Greffadapt: a relevant experimental vineyard to speed up the selection of grapevine rootstocks

Abstract

Context and purpose of the study ‐ Grapevine is grown as a grafted plant since the end of the 19th century. The large majority of rootstocks were selected at this period. Among the large diversity of existing rootstocks, few of them are commercially used in the vineyard. However, rootstocks could be considered as a relevant way of adaptation to climate change context because they have no major impact on wine typicality unlike the changes of scion varieties. Rootstock selection is a long term process. Consequently, in addition of the selection of new bred genotypes, characterizing existing rootstocks already used in foreign countries or available in germplasm collections, is a complementary strategy to allow a faster enlargement of the rootstock range available for winegrowers.
Material and methods ‐ GreffAdapt is an experimental vineyard created to get and update the agronomical characteristics of 55 rootstocks. These rootstocks were grafted with 5 scions in 3 blocks of 5 vines each. Blocks were defined according to soil resistivity measurements and the statistical power of the experimental designed was calculated. Before planting, the genetic identity of each genotype was checked with 20 microsatellites markers and their sanitary status was analyzed with ELISA assays. Planting occurred in 2015, 2016 and completed in 2017. The fresh weight of each plant was determined at grafting and the pruning weight of each vine has been recorded annually since the plantation.
Results ‐ Phenotypic data were analyzed according to the parentage with the three main genetic background (V. riparia, V. rupestris, V. berlandieri). The weight of each plant at the grafting time and the pruning weight since the plantation were assessed. The significant relation between these variables was discussed taking into account annual data sets. The first results showed that the range of conferred vigor among the rootstock panel was large enough to identify the required diversity, necessary to fit different production objectives in the French vineyard.
Overall, GreffAdapt is a very unique experimental facility to speed up the selection of rootstocks and to analyze the relationship between conferred vigor and drought tolerance, two major selection criteria for rootstocks.