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Kuntzmann P.,Institute Francais Of La Vigne Et Du Vin Ifv | Villaume S.,Conseil Interprofessionnel des Vins dAlsace | Larignon P.,Institute Francais Of La Vigne Et Du Vin Ifv | Bertsch C.,CNRS Vine Biotechnology and Environment Laboratory
Vitis - Journal of Grapevine Research

The French vineyard is affected by three principal wood diseases: Eutypa dieback, esca and black dead arm (BDA). Phaeomoniella chlamydospora, Phaeocremonium aleophilum, Eutypa lata, Fomitiporia mediterranea, Diplodia seriata, Diplodia mutila and Neofusicoccum parvum are the main fungi isolated in France and associated with grapevine trunk diseases. The aim of this study was to highlight the type of wood lesions and the fungus present in the Alsace vineyards (France) and to compare it with those identified in the other french vine-growing regions or with the German vineyards. Therefore, we have studied two vineyards with two different grapevine varieties ('Auxerrois', 'Gewürztraminer'). The foliar symptoms showed that the plots planted with 'Auxerrois' and 'Gewürztraminer' varieties had respectively 12 and 21 % grapevines with symptoms in 2005. Different cross sections were made on trunks and arms of 55 vines showing foliar symptoms, totalizing 162 microbiological isolations. Visual characterisations of the different lesions were described. The isolations made from the different necrosis showed the presence of species of fungi involved in grapevine trunk diseases and other fungi. Microbiological observations showed that for the Auxerrois vineyard the majority of the vines were infected with D. seriata, P. chlamydospora, E. lata and F. mediterranea. In the Gewürztraminer vineyard, the fungus most frequently isolated was P. chlamydospora, followed by D. seriata. The presence of D. seriata in different parts of the grapevine wood and in young wood is related to the severe damages observed on the vegetation. Source

Milien M.,Institute Francais Of La Vigne Et Du Vin Ifv | Renault-Spilmont A.-S.,Institute Francais Of La Vigne Et Du Vin Ifv | Cookson S.J.,French National Institute for Agricultural Research | Sarrazin A.,Institute Francais Of La Vigne Et Du Vin Ifv | Verdeil J.-L.,CIRAD - Agricultural Research for Development
Scientia Horticulturae

Successful grafting in plants requires the development of a functional vascular system between the scion and the rootstock. Understanding the spatial organization of the graft interface is important to the evaluation of new rootstock genotypes and to the development of new grafting technologies. Until now the graft interface has only been studied using 2D classical histology and low resolution 3D magnetic resonance imaging. Here we investigate the ability of X-ray tomography to examine the graft interface of Vitis vinifera in high resolution and in 3D.Data were collected using a Skyscan 1076, scanning parameters, such as, X-ray energy, filter selection, pixel size and rotation angles, were optimized to study the particularities of the graft interface. The X-ray tomography technique was then used to evaluate graft quality. Two young vines were compared; one graft was classified as of 'good' quality, whereas the other was classified as of 'bad' quality. We were able to distinguish the " omega cut" , the pith, the phloem and the xylem vessels in the images. The analysis shows several differences between the two vines. In the good graft, tissues appear well-connected in the wood and phloem, and had a regular structure; the wood appears homogenous with a lot of vessels that form a compact mass. By contrast, in the bad graft, the structures appear disorganized and not completely connected.Numerous new vessels, continuous between the scion and the rootstock, are visible in the " good graft" whereas only few ones are visible in the " bad one" It is the first time, to our knowledge, that 3D imaging of the graft interface and the vascular connections across it have been reported, opening new avenues for graft quality assessment in woody plants. © 2012 Elsevier B.V. Source

Picque D.,French National Institute for Agricultural Research | Lieben P.,Institute Francais Of La Vigne Et Du Vin Ifv | Chretien Ph.,Institute Francais Of La Vigne Et Du Vin Ifv | Beguin J.,Institute Francais Of La Vigne Et Du Vin Ifv | Guerin L.,Institute Francais Of La Vigne Et Du Vin Ifv
Journal International des Sciences de la Vigne et du Vin

Aim: The objective of the present study was to assess the ripening of grapes collected at different stages of maturation between the "véraison" and harvest periods from mid-infrared spectroscopy (MIRS) analysis. Methods and results: Grape berries of Cabernet Franc collected in two locations of the Loire Valley region (Touraine and Anjou), from 28 vine plots and during two vintages (2005 and 2006) were analysed. With principal component analysis (PCA) of spectral data of grape musts, different levels of ripening were described during the three to four weeks before harvest. A separation according to origin (Touraine or Anjou) was also observed and confirmed by the results of partial least squares (PLS) discriminant analysis (88 % of correct classification). Similar evolutions and geographical discriminations were obtained for specific physicochemical parameters. By PLS regression, good predictions of (titratable acidity and sugar concentration from berry spectral data were obtained, with root mean square error of prediction (RMSEP) of 0.53 g/L for titratable acidity (expressed in H2SO 4) and 8 g/L for sugar concentration. Moreover, when the data from only one of the regions were considered, the predictions of titratable acidity and sugar concentration were improved and those of real acidity (pH) and maturity index were then satisfactory. The RMSEP values for samples from Touraine and Anjou were reduced, respectively, to 0.05 and 0.02 units for pH, 0.4 and 0.12 g/L for titratable acidity (expressed in H2SO 4), 6.6 and 3.2 g/L for sugar concentration, and 5 and 2.2 units for maturity index. Conclusion: Spectroscopic and classic chemical analyses of grape berries yielded highly similar results. The evolution of berries from "véraison" to harvest can be characterized according to both time course and region. The samples showed similar PCA results for chemical and IR spectra parameters. PLS regression between chemical and spectral data showed that Fourier transform IR is a good method to predict acidity and sugar concentration throughout ripening. And the results for these parameters, as well as for pH, maturity index and anthocyanin concentration, are improved if the regressions are calculated from sample sets restricted to a single growing region. Consequently, a calibration model is required for each grape geographical origin. Significance and impact of the study: The potential of MIRS was demonstrated for the quantification of the main indicators of maturity during berry ripening. Furthermore, these spectra can be used to estimate grape maturity in particular in reference to a spectral database established over several years of study. The association infrared spectroscopy, chemometric methods and database will help to monitor ripening and to determine the optimum harvest date. © Vigne et Vin Publications Internationales (Bordeaux, France). Source

Maul E.,Julius Kuhn Institute | Sudharma K.N.,Julius Kuhn Institute | Kecke S.,Institute Francais Of La Vigne Et Du Vin Ifv | Marx G.,Institute Francais Of La Vigne Et Du Vin Ifv | And 44 more authors.
Vitis - Journal of Grapevine Research

The objective of the European Vitis Database is to safeguard and enhance germplasm by monitoring its preservation. Two issues are strongly related to that purpose: (1) participation of collections covering almost all grape biodiversity and (2) assessment of accessions trueness to type. In the scope of the European project GrapeGen06 efforts have been made towards both objectives. The 35 participating grape germplasm repositories are found between the Iberian Peninsula and Transcaucasia, thus covering a broad range of grape diversity. Altogether they maintain 32,410 accessions. However with respect to biodiversity, gaps are still evident and further collections need to be included and trueness to type assessment absolutely needs to be pursued to organize duplication of endangered genotypes. Within the GrapeGen06 project focus was laid on the establishment of a database conferring the collection holders a high degree of responsibility and independence. Hence for the first time in a European Central Crop Database an on-line uploading application and an interactive modification system for data administration was implemented. These innovations disburden the database manager and offer the curators of collections more flexibility. Prerequisites for data import, descriptors applied, access levels, database contents, uploading, export and search functions are described. Source

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