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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.

2018

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Abstract

The population structure of cloudberry (Rubus chamaemorus L.), collected from Krkonose Mountains (the Czech Republic), continental Norway and Spitsbergen, was examinedusing microsatellite analyses (SSR). Among 184 individuals, 162 different genotypeswere identified. The overall unbiased gene diversity was high (̂h=0.463). A high level of genetic differentiation among populations (FST = 0.45; p < .01) indicated restricted gene flow between populations. Using a Bayesian approach, six clusters were found which represented the genetic structure of the studied cloudberry populations. The value of correlation index between genetic and geographical distances (r = .44) indicates that gene flow, even over a long distance, could exist. An exact test of population differentiation showed that Rubus chamaemorus populations from regions (Krkonose Mountains,continental Norway and Spitsbergen) are differentiated although some individuals within populations share common alleles even among regions. These results were confirmed by AMOVA, where the highest level of diversity was found within populations(70.8%). There was no difference between 87 pairs of populations (18.7%) mostly within cloudberry populations from continental Norway and from Spitsbergen. Based on obtained results, it is possible to conclude that Czech and Norwegian cloudberry popula-tions are undergoing differentiation, which preserves unique allele compositions most likely from original populations during the last glaciation period. This knowledge will be important for the creation and continuation of in situ and ex situ conservation of cloud-berry populations within these areas.

Abstract

Bilberry (Vaccinium myrtillus L.) is one of the important economical berry species found in the boreal forests of northern latitudes such as Norway and Finland. They are rich in anthocyanins, carotenoids vitamins and other flavonoids that accumulates in skin and flesh of the fruit. Berries from northern latitudes are found to contain more phytochemicals with anti-oxidant capacity than southern clones. It is mainly due to the environmental conditions of northern hemisphere and genetic adaptation that favors higher accumulation of bioactive metabolites such as anthocyanins. The phenylpropanoid pathway is the major key regulatory system for most of the bioactive compounds including anthocyanins which are synthesized via a branch called as flavanoid pathway. Abiotic factors, such as temperature, photoperiodism, light quality & quantity has a major role in biosynthesis and regulation mechanisms. It is usually mediated by MBW complex (R2R3 MYB transcription factors, basic helix-loop-helix and WD 40 repeat proteins). Our studies has been currently focussed on understanding the developmental and environmental regulation of anthocyanin biosynthesis in early to late ripening stages of non-climacteric bilberry fruit in response to different light conditions. The bilberry clones were collected from an island near Tromsø and were subjected to different light conditions such as red, far-red and blue wavelength from Heliospectra lamps during the onset of ripening stages. Simultaneously, the unriped berries were also detached and kept in petri dishes under the lamps to analyze the response of anthocyanin accumulation. Morphological changes in berry skin color were scored from the petri plates. Also, the fruit and leaf tissues were collected from the plants for gene expression analysis of biosynthetic structural genes such as anthocyanin synthase, chalcone synthase and regulatory genes (MBW transcrption factors) at different time points. Our preliminary results has shown that red and blue wavelengths are positively upregulating the anthocyanin accumulation during different developmental stages of bilberry.

Abstract

Wild berries are abundant in phytochemicals that consists primarily of flavonoids, carotenoids and some related polyphenolic compounds that accumulates in skin and flesh of the fruit. These compounds are key contributors for nutritional composition of fruits with anti-oxidant capacity. Anthocyanins, one of the most conspicuous classes of flavonoids together with proanthocyanidins and their derivatives are important plant pigments responsible for the red, pink, purple, and blue colors in plants. The berries from northern latitudes are found to contain more phytochemicals with antioxidant capacity than southern clones. It is mainly due to the environmental conditions of northern hemisphere and genetic adaptation that favors higher accumulation of bioactive metabolites. Phenylpropanoid pathway is the major key regulatory system for most of the bioactive compounds including anthocyanins which itself synthesized via a branch called the flavanoid pathway. Abiotic factors, such as temperature, photoperiodism, light quality & quantity has a major role in biosynthesis and regulation mechanisms. It is usually mediated by MBW complex (R2R3 MYBs, bHLH and WD 40 repeat proteins). The present study is focused on bridging the gap between environmental cues in regulation of the biosynthesis in two non-climacteric berry species, wild bilberry (Vaccinium myrtillus) and woodland strawberry (Fragaria vesca) with response to different light conditions. Our preliminary results has shown that red and blue wavelengths are positively upregulating the anthocyanin accumulation during early to late ripening stages of bilberry. Active participation in this Nordplant kickoff meeting will help me to promote my research work and get feedbacks and suggestions among my fellow plant researchers from Nordic countries and partner institutions. It can also help me to improve my knowledge on high throughput phenotyping techniques from the talks and by visiting the cutting edge facilities and infrastructures at University of Helsinki, which can also be applied in this PhD project at later stages.

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Abstract

The aim of the investigation was to assess and compare the environmental limits for growth cessation and floralinitiation in a range of new and established biennial-fruiting red raspberry (Rubus idaeus L.) cultivars of diverseorigin under phytotron and field conditions. The results confirmed that growth cessation and floral initiation inbiennial-fruiting red raspberry are jointly controlled by the interaction of low temperature and short days (SD).When transferred from non-inductive high temperature and long day (LD) conditions to naturally decreasingautumn daylengths at varying phytotron temperatures on 18 August, growth immediately levelled off and ceasedcompletely within 2 weeks in all cultivars at 9 °C. Serial dissections of lateral buds revealed that floral initiationsimultaneously took place. At 15 °C on the other hand, the plants continued growing and remained vegetativeuntil around 15 September when the daylength had decreased to approximately 13 h. The change to 9 °C resultedin an immediate but short-lasting floral induction response that did not bring about initiation in buds situatednear the base of the canes, as was the case at 15 °C. At 18 °C, marginal floral induction took place only in thecultivars ‘Glen Ample’, ‘Balder’ and ‘Vene’, even at photoperiods down to 10 h, whereas at 21 °C, all cultivarsgrew vegetatively regardless of daylength conditions. However, exceptions were some plants of ‘Vene’ and‘Anitra’ that initiated terminal flowers at 18 and 21 °C and flowered directly without chilling (so-called tipflowering). Although some cultivars of Northern origin ceased growing and initiated floral primordia somewhatearlier (at longer photoperiods) than those of more southerly origin, the differences were relatively minor andnot consistent (no latitudinal cline). Results obtained in the field under decreasing autumn temperature anddaylength conditions agreed closely with the results in the phytotron. We therefore conclude that results ob-tained with raspberry in properly controlled daylight phytotron experiments are generally applicable to fieldconditions.

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Abstract

Effects of annual versus biennial cropping with varying shoot densities on plant structure, berry yield and quality were studied in ‘Glen Ample’ raspberry over a period of four seasons (two cropping years). In the vegetative phase, primocane height and internode length were larger in the annual than in the biennial cropping system. These parameters as well as Botrytis infestation increased with increasing shoot density. In both cropping years, berry yields per unit area were about 20% higher in the biennial cropping system, whereas yields per shoot were not significantly different in the two systems. In both cropping systems, yields per shoot strongly declined with increasing shoot density, while yields per metre row increased slightly. Regardless of cropping system, yields per metre row did not increase with increasing shoot density beyond eight shoots per metre. The concentrations of dry matter, soluble solids, titratable acidity and ascorbic acid as well as the intensity of juice colour all declined with increasing shoot density. We conclude that under controlled shoot density conditions, there is little scope for biennial yield increases that fully compensates for the lost crops every second year. However, the system greatly facilitates berry harvest and eases plant disease pressure.