French rootstock review finds stronger effects on vine growth and yield than on grape chemistry

A broad review of rootstock trials

Conducted from 2023 to 2026 under France’s national vineyard sustainability plan, PGVigne.net assembled findings from about 60 experiments involving roughly 20 rootstocks. The project sought both to consolidate knowledge of widely used materials and to improve understanding of less common options, including rootstocks originating outside France.¹

The work drew on trials by CTNSP selection partners, the French Wine and Vine Institute’s site at Espiguette, INRAE in Bordeaux and vine nurseries. Taran Limousin, a plant material engineer at the French Wine and Vine Institute (IFV), described rootstock selection as an important means of adapting vineyards to climate change because it affects vine vigor and tolerance of water shortages.¹

Yield, vigor and local variability

The review confirmed that rootstocks differ in their effects on vigor and yield, but found that outcomes are strongly shaped by climate, soil and the scion variety grafted onto them. Arthur Frohely of the Alsace wine interprofessional committee therefore said the findings should be treated as broad tendencies rather than fixed rules.¹

The largest yield increase associated with a rootstock in the analysis was 14%, which Frohely characterized as moderate. Sébastien Julliard of the Charentes vineyard conservatory also cautioned that the most vigorous rootstocks do not necessarily produce the highest yields.¹

Rootstock choice had only a very limited effect on acidity and alcohol content. The findings consequently place its main value in long-term agronomic decisions concerning vine structure, productivity and resilience, rather than in directly controlling those components of grape composition.¹

Options for drought and practical constraints

The project identified the lesser-known, vigorous rootstocks 333 EM and 140 Ru as potentially better adapted to dry conditions. However, Julliard said some highly vigorous materials are harder to produce and therefore less attractive to nurseries; he also noted that candidates such as 197-17 Cl are unsuitable for calcareous soils.¹

Measurements at IFV Grau-du-Roi produced an average plant-establishment rate of 63%, with the scion having more influence on establishment than the rootstock. The project also surveyed nurseries about rootstock cultivation and grafting practices, complementing the field results with commercial and technical information.¹

Guidance and further evaluation

The principal findings are expected to be incorporated into the PlantGrape website to help growers and advisers compare rootstocks and make planting decisions. A webinar presenting the main PGVigne.net results is scheduled for December 15.¹

Separately, CTNSP member organizations have begun assessing additional rootstocks for possible inclusion in France’s official national catalog. Evaluations in mother-vine blocks and of transmitted traits are taking place under northern, southern and oceanic conditions, with trial areas in Champagne, Aude and Charentes; since 2026, lighter protocols have extended assessment of the strongest candidates to other regions.¹

By 2028, the group expects to determine whether already registered varieties including BC 2, 1447 Paulsen and 34 EM should be propagated more extensively. It may also consider registering materials such as Ramsey and 107 Vidal.¹

Implications for vineyard renewal

The research comes as vineyards in France and elsewhere face increasingly frequent heat and water stress. Because rootstock choices are made well before full production and are difficult to reverse after planting, stronger evidence on vigor, yield, drought tolerance and nursery performance could guide vineyard renewal and ultimately affect the stability of grape supplies.¹