Scaling disease-resistant grape varieties adoption: optimization of the ampelographic platform and management practices in Switzerland and Europe

Abstract

Grape breeding has benefited from a long and worldwide effort to develop new varieties able to control major diseases such as downymildew, caused by Plasmopara viticola, and powdery mildew, caused by Erysiphe necator. The cultivation of disease-resistant grape varieties (DRV, also known as Pilzwiderstandsfähige, or PIWI) is expanding to reduce the negative health, environmental, and socio-economic impacts of plant protection products (PPP) in viticulture. However, viticultural regions are characterized by different climatic conditions and wine production typicity, highlighting the need for adapted varieties and viticultural-oenological practices. With the aim of scaling grape DRV-PIWI adoption, more than 40 recent grape varieties obtained across breeding centres in Europe (Switzerland, Germany, France, Italy, Austria, and Hungary) are under evaluation in three environmentally different regions in Switzerland: the hilly Lake Geneva coast (Changins College for Viticulture and Enology), the Aargau-Jura hills (FiBL) and the hilly Lake Zurich coast (WeinbauzentrumWädenswil-Agroscope). The agronomic traits and oenological qualities of the varieties, and disease protection tools are evaluated inparallel vintages under the challenge of variable temperatures, rainfall and soil conditions. The efficacy and durability of grapevineresistance are monitored using the OSCAR EU protocol, which includes disease assessments and, for P. viticola, the genotyping of population virulence. The research will develop cross recommendations to support Swiss and European grape-wine growers in choosingsuited grape varieties (Swiss national project ‘OenoPIWI’), monitoring mildew epidemics and populations, and deploying decisionsupport systems (DDS) and PPP (EU project ‘GrapeBreed4IPM’) to produce more sustainable wines.