Evaluation of local minor cultivars and marginal areas to improve wines and increase the sustainability of the district ‘Colli Piacentini’

In several areas, global warming is endangering the sustainability of viticulture. Accelerated sugar accumulation and acidity loss are challenging growers and changing the styles of produced wines. The Italian wine district of ‘Colli Piacentini’ is dominated by local cultivars for the production of white sparkling wines, i.e. ‘Ortrugo’ and ‘Malvasia di Candia aromatica’. In 2017, two strategies were evaluated to counteract the effects of warming trends and, more specifically: i) the ripening dynamics of 20 minor yet autochthonous cultivars were compared with the patterns exhibited by ‘Ortrugo’, trying to understand if local biodiversity can be useful in a rapidly changing scenario; ii) basic chemistry of solutes accumulated in ‘Ortrugo’ and ‘Malvasia di Candia aromatica’ berries was characterized from veraison to harvest in five vineyards located between 165 and 380 m above the sea level (a.s.l.) trying to extrapolate the effect due to elevation. Among the minor cultivars, ‘Barbesino’, ‘Molinelli’ and ‘Bucalò’ were the most promising genotypes as ‘Barbesino’ maintained the highest levels of acidity throughout ripening (+2.8 g L-1 than ‘Ortrugo’ at harvest), whereas ‘Molinelli’ and ‘Bucalò’ had appreciable low ratios between sugars and acidity at harvest (-0.55 and -1.13 than ‘Ortrugo’, respectively). The ripening pattern of ‘Ortrugo’ and ‘Malvasia di Candia aromatica’ changed distinctively as a function of site elevation. At 380 m a.s.l. the evolution of ripening of both genotypes was substantially shifted by 7 and 10 days, respectively, in comparison with dynamics observed in vineyards located at 165 m a.s.l. Preliminary results point out that the reconsideration of local biodiversity and the colonization of formerly marginal hilly areas might be useful tools to maintain and/or increase the sustainability and the competitiveness of the wine district.