Exploring between- and within-vineyard variability of “Malvasia di Candia aromatica” vineyards from Colli Piacentini

Abstract

Several studies demonstrated how climate and soil may be key drivers of variability at different scales. Zoning studies identified sub-regions leading to distinctive wines, while precision viticulture recently focused on within-vineyard scale. Different vigor zones may show differential canopy growth, yield and fruit composition depicting diverse enological potentials. Despite several studies addressed differences in technological and phenolic maturity of widespread red varieties, few works have explored how within- and between- vineyard variability affects varietal odorous compounds (VOCs) in terpene-based aromatic white cultivars.

The study aims to: describe the aroma profile of “Malvasia di Candia aromatica” (MACA) grapes depending on vineyard and vigor, assess if and how between- and within-field variability affects VOCs during ripening, and identify harvest zones for selective picking (SH) at the estate scale.

The study was performed in 2018 in four variable MACA blocks (V1,2,5,7) where two vigor zones were identified by visual assessment. Per each vineyard a CRB design was considered and 9 vines per treatment identified to assess growth, yield and fruit composition. Per each vineyard technological ripening was monitored weekly; similarly, grapes samples were collected pre-veraison, pre-harvest and at harvest to quantify free and bounded monoterpenes and their derivatives by head space solid phase microextraction (HS-SPME) coupled with gas chromatography–mass spectrometry (GC-MS).

The results show differences among vineyards and diverse enological aptitude. Low vigor zones (LV) had lower pruning wt. and yield vs. high vigor (HV) characterized by heavier tight bunches. LV grapes had higher TSS, pH, phenolics and tartrate compared to the less ripe grapes from HV. Regardless zones, V5 had lower pruning wt and yield vs. the other blocks; however, the less vigorous V5_LV achieved highest TSS, pH, K+ and phenols than V5_HV. Between- and within-field variability influenced grape VOCs at harvest; LV had higher free and bounded VOCs than HV while the lowest spatial variability was observed in V5. Regardless of vineyard and vigor zone the study confirmed that MACA has a monoterpenic profile dominated by geraniol. The results support adoption of SH for exploiting between- and within-field differences of grape aroma potential through production of different wines. The panel confirmed different sensory profiles and aging potential of derived commercial wines.