Effects of Ethephon, Ethanol, Brassinosteroid and Leaf Pruning on Quantitative and Qualitative Characteristics of Yaghooti Siyah Grape Cultivar under Darab Environmental Conditions

Yaghooti is the earliest-maturing grape cultivar in Iran that is mostly grow in warm regions. In these regions berries do not have complete pigmentation and uniform color and this reduces marketability of fruits. The aim of this study was to investigate the effects of Ethephon (150 and 300 mgl-1), Ethanol (5 and 10%), Brassinosteroid (0.5 and 1 mgl-1) and defoliation (5 to 6 leaves around the clusters) on pigmentation and some quantitative and qualitative characteristics of Yaghooti Siyah grape berries. The experiment was carried out in a randomized complete block design with four replications and a 7-years-old vine in each replication during two consecutive years and two regions (Jannatshahr and Fasarood) of Darad. Based on the results, treatments had no effect on the chemical properties of fruit juices such as TSS, TA and TSS/TA. Although ethephon (300 mgl-1) significantly increased cluster weight compared to the control, other physical properties of berries and clusters were not affected by treatments. Treatments had not also effect on the color indicators such as CIRG, chroma, and Hunter components (L *, a * and b *). Anthocyanin and total phenolics concentration and antioxidant activity of fruit juice were not significantly different from those of the control. The results of the present study showed that the use of ethephon, ethanol and brassinosteroid in conventional concentrations can not improve the quantitative and qualitative properties and improvement of berries color, and it seems that in areas like Darab, high temperature during berry ripening and coloration period can be an important factor in color development and ripening process of fruit in Yaghooti Siyah grape.