Effect of preharvest methyl jasmonate and methyl salicylate applications on the quality and postharvest life of “Eva” grapes

Abstract

There is growing interest in recovering the local “Eva” grape (Vitis vinifera L.) from Los Santos de Maimona as a table grape. This study evaluated preharvest methyl jasmonate (MeJA) and methyl salicylate (MeSA) applications as strategies to improve quality and extend shelf life. In a commercial vineyard, clusters received three applications from veraison onwards, using 10 mM MeJA or MeSA. Treated and control grapes were harvested at commercial maturity, packed in 5-kg boxes and stored for 40 days at 0 °C and 90 % relative humidity. Physicochemical, bioactive and microbiological parameters were assessed after 10, 20, 30, and 40 days. MeJA treatment was beneficial, particularly for antioxidant activity, malic-acid levels and firmness after prolonged storage. Microbiological responses to both elicitors were non-linear. Significant differences appeared from day 20, with a general increase in counts on day 30 followed by stabilisation or a slight decrease. MeJA produced lower microbial counts from the beginning and maintained values equal to or below the control after day 20, indicating an early protective effect. MeSA showed no initial protection but did not compromise long-term microbiological stability. Preharvest elicitor application therefore improved several berry-quality parameters without adversely affecting microbiological stability, although additional vintages are required to validate the results.

References

1. Neira Piotrowski, C. F. (2023). Efectos de diferentes fitorreguladores y elicitores sobre la composición química de bayas de uva de mesa (Vitis vinifera L.) durante la maduración Universidad de Chile. https://doi.org/10.58011/fz0c-pd94
2. International Organisation of Vine and Wine (OIV). Compedium of International Methods of Wine and Must Analysis, 2022nd OIV ed.;International Organisation of Vine and Wine (OIV): Paris, France, 2022; Volume 1, ISBN 978-2-85038-052-5
3. Valdés Sánchez, M. E. Effect of Preharvest Methyl Jasmonate and Methyl Salicylate Applications on the Quality and Postharvest Life of “Eva” Grapes. Recording of the presentation delivered at Enoforum Spain 2026, Zaragoza, 20–21 May 2026. Available soon on Infowine Premium: https://vinidea.it/es/brand/infowine/

Acknowledgements

This work was funded by the project “Innovation in Agronomy and Postharvest Treatment of Eva Grapes for Competitive Improvement and Recovery of the Variety in Extremadura” (RECUP_EVA), Operational Group EVA-BEBA, PGO/52/2022, Regional Government of Extremadura, EAFRD and RDP. M.P.V. acknowledges grant JDC2022-049532-I, funded by MICIU/AEI/10.13039/501100011033 and the European Union NextGenerationEU/PRTR.