Effect of different canopy managements on microclimate and carbon allocation in Vitis vinifera cv Chardonnay

Retrotransposons, particularly of the Ty-Copia and Ty-Gypsy superfamilies, represent the most abundant and widespread transposons in many plant genomes. Grapevine is no exception and it is clear that these mobile elements have played a major role in the evolution of Vitaceae genomes. While speculation abounds around the possible role of transposons in plant genomes, outside of the rather obvious involvement of retrotransposition in fueling genome expansion, there is little clarity of the actual role these elements have in both developing new genetic variation and in modulating epigenetic responses within genomes to changing climate. To this end we have been exploring de-novo assembled Sauvignon blanc and Pinot noir genomes with a view to catalogue retrotransposon loci to determine the structural intactness and thus age of insertion variation across a small number of clonal linages of these 2 varietals in an attempt to identify ‘live’ TE loci.

Grapevine (vitis spp.) Is one of the major and most economically important fruit crops worldwide. Unlike other cropping systems, viticulture has ancient historical connections with the development of human culture and with the socio-cultural background of grape-growing areas. The vitis genus is characterised by high levels of genetic diversity, as result of natural genetic mutations, which are common in grapevines and further assisted by ongoing vegetative propagation.

The potassium (K) supply characteristics and clay mineralogies of a population of Western Cape soils were investigated to determine their potential effects on vine K uptake and wine quality. The total K contents of granite-, shale- and sandstone-derived soils varied, averaging 33.7, 26.1 and 4.5 cmol(+)/kg, respectively. Corresponding M NH4Cl exchangeable soil K levels were: 0.172, 0.042 and 0.035 cmol/kg.

Molecular markers of wine oxydation, such as sotolon or Strecker’s aldehydes that induce respectively nut or curry and boiled vegetables or wilted rose odors, can be percieved as a default by consumers. These volatile compounds are especially formed during the premature aging of wine, but it is likely that several contributing compounds are still unknown as is their combined contribution. This study was carried out to identify the markers of oxydation in Chardonnay wine by Gas Chromatography Olfactometry (GC-O) and to study the impact of these markers on the complex wine aromatic buffer using the Olfactoscan approach.A Chardonnay wine (2018-vintage), taken after malolactic fermentation without sulphites addition, was submitted to an artificial oxidation to simulate more or less prononced premature oxidation. Volatile compounds were extracted by Solid-Phase Extraction (SPE) and analysed by GC-O with a panel of 13 trained subjects. The same extract was also submitted to a second analysis based on the Olfactoscan technique, which allowed to evaluate the impact of each volatile compounds on the complex aromatic buffer of a non-oxidized wine delivered as background odor. Preliminary results revealed three types of behavior. On the one hand, several odor zones appeared only with the background odour, suggesting a synergy effect induced by the compounds in the aromatic buffer. Conversely, odor-active compounds could not be perceived within the background odor suggesting a masking effect. Finally several compounds were found to contribute as key odorants for wine oxydation once mixed with the aromatic buffer. These compounds are still to be identified using complementary techniques.

An organoleptic defect, called fresh mushrooms off-flavor (FMOff), appeared in wines and spirits since the 2000’s. Numerous researches demonstrated that octen-3-one, 3-octanol and octen-3-ol (C8 compounds) were involved in the mushroom off-flavor in wines