Comparative Vine-to-Wine Assessment of Malvasia di Candia Aromatica Grafted onto Four Rootstocks: Mineral Nutrition, Grape Composition, and Wine Volatile Profile

Rootstock selection is associated with differences in grapevine mineral nutrition, vegetative performance, grape composition and potentially wine characteristics. This study comparatively assessed Malvasia di Candia Aromatica (Vitis vinifera L.) grafted onto 1103 Paulsen (1103 P), 420 A, Teleki 5BB and SO4 in a rainfed commercial vineyard in Crete. The evaluation integrated field measurements, petiole mineral analysis, grape composition, standardized microvinification, basic wine analysis and GC-MS volatile profiling. Petiole mineral composition showed the clearest differentiation among graft combinations, with eight of nine measured elements remaining significant after false-discovery-rate correction. 1103 P was characterized by the highest P and Mg concentrations, 420 A by the highest Ca and comparatively low Na and K, Teleki 5BB by comparatively high Zn, and SO4 by the highest K and Mn and the lowest Mg, Cu and Zn. At harvest, must pH was the most robust response (3.75 in 1103 P compared with 3.27–3.42 in the other rootstocks), whereas soluble solids and titratable acidity did not differ significantly. Three independent grape lots per rootstock were microvinified under a common protocol. Wines from Teleki 5BB and SO4 showed higher alcoholic strength (12.10 and 12.21% vol, respectively) than those from 1103 P and 420 A (11.51 and 11.47% vol). Three volatile compounds showed nominal differences among rootstocks, but none remained significant after multiple-testing correction, and PERMANOVA did not detect significant overall separation of volatile profiles. Overall, rootstock-associated differences were biggest for mineral nutrition and must pH, intermediate for selected basic wine characteristics, and weak for wine volatile composition. These findings highlight distinct vine-to-wine response profiles among graft combinations while supporting cautious, cultivar- and site-specific interpretation under Mediterranean rainfed conditions.