Evaluation of criteria to assist the selection of good quality grafted grapevines prior to their commercialisation

The production of grafted grapevine plant material is a complex process with many steps running over at least one year, from grafting to final sorting in nurseries. To reach the market in France, grafted grapevines must meet three criteria by law: resistance to a manual graft union test (or thumb test), a minimum number of three roots and a woody, lignified stem which has grown from the bud of the scion wood of at least 2 cm long. This study aimed to evaluate the possibility of using visual criteria to select good quality grafted grapevines, without the need to do the thumb test because the thumb test is manual and therefore very subjective; the test depends on the strength applied by the person who realises it. This study was done on 22 scion/rootstock combinations with different degrees of grafting success, i.e., producing different proportions of marketable plants after one year in the nursery. The three legal criteria currently used to select marketable grafted grapevines in France as well as other external and measurable criteria such as the length of lignified stem and diameter, the number of thin and thick roots, and rootstock wood diameter were measured on the 22 scion/rootstock combinations. Variation in the values for these different criteria was observed and correlations between the criteria and the number of marketable plants were studied. This data was then analysed to determine which visible criteria contribute most to identifying marketable grafts. The percentage of marketable grafts was most strongly correlated with the thumb test and positively correlated with the length of the lignified stem. The variables with the highest predictive effect for identifying marketable plants (other than the thumb test) were the number of large roots and the length of the lignified stem. The possibility of using visible criteria to screen for good quality grafted plants is discussed, but no single, or combination of criteria, was sufficiently strongly correlated with the percentage of marketable plants to replace the thumb test

GRSPaV, a prevalent virus in most of the Vitis species

Grapevine rupestris stem pitting-associated virus (GRSPaV), is closely related to the disease Rupestris Stem Pitting, a component of the the rugose wood disease (Zhang et al., 1998, Meng et al. 1998). GRSPaV is commonly detected in cultivated grapevine worldwide. The hypothesis of co evolution between the ancestor of GRSPaV and Vitis species associated to its diffusion in scion varieties via the grafting was previously proposed (Meng et al., 2006). To test this hypothesis we investigated the GRSPaV infection of numerous grapevine accessions never grafted

Grapevine Vein Necrosis is not Exclusively Associated to GRSPaV Group 2 Molecular Variants

International audienc

Grapevine Vein Necrosis syndrome is not exclusively associated to GRSPaV group I and II molecular variants

National audienc

The decline of the young vines grafted onto 161-49 C

International audienceThe 161-49 C is a rootstock widely used in France. In 2010, its surface represented more than 4% of potential of the nurseries (82 ha), ranking in 8th position for rootstock varieties in France (statistics 2011 from FranceAgriMer). Although ten clones are officially registered in the French catalogue, clones 176 and 198 represent 85% of the total potential of production. For 6-8 years, severe declines of young vines grafted with this rootstock have been reported in several vineyards of Languedoc (south of France). While the number of declines increased in Languedoc, similar cases were reported in other French and foreign vineyards. Given the importance of the problem for the viticulture industry, a survey was performed in France to identify affected plots, assess the extent of decline, and to try to identify factors potentially involved in the decline. The first goal of this paper is to report main results of this survey, which was performed on about 230 plots. Another aim of this study is to describe the specific symptoms associated with the syndrome, which can be confused with several other issues (tyloses, black-foot disease, viruses, physiological problems, soil infertility, etc.). Vines sampled in several plots were submitted to a range of observations and anatomical analyses. In this paper, we present and discuss the symptoms and the anatomy alterations associated with the disorder

Occurrence of Grapevine Pinot gris virus in France: field monitoring in diverse viticulture areas

Occurrence of [i]Grapevine Pinot gris virus[/i] in France: field monitoring in diverse viticulture areas. 16. Rencontres de Virologie Végétale (RVV 2017

First report of Grapevine hammerhead viroid-like RNA infecting grapevine (Vitis vinifera L.) in France

First report of Grapevine hammerhead viroid-like RNA infecting grapevine ([i]Vitis vinifera L.[/i]) in Franc

Viral sanitary status and genetic diversity of Rupestris stem pitting - associated virus in french syrah clones exhibiting various susceptibility levels to decline

National audienceVirus detection was realized in 22 clones of Syrah, chosen for their various susceptibility towards Syrah decline, by RT-PCR amplification. All these clones were free of 14 grapevine viruses whereas they all showed clearly the presence of RSPaV. The structures of RSPaV population in Syrah clones presenting opposite behaviours towards Syrah decline were studied. The putative implication of RSPaV in this syndrome is discussed

Visualization of the 3D structure of the graft union of grapevine using X-ray tomography

International audienceSuccessful 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

The vineyard declines due to the quality of the plant

National audienc