Improving stilbenes in vitis Labrusca L. Grapes through methyl jasmonate applications

Among the items preserved in gene banks, the old standard and autochthonous varieties represent an increasing value, since these varieties may have properties to make their cultivation more effective under changing climatic conditions. The increasingly extreme weather is a huge challenge for the viticulture. Collectional varieties can also play important role in protection against pests and pathogens. A genebank ensures not only the preservation of rare varieties, but also gives the opportunity for more knowledge and research of these varieties.

Malolactic fermentation (MLF) the microbial bioconversion of L-malic acid into L-lactic acid, is a pivotal metabolic process that holds fundamental significance for the quality and organoleptic characteristics of some wines. Oenococcus oeni is considered to be the main player in this conversion, and it is globally used as a starter culture for mlf thanks to his capacity to tolerate the harsh wine environment.

This work aimed at setting up a multivariate and geostatistical methodology to map natural terroir units of the viticultural areas at the province scale (1:125,000).

Since some years, the French wine sector faces strategical challenges, all linked to climate change. Multiple issues have been observed like diseases development, early frost, drought, change in the precocity and maturity of grapes, each one resulting in loss of productivity and yield. In France, the varieties proposed today by nurseries are historical varieties that are not well adapted to those changes. Therefore, Mercier Frères, one of the leading grapevine nursery, has decided to start its own research programs, with the help of its laboratory Novatech, to answer the growing demand for new grapevine varieties.

Due to the central role of the ripening timing in the evaluation of the varietal response to the environmental resources, a method to manage maturation curves has been developed. The method produces an index of veraison precocity and overcomes several methodological problems, like the visual evaluation of the veraison point and the multi-annual and multi-varieties data processing. It is based on a statistical and mathematical processing of the sugar ripening curves.