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Conthey, Switzerland

Carlen C.,Conthey Research Station | Carron C.-A.,Conthey Research Station | Simonnet X.,Mediplant
Acta Horticulturae | Year: 2012

This paper presents a review on the cultivation of white genepi (Artemisia umbelliformis), a plant mainly used in liquor production for the aromatic and bitter compounds found in the floral stems, and points out two very important aspects: harvest stage and environmental conditions. In previous studies, the incidence of the phenological stage at harvest on the yield and the quality of the floral stems of white genepi cultivar 'RAC 12' was very high. The yield doubled between the beginning and the end of the flowering period, reaching up to 0.1 kg of dry weight per m2. Harvesting from full flowering onwards resulted in higher yields. On the contrary, the contents of essential oil and of costunolide in the flower stems drastically decreased between the beginning and the end of flowering. However, no significant variation in the chemical profile of the essential oil was observed in relation to the harvesting stages. Harvesting of white genepi at the beginning of flowering is therefore recommended to guarantee a high quality product. The optimal environment to cultivate genepi is on sandy soils (>60% sand of the soil texture) and at high altitudes (1200-1600 m in middle Europe). On sandy soils, the plant mortality turned out to be lower, and consequently the yields were higher compared to soils with a high percentage of clay and silt. High altitudes are therefore recommended, mainly because of increasing the yield and the profitableness of the crop. © WIETE 2012. Source


Michel V.V.,Agroscope | Debrunner N.,Mediplant | Simonnet X.,Mediplant
HortScience | Year: 2014

Anthracnose is a major production constraint for st. john's wort (Hypericum perforatum L.) caused by the fungus Colletotrichum gloeosporioides (Penz.). A greenhouse screening method based on mortality was developed to eliminate accessions susceptible to anthracnose in the early stage of breeding for resistant cultivars. The mortality of 22 accessions of st. john's wort artificially inoculated with a strain of C. gloeosporioides was highly correlated between three greenhouse experiments (r = 0.799 to 0.923), even when done at two different places. The response of the greenhouse screening was equally highly correlated to the mortality in the field tested at two sites naturally infested with C. gloeosporioides (r = 0.700 to 0.865) but less well correlated with the mortality at a third field site (r = 0.495 to 0.672). Yield of st. john's wort was highly correlated with mortality (r = -0.747 to -0.846) at all three field sites, but a significant interaction between accession and site was observed. Therefore, an improvement of anthracnose resistance of st. john's wort should be based on a greenhouse screening of seedlings followed by multiple-site field testing of adult plants. Source


Camps C.,Agroscope Liebefeld Posieux Research Station | Gerard M.,Agroscope Liebefeld Posieux Research Station | Quennoz M.,Mediplant | Brabant C.,Agroscope Liebefeld Posieux Research Station | And 2 more authors.
Journal of the Science of Food and Agriculture | Year: 2014

BACKGROUND: In the framework of a breeding programme, the analysis of hundreds of oregano samples to determine their essential oil content (EOC) is time-consuming and expensive in terms of labour. Therefore developing a new method that is rapid, accurate and less expensive to use would be an asset to breeders. The aim of the present study was to develop a method based on near-inrared (NIR) spectroscopy to determine the EOC of oregano dried powder. Two spectroscopic approaches were compared, the first using a hand-held NIR device and the second a Fourier transform (FT) NIR spectrometer. RESULTS: Hand-held NIR (1000-1800 nm) measurements and partial least squares regression allowed the determination of EOC with R2 and SEP values of 0.58 and 0.81 mL per 100 g dry matter (DM) respectively. Measurements with FT-NIR (1000-2500 nm) allowed the determination of EOC with R2 and SEP values of 0.91 and 0.68 mL per 100 g DM respectively. RPD, RER and RPIQ values for the model implemented with FT-NIR data were satisfactory for screening application, while those obtained with hand-held NIR data were below the level required to consider the model as enough accurate for screening application. CONCLUSION: The FT-NIR approach allowed the development of an accurate model for EOC prediction. Although the hand-held NIR approach is promising, it needs additional development before it can be used in practice. © 2013 Society of Chemical Industry. Source


Camps C.,Research Center Conthey | Toussirot M.,Research Center Conthey | Quennoz M.,Mediplant | Simonnetb X.,Mediplant
Journal of Near Infrared Spectroscopy | Year: 2011

A rapid, low-cost method, based on near-infrared spectroscopy (NIR), was developed to determine artemisinin and moisture content in dry powder of Artemisia annua (A. annua) leaves. A calibration set of 60 samples and validation set of 40 samples of A. annua hybrids exhibiting artemisinin content of between 0.7% and 1.6% was used. Results of partial least squares modelling indicated that NIR was accurate in predicting artemisinin content. Root mean square error values of cross-validation (RMSECV) and prediction (RMSEV) of 0.1% were calculated, in both cases. A model of moisture content was particularly accurate with RMSECV and RMSEP values of 0.8% (R = 0.99) and 1.4%, respectively. © 2011 IM Publications LLP. All right reserved. Source


Quennoz M.,Mediplant | Bastian C.,University of Applied Sciences and Arts Western Switzerland | Simonnet X.,Mediplant | Grogg A.F.,University of Applied Sciences and Arts Western Switzerland
Chimia | Year: 2010

Artemisinin is a natural molecule highly active against malaria. At present, the extraction of this molecule from the leaves of Artemisia annua L. remains the only viable method to produce cheaply large quantities of artemisinin. Agronomic research on this plant species aims to improve agricultural yields, to decrease production costs and to ensure a steady global supply of artemisinin. These research activities require an easy, rapid, low cost, and reliable analytical technique to quantify the artemisinin content in the leaves. Thin layer chromatography (TLC) methods to quantify this molecule have already been published. However, this method does not allow the quantification of the total artemisinin content in the leaves. In order to validate the TLC method, results obtained with this method were related to results for the same samples obtained by accelerated solvent extraction and high pressure liquid chromatography with an evaporative light scattering detector (ASE-HPLC-ELSD). Using the Nernst partition law, a corrective factor of 1.21 is suggested to enable information about the true total amount of artemisinin in leaf samples to be obtained within a range of 0.25 to 3%. In conclusion, this study proposes for the first time a corrective factor in order to quantify the total artemisinin content of A. annua leaves with TLC. Source

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