Methyl jasmonate fumigation enhances crop yield and delays physiochemical quality changes by modulating the secondary metabolism in green bell pepper.

Background: The green bell pepper (Capsicum annuum L.), of the 'Lamuyo' type, is a highly valued vegetable owing to its excellent organoleptic and nutritional properties. However, these properties are subject to deterioration during postharvest storage, which in turn limits the shelf-life of the pepper fruit. The present study examined the impact of preharvest treatment with 0.1 and 1.0 mmol L^-1 methyl jasmonate (MeJA) administered via foliar spraying on crop yield and both physiochemical and functional fruit quality at harvest and throughout a 28-day postharvest storage period at 7 °C.

Results: The study was conducted over two seasons (2020 and 2021) on green pepper fruit. The findings indicated that the application of MeJA had a favourable impact on crop yield in both growing seasons. Additionally, the treated peppers showed a 1.17-fold reduction in weight loss and respiration rate, accompanied by augmented firmness, hue angle values, total soluble solids and total acidity in comparison to the controls. Applying 0.1 mmol L^-1 MeJA was found to be the most effective way of maintaining quality at harvest and during postharvest storage over two consecutive seasons. Furthermore, MeJA treatments increased the levels of the antioxidant system by stimulating the activities of ascorbate peroxidase, catalase and peroxidase enzymes, as well as increasing the phenolic content and the total antioxidant activity. This could lead to an enhancement of the health benefits after the consumption of these treated peppers.

Conclusion: The study demonstrates that the most efficacious concentration for enhancing yield and quality parameters by stimulating the secondary metabolism of peppers was 0.1 mmol L^-1, a finding that was corroborated in the second season of 2021. The effects of MeJA on green pepper fruit may have significant commercial implications, as it has the potential to enhance quality at harvest and maintain it during postharvest storage. This may result in a delay in the onset of quality losses and the oxidative stress associated with fruit senescence, thereby extending the shelf-life of the fruit after prolonged storage at optimal temperatures. © 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.