A Portuguese grapevine breeding program focused on enhancing resistance to Plasmopara viticola and Erysiphe necator

Abstract

Downy mildew (Plasmopara viticola) and powdery mildew (Erysiphe necator) are among the most destructive diseases affecting grapevine (Vitis vinifera L.). To address this challenge, several breeding programs have been established worldwide with the goal of developing resistant genotypes. In Portugal, PLANSEL Lda., with continuous support of the University of Évora, has been at the forefront of these efforts, leading a grapevine breeding program since the 1980s aimed at enhancing resistance to both pathogens. The program was initially co-financed by the German state bank KfW and later supported by the Portuguese State through national R&D initiatives, including the AGRO 8.2 project and, fifteen years later, the PDR 784 project (2019–2022). More recently, the PEPAC project (PEPACC115) has continued advancing the program. Within these initiatives, resistance genes against powdery and downy mildew were introgressed into Portuguese autochthonous grapevine varieties through controlled crosses with multiresistant, largely homozygous material (kindly provided by the Julius Kühn Institute, Geilweilerhof, Germany). This work led to the registration of the new cultivar ‘Defensor’ in the Portuguese Catálogo Nacional de Variedades. At present, PLANSEL Lda. maintains a collection of more than 700 F1 hybrid plants currently under evaluation. These genotypes will be further characterized through marker-assisted selection (MAS), aiming to pyramid resistance loci for downy mildew (Rpv1 and Rpv3.1) and powdery mildew (Run1, Ren3, and Ren9). In parallel, 184 PIWI genotypes selected within the breeding program have already been grafted and established in a vineyard for advanced field assessment, including wine quality evaluation through microvinification. In its ongoing breeding program, PLANSEL Lda. collaborates with three Portuguese partners, University of Évora, ATEVA, and INIAV, as well as the German institution JKI-Geilweilerhof, which provides genetic material from its breeding programs. These programs target not only downy and powdery mildew but also additional pathogens, such as black rot (Rgb) and Xylella fastidiosa (Rxf), which will be incorporated into new crosses at PLANSEL Lda. The ultimate objective is to develop new cultivars resistant to both pathogens (known as PIWI) while maintaining close genetic and oenological similarity to Portuguese Vitis germplasm. This approach promotes more sustainable viticulture while enhancing and valorising the identity and quality of Portuguese wines.

Funding

This work is funded by National Funds through FCT – Foundation for Science and Technology under the Project UID/05183/2025.

Acknowledgements

The authors acknowledge the R&D unit MED – Mediterranean Institute for Agriculture, Environment and Development (https://doi.org/10.54499/UID/05183/2025) and the Associate Laboratory CHANGE – Global Change and Sustainability Institute (https://doi.org/10.54499/LA/P/0121/2020). The authors also acknowledge the project VITISAFE – Melhoramento de castas Vitis vinifera Portuguesas com foco na resistência a doenças – um contributo para uma viticultura sustentável (ALT2030- 2024-60), the project “Adaptação da Vitis vinifera às alterações ambientais” (PEPAC-C115- 009440), and the IFP for the “Estágio Profissional” granted to R. Santos and to M. Marques.