Uncovering Northeast Portugal grapevine's varietal legacy

Northeast Portugal comprises the wine denominations "Douro" and "Tras-os-Montes". There are more than one hundred grapevine cultivars registered suitable for wine production in these regions (ministerial-orders number 1204/2006 and 383/2017), however only a few are actually used for winemaking. In this sense, the identification of the varieties cultivated in past times may widen the number of varieties and can be an important step to take advantage of all the potential of these regions' grapevine biodiversity. The conservation of these vanishing genetic resources boosts a greater products' diversification and it can be considered strategic in the improvement and valorization of "Douro" and "Tras-os-Montes" PDO wines. Moreover, it is imperative to identify, before to characterize and preserve, plants of late-maturing grape varieties planted in regions with extremely high temperatures and precipitation deficits which still maintain grape yield and produce very well-known quality wines. Hence, the main goals of this study were to prospect and characterize, through nuclear and chloroplast SSR analysis, plants of old vineyards that constitute a broad representation of the grapevine genetic patrimony of "Douro" and "Tras-os-Montes" regions.