Piwi Varieties Under the Mediterranean Sun: When Resistant Grapes Actually Deliver

Summary

European grapevines are under growing pressure from diseases they were never really built to resist. Plasmopara viticola and Erysiphe necator — the fungi behind downy and powdery mildew — demand repeated chemical interventions, which eat into margins and are not exactly kind to the soil. A 2026 paper in the Italian Journal of Food Science by Rossetti and colleagues asks a fairly practical question: can PIWI varieties, which carry some non-vinifera genetics in their background, produce wines people actually want to drink, especially somewhere as punishing as Salento in Puglia? The short answer, it turns out, is probably yes. Merlot Kanthus and Merlot Khorus, both grown at Cantine Due Palme in Cellino San Marco, came out with deeper colour than standard Merlot and held their own — or did better — in blind preference tests with 61 everyday drinkers. Merlot Khorus was the more interesting of the two: its lower pH is a real advantage in a climate where grapes tend to lose acidity fast.

The experimental setup is one of the study's stronger points. Same rootstock (Kober 5BB), same training system (Guyot), same microvinification process across all three wines. That kind of consistency means the differences you see are probably down to the varieties and how they behave in that particular place, not something the winemaker did differently. The obvious caveat is that this is still one cooperative, one harvest, one corner of southern Italy. Promising, yes, but not yet a pattern.

Our take

This study is genuinely useful, though it is worth being honest about where its limits are. One vintage from one spot in Apulia is a thin foundation for broad claims about Mediterranean viticulture, and the framing around sustainable viticulture does quietly imply a larger story than the data can actually support. Rossetti and colleagues are measured in how they write, but the overall package nudges the reader toward bigger conclusions. The sixty-one consumer tasters are a fine starting point, but preference in a lab setting and actually buying the bottle are two different things. That said, the colour and pH data are the real takeaway here, and the experimental design is genuinely clean. Think of it as a solid first step, not a settled argument.

About the author

The piece is signed with initials only — R. T. — which is not unheard of but does make it harder to know who you are actually reading. No external trace of the author turned up. The writing itself suggests someone comfortable with scientific reporting: the terminology is handled well and the study is presented without obvious distortion. Still, a full name matters when you want to weigh the credibility behind the interpretation, and its absence is a small but real gap.

About the publisher

Teatro Naturale is an Italian online outlet covering agriculture, food, and environmental topics. It was founded by Alberto Grimelli, an agronomist and journalist with a particular focus on olive growing, and it pitches itself at both industry readers and the generally curious. The Strettamente Tecnico section tends to maintain a decent standard of technical rigour. One thing worth noting: the site carries advertising from agri-supply companies, which is a potential conflict of interest they do not flag explicitly.