Aims: the present study was designed to test the hypothesis according to which rootstock effects on scion growth and yield are related to fundamental physiological traits which are expressed consistently and independently of environmental conditions.
Methods and results: Pruning weights and yield components from two independent rootstock experiments are reported. In the first experiment, the effect of two levels (30 and 70 kgN/ha/year) was studied during 15 years on Cabernet-Sauvignon vines grafted onto SO4 and Riparia Gloire de Montpellier (RGM). In the second one, Cabernet-Sauvignon and Merlot vines grafted on SO4 and RGM were submitted to two levels of soil fertility shortly after plantation: control and high (100 kgN/ha/year + irrigation) and data from the plantation to year 6 were recorded. In both experiments, vine vigour and yield were significantly affected by rootstocks and fertilisation/irrigation treatments. No interaction was recorded. The devigorating effect of RGM in comparison to SO4 was observed in both experiments, regardless of other parameters. Cabernet-Sauvignon was more affected by rootstock than Merlot.
Conclusion: Rootstock effects on vine vegetative and reproductive development were consistently expressed, indicating that scion-rootstock interactions are governed not only by adaptative, but also by specific physiological traits.
Significance and impact of study: This work provides information on scion-rootstock interactions which may be useful in rootstock breeding programs and may help to better choose the rootstock according to the scion and the environment.