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.

Dormancy release dynamics in olive tree (Olea europaea L.) reproductive buds as affected by cold accumulation, tree bearing status, and budburst temperature was studied under natural and controlled conditions, using both cuttings and container- and field-grown plants. The chilling necessary for dormancy release was acquired at different times within the bud population, presenting a progressive pattern of reproductive budburst. Once sufficient chilling is accumulated, 20 °C is a suitable temperature for reproductive budburst, although higher temperature, e.g., 30 °C, during dormancy release can inhibit budburst. While the bearing status of trees determined the amount of return bloom, dormancy release followed a similar pattern for previously bearing and non-bearing trees. Concurrent with investigating budburst factors, the use of shoot cuttings was tested as a method for olive dormancy release studies by contrasting with results from whole trees. It was found it to be valid for studying reproductive budburst, thus providing a useful method to screen chilling requirements in cultivar evaluation and the breeding programs currently ongoing in this species. However, the method was not valid for vegetative budburst, with varying results between cuttings and the whole plant., This work received support from European Union Horizon 2020 project GEN4OLIVE (H2020-SFS-2020-1; G.A. No. 101000427) and Spanish Ministry of Science and Innovation projects AGL2005-00930/AGR and AGL2008-02570/AGR., Peer reviewed

IX Congreso Ibérico y XVII Congreso Nacional de Ciencias Hortícolas 2023
5 – 9 junio 2023, Mérida, La estabilidad oxidativa del aceite de oliva virgen extra (AOVE) se refiere a la capacidad del aceite para resistir la oxidación, que puede afectar a su vida útil, calidad y sabor, y se mide como el tiempo de inducción. La estabilidad oxidativa está íntimamente ligada a la composición del AOVE y puede verse afectada por factores como la variedad y el ambiente en el que se cultiva. En este estudio se compararon genotipos seleccionados por sus características agronómicas e idoneidad para el cultivo en seto de alta densidad procedentes del programa de mejora genética del olivo llevado a cabo en el IFAPA y las variedades más comunes utilizadas en este tipo de cultivo: 'Arbequina', 'Arbosana', 'Koroneiki' y 'Sikitita'. Se evaluó la estabilidad oxidativa y composición, en particular respecto al contenido en compuestos fenólicos, del AOVE obtenido en diferentes localizaciones y se examinó la variabilidad genética y la interacción genotipo x ambiente. Los resultados obtenidos muestran la mayor influencia del genotipo en la determinación de estos caracteres, la falta de interacción significativa genotipo x ambiente, el potencial de la mejora genética para seleccionar nuevos materiales adaptados al cultivo en seto y con buenos caracteres de calidad y la relación de la estabilidad oxidativa con otros caracteres de calidad del AOVE., Ayuda PID2020-115853RR financiada por MCIN/AEI/ 10.13039/501100011033 y “FEDER Una manera de hacer Europa” y programa Horizonte 2020 de la UE (grant agreement No. 101000427- GEN4OLIVE). Hande Yılmaz-Düzyaman agradece asimismo la Ayudas para contratos Predoctorales asociada al mismo proyecto y “FSE Invierte en tu futuro”.