BUSCADOR RECOLECTA

Olive growing is undergoing a transition from traditional cultivation systems to a more technological model characterized by increased mechanization and a higher density of plants per hectare. This shift implies the use of less vigorous varieties that can adapt to the new system. Most traditional varieties are highly vigorous, and breeding programs can provide solutions to this challenge. This study investigates the parental effect on different agronomic and olive oil characteristics and its role in breeding programs. The objectives were to evaluate and characterize different agronomic and olive oil traits in the progenies from ‘Arbosana’ x ‘Sikitita’ cross and its reciprocal cross ‘Sikitita’ x ‘Arbosana’. The results showed a high variability of the characters evaluated in the progenitors of the reciprocal crosses. The highest coefficients of variation were observed in traits related to ripening index, phenolic compounds, polyunsaturated fatty acids, and D5-avenasterol, with phenolic content exhibiting the greatest variability. No statistically significant maternal effect was detected for any of the evaluated traits, although a slight positive maternal effect was systematically observed in the mean values of the evaluated traits. These results suggest that the maternal effect on olive is quite subtle, although due to a slight tendency of the maternal effect in the descriptive analyses, future studies are suggested to understand in depth the possible maternal effect on olive breeding.

The olive tree (Olea europaea subsp. europaea L.) is one of the most important perennial crops in the Mediterranean Basin. Olive Scab, caused by the fungal species Spilocaea oleagina, a member of the Venturiaceae family, is among the most significant diseases affecting olive cultivation, prompting farmers to spend millions of euros annually on fungicides for its control. The fungal genus Venturia includes highly specialized species responsible for diseases in other crops, such as Apple Scab, caused by V. inaequalis. One of the most effective control strategies for Apple Scab has been developing and using resistant varieties. However, in the case of Olive Scab, genetic resistance remains relatively underexplored. In apples, breeders have identified approximately 20 resistance genes against V. inaequalis, known as Rvi genes, over recent decades. In this study, we identified and characterized four homologous genes to the Rvi family in olive, analyzing their genomic organization and expression profiles in silico. A total of 14 homologous sequences were identified in the olive genome, all sharing conserved domains typical of the leucine-rich repeat (LRR) superfamily, widely associated with plant immune responses. Functional annotation using gene ontology indicated enrichment in categories related to stimulus response and diverse biological processes. Notably, homologous sequences corresponding to apple proteins linked to V. inaequalis resistance exhibited high expression levels in response to biotic and abiotic stresses. These results indicate that olive trees may harbor resistance mechanisms analogous to those observed in apples, providing a foundation for further research into olive disease resistance and breeding programs.