Intracultivar genetic diversity in grapevine: Water use efficiency variability within cv. Grenache

Area of Science:

• Viticulture and Plant Physiology
• Climate Change Adaptation in Agriculture

Background:

• Traditional genotype selection relies on agronomic and grape composition, which may not predict climate change resilience.
• Understanding ecophysiological responses is crucial for identifying genotypes adapted to changing environmental conditions.

Purpose of the Study:

• To assess the variability in water use efficiency (WUE) among 13 Grenache genotypes over three seasons.
• To identify reliable physiological indicators for selecting grapevine genotypes suited for future climate conditions.

Main Methods:

• Field assessment of WUE at leaf, grape, and plant levels across three growing seasons.
• Analysis of genotype-specific regressions to determine intrinsic WUE responses to vine water status.
• Evaluation of net photosynthesis, stomatal conductance, and carbon isotope discrimination as physiological indicators.

Main Results:

• Significant genotypic variability in WUE was observed at all measured levels (leaf, grape, plant).
• A consistent pattern of WUE was found across levels, despite interannual environmental variability.
• Intrinsic WUE responses to vine water status varied significantly among genotypes.
• Carbon isotope discrimination in grapes and the relationship between net photosynthesis and stomatal conductance proved reliable indicators.

Conclusions:

• A multi-level methodology effectively quantifies intracultivar variability in Grenache.
• Specific physiological indicators can identify Grenache genotypes with superior water use efficiency for climate change adaptation.
• Focusing on ecophysiological traits is essential for selecting resilient grapevine genotypes.