What if a vineyard’s strongest defense against fungal disease starts with the grape variety itself? Fritz talks with Dr. Oliver Trapp, head of grapevine breeding at Germany’s Julius Kühn Institute, about PIWI varieties and their role in more resilient viticulture.
Oliver explains how breeders combine resistance from wild grape species with desirable wine traits, why breeding can take roughly 25 years, and how DNA markers help identify resistance genes. Stacking multiple genes may make resistance more durable, but PIWIs still need a thoughtful spray program.
They discuss Calardis Blanc, Calardis Muscat, Calardis Soleil, and Calardis Royale, including disease resistance, ripening, climate fit, and wine styles. The conversation also tackles consumer acceptance: growers can start small, blend, and use direct sales to introduce these wines. Listeners will learn how to evaluate PIWI varieties against site conditions, disease pressure, and market goals.
In this episode, you will hear:
- PIWIs can help reduce fungicide use, but they are not spray-free
- Multiple resistance genes may improve durability
- Match variety choice to local disease pressure and climate
- Start small and introduce unfamiliar wines through blends
- Direct sales can help growers educate consumers
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Resources:
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Today’s Guest:
Dr. Oliver Trapp is the Head of Grapevine Breeding at the Julius Kühn Institute in Germany, where he leads the development of climate‑adapted, fungus‑resistant PIWI varieties that reduce pesticide use while preserving wine quality. He oversees one of the world’s largest grapevine gene banks, advances modern breeding tools like Marker‑Assisted Selection, and serves as Editor‑in‑Chief of VITIS – Journal of Grapevine Research.
Connect with Oliver and follow his research:
- Julius Kühn Institute – https://www.julius-kuehn.de/en/zr/staff/p/oliver-trapp
- VITIS – Journal of Grapevine Research – https://ojs.openagrar.de/index.php/VITIS
- Instagram – https://www.instagram.com/das_jki/
Episode Sponsor:
Today’s episode was brought to you by Vigneron Toy Store and Vintner’s Vault.
Thank you to Vigneron Toy Store for sponsoring today’s episode. Vigneron Toy Store specializes in harvesters, sprayers, frost mitigation equipment, canopy management trimmers, and more. As grape growers themselves, the team can help you select the best equipment for your vineyard’s specific needs. Podcast listeners can save 5% on in-stock machines by entering the promo code Underground on the contact form at vignerontoystore.com.
Thank you to Vintner’s Vault for sponsoring today’s episode! Vintner’s Vault is the #1 winery equipment company that I recommend to my growers, who are also winemakers. Visit TheVintnerVault.com and use the code UNDERGROUND5 (all caps) to save 5% off your online order, or mention that you heard about them on the Vineyard Underground podcast when contacting them for a larger piece of equipment, consulting services, or turn-key packages, and they will provide a podcast listener discount for you.
