Effect of preharvest treatment of melatotin on ripening and postharvest qualitative characteristics of strawberry (Fragaria × anannasa cv. Queen Elisa)

The purpose of this study was to investigate the effects of melatonin on the ripening, quality and postharvest life of strawberry and selecting its effective concentrations on strawberry cv Queen Elisa. Melatonin foliar application was performed at five concentrations including zero (control), 1, 10, 100 and 1000 μM in light green fruit stage. To investigate the effect of treatments on ripening process, fruits were harvested at 5, 10 and 15 days after treatment and their growth and physiological changes were evaluated. Also, in order to evaluate the effect of melatonin on postharvest life and quality, fruits were stored at 4 °C for 12 days. The 1000 μM treatment results increased the amount of ABA content and PAL enzyme activity during the ripening process. Also, 10 μM treatment decreased ABA production compared to those of control. The results of postharvest samples showed that fruits treated with melatonin at 100 μM concentration had higher firmness during postharvest, which was associated with higher TSS / TA ratio. In addition to sensory quality, the accumulation of phenol, anthocyanin and ascorbic acid with antioxidant capacity was higher in fruits harvested from 100 μM melatonin treatment compared to control treatment. It can be concluded that the effect of different concentrations of melatonin on the strawberry ripening process showed that the concentration of 1000 μM accelerated ripening compared to the control. Treatment with 10 μM melatonin delayed maturation compared to control samples.