Preservation effects of pre-harvest methly-jasmonate (MeJA) applications on star blue berry variety

In this thesis study, the effects of different preharvest methyl jasmonate (MeJA) doses on the storage performance of the 'Star' blueberry cultivar were investigated. Fifteen days prior to the estimated harvest date, MeJA at various concentrations was applied to blueberry plants as a foliar spray. For the blueberry plants, MeJA was applied at concentrations of 0 (control), 0.5 mM, and 1 mM, mixed with 0.01% Tween-20 as a surfactant–adjuvant. For the control group, only water and the surfactant–adjuvant mixture were applied. Blueberry fruits harvested from MeJA-treated and untreated plants were stored for 35 days at 2 °C and 90–95% relative humidity. During storage, the fruits were removed at 7-day intervals, and the physical and chemical changes that occurred were determined. At harvest, analyses included yield per plant, average fruit weight, fruit width and length, skin color, flesh firmness, wax layer amount, soluble solid content (SSC), pH, and titratable acidity (TA). During storage, weight loss, decay incidence, skin color, flesh firmness, SSC, TA, total phenolic content, vitamin C, anthocyanin content, and antioxidant activity were evaluated. According to the findings obtained from the physical and chemical analyses, MeJA treatments at different doses (0.5 and 1 mM) did not have a statistically significant effect on fruit length, hue angle, fruit firmness, titratable acidity, pH, phenolic content, antioxidant activity, or anthocyanin levels. During storage, MeJA application produced statistically positive results in terms of weight loss, wax layer amount, soluble solid content, and vitamin C values. MeJA treatment was found to be effective in reducing weight loss during storage. A decrease in wax layer amount was observed as the storage period advanced. Fruits treated with MeJA had the highest vitamin C content. Overall, MeJA application had a positive effect on the quality attributes of 'Star' blueberries stored for 35 days.