Berry Growth and Biochemical Characteristics of cv. Trakya Ilkeren (V. vinifera L.) as Influenced by Various Doses of Pre-Harvest Hydrogen Peroxide and Phenylalanine Applications; [Traubenwachstum und biochemische Eigenschaften der Tafeltraubensorte ‘Trakya Ilkeren’ (V. vinifera L.) nach Vorernte-Behandlungen mit verschiedenen Konzentrationen von Wasserstoffperoxid und Phenylalanin]

Uneven grape ripening, leading to decreases economic valued of grapes is one of the main problems faced by grape growers in early table grape growing. In recent years, there has been increasing concern about improving of fruit quality in fruit crops. Among the various quality improvement methods, different types of foliar compounds are used for this purpose and hydrogen peroxide (H2O2) and phenylalanine (Phe) can be given as examples to some of these chemicals. This research was carried out during the 2015 growing season by using early ripening table grape cv. Trakya Ilkeren. In the study, it was assessed that how different doses of hydrogen peroxide (0, 10, 20 and 40 mM) and phenylalanine (0, 1, 2 and 4 mM) affected physical and biochemical properties of cv. Trakya Ilkeren. In terms of physical properties, doses of hydrogen peroxide and phenylalanine had only significant effects on grape firmness and cluster length. The best results were obtained from 4 mM Phe application (6.76 N) in grape firmness and were obtained from applications of 10, 20 and 40 mM H2O2 (23.66, 23.86 and 23.99 cm) and applications of 1, 2, and 4 mM Phe (23.95, 24.46 and 24.88 cm) in cluster length. However, most of biochemical properties were considerably affected by doses of hydrogen peroxide and phenylalanine except for juice pH and p-value. It was recorded that the highest total phenolic compounds contents varied from 3571.28 (10 mM H2O2) to 3871.22 mg GAE kg−1 fw (40 mM H2O2) compared to 0 mM application (2591.48 mg GAE kg−1 fw). In terms of total anthocyanin content, the highest mean was recorded for 4 mM Phe application (330.56 mg GAE kg−1 fw) than 0 mM application (168.79 mg GAE kg−1 fw). As a result, 4 mM Phe application particularly improved the most of biochemical properties in cv. Trakya Ilkeren. © 2018, Springer-Verlag GmbH Deutschland, ein Teil von Springer Nature.