Effect of harpin applications on berry skin color and bioacti̇ve compounds of Red Globe grape cultivar

Some pink-red table grape varieties in the world and in our country cannot reach the desired intense and uniform color in the berry. This situation causes a decrease in the potential economic value of grapes. Different elicitors are used to improve the color quality of grapes. Harpin proteins (HrP) are biotechnologically developed bio-activators. They are elicitors that trigger the synthesis of bioactive compounds when applied to plants during their development period. In this study, aimed at comparing the effect of HrP over the bioactive compounds and color improvement of Red Globe table grape grown in Tokat ecology. Beta-HrP protein 120 ppm (400 g/Ha) was applied to 'Red Globe vines three times at the beginning of veraison. Five samplings were carried out for both the treated and control grapes until commercial harvest. In the samples taken, TSSC, total acidity, pH, maturity index, berry hardness, total anthocyanin, total phenolic, antioxidant capacity, cluster color uniformity and color values were determined. Anthocyanin content values at harvest were 3 times higher in grapes treated with HrP than in control grapes (P < 0.05). In addition, the total phenolic content and antioxidant capacity of the treated grapes were 9% higher and 20% higher than the control. In general, HrP treatment improved the color of the fruits and positively affected other quality characteristics as well.