The role of genetics in adapting grapevine production to environmental challenges

Abstract

The wine producing sector currently faces major challenges, particularly adapting to climate change and transitioning toward agroecological practices – notably reducing the use of plant protection products and synthetic fertilizers. The choice of plant material (grapevine varieties, clones, and rootstocks) is a key lever to address these challenges. While breeding programs have successfully produced varieties resistant to downy and powdery mildew, selecting genotypes tolerant to abiotic stresses has proved to be far more difficult. Difficulties include defining the target traits that determine tolerance to abiotic stresses, choosing and applying relevant abiotic stress scenarios, and using the timescales necessary to assess tolerance in a perennial crop species. For example, maintaining yield is a complex trait that requires long-term monitoring, always directly in the vineyard.

Abiotic stresses relevant to viticulture include water deficit, high and extreme temperatures, and soil salinity (often caused by intensive irrigation in dry climates). Although the genetic contribution to the variability of grapevine responses to these stresses has been demonstrated, the underlying genetic architecture remains poorly understood and is often complex, potentially involving additional mechanisms, including epigenetic regulations. In rootstock breeding programs, these results are not yet consolidated between different genetic backgrounds, and the underlying physiological mechanisms remain poorly characterized.

Research in this field faces significant challenges. The wide range of stress scenarios (applied at different developmental stages, intensities, and durations) leads to a large variability in results. Furthermore, rootstock × scion × environment interactions add layers of complexity to interpreting results. Beyond studying individual stress factors, multi-stress studies (both in controlled conditions and in the field) are essential and need to be developed. Ultimately, it is crucial to consider the combined genotype of the scion/rootstock chimera under stress conditions that are likely to be experienced in the future.