GEN4OLIVE successfully completed its planned tasks, delivering significant progress beyond the state of the art in olive pre-breeding. It laid the groundwork for valorising neglected traditional cultivars and structuring new breeding programmes. The phenotyping of over 500 cultivars and identification of early biomarkers for marker-assisted selection (MAS) also enable future genome-wide association studies (GWAS), streamlining breeding processes. Machine learning tools were introduced to modernise cultivar and disease identification.
One of the core activities was the identification and conservation of wild olive populations across the Mediterranean, characterised both agronomically and genetically. Ancient olive trees were also located and evaluated as sources of untapped diversity.
The five participating germplasm banks (GBs) conducted phenotypic evaluations of more than 500 cultivars, assessing phenology, stress resistance, productivity traits, and oil quality. This revealed previously undocumented intra-specific variation in oleic acid and phenolics, relevant for breeding and health claims. All data were made publicly accessible via:
https://www.uco.es/ucolivo/gen4olive/(öffnet in neuem Fenster).
This online platform provides a visual olive cultivars catalogue with high-resolution images of tree architecture, fruits, leaves, endocarps, and branches. Profiles include synonyms, country of origin, and GB locations.
Another key achievement was the study of genotype-by-environment (G×E) interactions using 7 shared cultivars across the five banks. Findings confirmed strong environmental effects on phenology, biotic and abiotic stress sensitivity, and phenolic compounds, while oil fatty acid composition showed genetic stability. As an additional fort, the GBs replicated 15 new cultivars (6 replicates) in the same conditions to enable long-term monitoring of environmental effects.
Genomic and transcriptomic tools identified markers linked to resistance to Verticillium dahliae, Xylella fastidiosa, drought, cold, and fruit bruising. Two miRNAs and several genes related to juvenility were validated as early selection markers. Several plant hormones and metabolites were identified as promising indicators of stress resilience.
So, with all this data, GEN4OLIVE developed a free, intuitive online database of over 500 cultivars and laid the foundation for AI tools for cultivar and disease recognition. These tools are available to the public but require further training to improve robustness across conditions.
The two cascade funding calls successfully engaged SMEs, funding 25 third-party projects.
Collaboration with the International Olive Council (IOC) Food and Agriculture Organization of the United Nations (FAO) led to a major result: the formal inclusion of the Córdoba World Olive Germplasm Bank under the International Treaty on Plant Genetic Resources (ITPGRFA), ensuring long-term preservation and equitable access.
Dissemination included 31 scientific publications, dozens under review, and presence in over 40 conferences and trade fairs. The exploitation strategy identified 11 innovation pathways and produced two patent applications. GEN4OLIVE has made a strong contribution to modernising olive breeding and genetic resource management.
