for 2-4 weeks had a transient growth suppression followed by resumed growth under subsequent high temperature and LD conditions, while exposure for 5 or 6 weeks resulted in complete growth cessation and dormancy induction. The critical induction period for floral initiation was 3 weeks although no transitional changes were visible in the bud before week 4. When exposed to inductive conditions for marginal periods of 3 or 4 weeks, an increasing proportion of the plants (20% and 67%, respectively), behaved as primocane flowering cultivars with recurrent growth and terminal flowering. It is concluded that growth cessation and floral initiation in raspberry are jointly controlled by low temperature and short day conditions and coincide in time as parallel outputs from the same internal induction mechanism. (C) 2008 Elsevier B.V. All rights reserved.
Sammendrag
Etter sine dyrkingsmessige egenskaper blir våre dyrkete hagejordbær inndelt i engangsbærende og flergangsbærende (remonterende) sorter. Mens blomstringen hos de vanlige engangsbærende sortene har vært gjenstand for omfattende undersøkelser og er kjent for å være indusert av kort dag (KD), har det vært betydelig forvirring i litteraturen om daglengde-reaksjonen for de flergangsblomstrende sortene. I et nylig avslutta forskningsprosjekt har vi imidlertid kunnet fastslå at danningen av blomsterknopper hos disse sortene er indusert av langdags (LD)-forhold. Ved høy temperatur (> 25 ºC) er disse plantene obligatoriske LD-planter, mens de ved midlere temperaturer (15 - 20 ºC) også vil blomstre under KD-forhold, men da er blomstringen sterkt forsinket. Ved lave temperaturer (< 10 ºC) er imidlertid også disse sortene dagnøytrale i likhet med flere av de engangsbærende sortene.
Sammendrag
A field fertilizer trial planted in late August was used to study effects of fertilizer timing and application method on flowering and ripening in strawberry cv. Korona. In treatment 1 (T1), fertilization in August prior to planting was followed by fertigation with low nutrient rate from May to August in the first harvest year. In treatment 2 (T2) all nutrients were applied as nutrient solution from May to August the first harvest year. By August in the first harvest year, the total amount of fertilizer applied was similar for both treatments (80 kg N ha(-1)). Equal amounts of water were also applied in both treatments. In the second harvest year, all the fertilizer was applied using fertigation from May to August. Both treatments were given the same fertilizer rate (80 kg N ha(-1)) to study after-effects of T1 and T2. In the first harvest year, preplant fertilized plants flowered earlier and required a higher number of days and day-degrees from anthesis to berry ripening than did T2 plants which were not fertilized until spring the first harvest year. Significant differences were found in yield but not in the number of berries, as berry size was significantly higher in T1. No significant differences were found between fertilizer treatments in the second harvest year, although T2 tended to yield the maximum number of berries later in the season than T1.
Sammendrag
The environmental control of flowering in five populations of Fragaria virginiana ssp. glauca and three populations of F virginiana ssp. virginiana (henceforth referred to as F virginiana), obtained as seed from the National Plant Germplasm Repository, Corvallis, OR, USA, has been studied under controlled environment conditions. Except for the F virginiana ssp. glauca population PI 551648 from the Wasatch Mountains in Utah, which was truly day-neutral across a 9 degrees - 27 degrees C temperature range, all the other populations of both sub-species behaved as quantitative (facultative) short-day (SD) plants with earlier and more abundant flowering under SD than under long-day (LD) conditions. Flowering of the remaining F virginiana ssp. glauca populations was governed by a significant interaction of photoperiod and temperature. The SD dependence for flowering increased with increasing temperature from 9 degrees C to 27 degrees C. The optimum temperature for the SD flowering response was 15 degrees - 21 degrees C. While SD promotion of flowering was more pronounced in the F virginiana populations, temperature had no significant main effect on flowering in this sub-species, demonstrating a wide temperature tolerance for flowering. Vigorous runner formation was observed in all populations, in both SD and LD, with a highly significant advancement effect of increasing temperature. The flowering and runnering responses of these E virginiana populations are discussed in relation to their putative paternity of perpetual-flowering F. X ananassa cultivars. It is concluded that, with the complex inheritance in these octoploid plants, the flowering responses of the populations studied here are not reflected in the LD flowering response of cultivated everbearing strawberries.
Sammendrag
Det er en vanlig oppfatning blant dyrkere at relativt låg temperatur er gunstig for rik blomsterdanning hos jordbær. I ei tid med klimaendring, er det derfor mange som spør om hvordan de milde høstene vi har hatt i det siste, påvirker blomstring og avling. Samtidig er det mange som har erfart at en sein jordbærsort som "Florence" har gitt små avlinger i nord og i høgtliggende områder med tidlig og kjølig høst. Vi har derfor studert virkningen av ulike temperaturer på blomsterdanningen hos sortene "Florence", "Frida" og "Korona" under kontrollerte klimaforhold og jamført dette med avlingstall fra forsøk med de samme sortene i distrikt med ulike temperaturforhold. Resultata viser at optimal temperatur for kortdags-indusert blomsterdanning er så høg som 18 °C, og at sortsforskjeller i avling i ulike distrikt for en stor del kan forklares ut fra forskjeller i høst-temperaturen.
Sammendrag
The environmental control of flowering in the perpetual-flowering (everbearing) diploid strawberry Fragaria vesca ssp. semperflorens cultivars 'Rugen' and 'Baron Solemacher' has been studied in controlled environments. Seed-propagated plants were exposed to 10-h short-day (SD) and 24-h long-day (LD) conditions at temperatures ranging from 9 degrees - 27 degrees C. The results revealed a quantitative LD response of flowering that increased in strength with increasing temperature, to become almost obligatory at 27 degrees C. Occasional runner formation was observed in SD at high temperature, conditions which were inhibitory to flowering, demonstrating that runnering ability is not completely lost in these genotypes. A comparison with the perpetual-flowering octoploid F X ananassa 'Elan', in one experiment, demonstrated an identical LD X temperature interaction in the two species. The results are discussed in relation to available information on the genetics of flowering habits in the two species. Since seasonal flowering types of F vesca and E X ananassa have also been shown to share a principally identical flowering response, controlled by SD and low temperature, it is concluded that a remarkably similar flowering control system is present in the diploid F vesca and the octoploid F. X ananassa. Despite the large genetic differences between the two species, and regardless of the origin of the cultivars, the seasonal flowering types are all SD plants, while their perpetual-flowering counterparts all appear to be LD plants. In both cases, there is a pronounced interaction with temperature; the photoperiodic responses increasing with increasing temperature, in both cases. This raises the question whether a common genetic flowering control system is present in both species.
Sammendrag
Remonterende jordbærsorter er langdagsplanter, og er dermed svært godt tilpasset våre lange, lyse sommerdager. Sortene har stort avlingspotensiale og bærer gjennom en lang sesong. I et sortsforsøk ved Bioforsk Kise i 2006 og 2007, ble sju remonterende sorter sammenlignet med Korona. I 2007 ble det høstet mer enn 800 gram pr. plante for den beste sorten etter høsting fra 18. juni til 15. oktober. Vi trenger imidlertid bedre remonterende sorter før disse vil få sitt store gjennombrudd hos oss.
Sammendrag
The effect of night temperature on short day (SD) floral induction has been studied in three June-bearing strawberry cultivars of different geographic origin and compared with yield performance in the cool Nordic environment. At the optimum day temperature of 18 degrees C, the SD flowering response of the cultivars 'Florence' and 'Korona' increased significantly with increasing night temperature from 9 to 18 degrees C, while an optimum was reached at 15 degrees C in the cultivar 'Frida' that is selected under cool-environment conditions in Norway. Also, while saturated flowering response was obtained with 3 weeks of SD treatment at all temperatures in 'Frida', several plants of 'Florence' and 'Korona' failed to initiate flowers at 9 degrees C night temperature even with 5 weeks of SD. The effect of extended SD period was particularly pronounced in 'Florence'. The slow SD floral induction response of 'Florence' was associated with a 2 week delay of anthesis in subsequent long day (LD) conditions at 21 degrees C. Yield performance of the same cultivars during 2 years under field conditions at Nes Hedmark and in North Norway also demonstrated that the yield potential of 'Florence' was not realized under the climatic conditions prevailing at these locations. In both years the yields varied significantly among the cultivars,'Frida' having the highest yields followed by 'Korona', with 'Florence' far below. It is concluded that, in the Nordic environment, autumn (September) night temperatures are obviously suboptimal for yield performance of some June-bearing strawberry cultivars, and that this effect is mediated by autumn temperature effects on flower initiation responses. (C) 2008 Elsevier B.V. All rights reserved.