Variability of Constitutive Stilbenoid Levels and Profiles in Grape Cane (Vitis viniferaL.) Depending upon Variety and Clone, Locationin the Vineyard, Pruning Time, and Vintage br

Stilbenoids in grape cane (Vitis viniferaL.) are bioactive compounds relevant for plant defense and the potentialvalorization of this byproduct. Our screening of grape cane from 102 varieties showed constitutive stilbenoid levels in a wide range(557-7748 mg/kg of dry weight). Analyses of genetically distinct clones of selected cultivars unraveled that intravarietal variability(e.g., cv. Riesling, 3236-6541 mg/kg) was higher than that across samples from a single clone but different vineyard positions(3017-3710 mg/kg). Furthermore, stilbenoid levels in samples obtained in October, December, and February (3 years, 2017-2019) showed pronounced quantitative and qualitative variability and the highest yields upon December pruning. For instance,vitisin B and epsilon-viniferin in cv. Pinot Noir and Accent were predominant in 2017 and 2019 (both >90% of total stilbenoids) but notin 2018 (both <55%) when temperatures were high and precipitation low. In brief, we report the variability of stilbenoid levels ingrape cane depending upon genetic and environmental factors.