Melatonin for improving grapes quality of “Halawani” cultivar

Abstract

Grapevines are among the most commonly grown fruits on Earth and are also the most consumed fruits in the world. The nutritional and economic values of grapes are commendable, as are the consumption of the fruit itself or its derived products, such as juices, wines and raisins. Melatonin, a hormone typically associated with the control of sleep in humans, also has a significant role in the process of fruit ripening. The current study was intended to investigate the effects of the foliar application with melatonin on enhancing the grapes quality. The commercial melatonin was foliarly applied in three concentrations (0, 3 and 6 mg/L) at three different phases: upon flowering, at pre-veraison phase and at veraison phase. Fruits were gathered and assessed based on their physical and chemical properties. The findings showed that melatonin application had a significant effect on the grape chemical properties as measured by grape flesh and seeds contents of TSS, total acidity, total sugar, anthocyanin, antioxidants, phenols, flavonoids and resveratrol. Melatonin at 6 mg L^-1 was the most effective and resulted in significant increases of fruit and seed contents of total sugar (9.25 and 9.59%), anthocyanin (16.16 and 16.99%), phenols (6.37 and 6.31%), flavonoids (16.64 and 16.15%), and resveratrol (10.7 and 9.99%). Further research is necessary to fully comprehend the intricate relationship between melatonin and bioactive compounds, this would lead to the development of strategies to increase the amount of melatonin in grapes.