Abstract: As one of the important phytohormones in plants, gibberellin plays a great regulatory role in the whole growth and developmental stages of higher plants. Focusing on the problems of the wine grape cultivar Syrah (Vitis vinifera cv. Syrah) in Linfen, Shanxi such as too dense clusters and low phenolic contents, this study investigated the application of gibberellin to elongate the grape clusters. For this purpose, three different concentrations (3, 5 and 7 mg/L) of gibberellin were used to dip the clusters 15 and 20 days before flowering. After maturation, the contents and compositions of anthocyanins and nonanthocyanins in grape berries were analyzed. The results obtained were as follows: 1) Gibberellin treatment had a significant effects on cluster elongation and fruit ripening (P < 0.05); 2) The contents of individual anthocyanins and non-anthocyanin monophenols increased with gibberellin concentration. For each gibberellin concentration, the contents of individual anthocyanins in grapes with gibberellin treatment 20 days before flowering were higher than 15 days before flowering; 3) Among all treatments, dipping in 7 mg/L gibberellin solution 20 days before flowering was the most effective in significantly increasing the contents of most individual anthocyanins and non-anthocyanin monophenols (P < 0.05) and facilitating the accumulation of acylated anthocyanins and flavonoid compounds.

Key words: Syrah grapes, gibberellin, cluster elongation, non-anthocyanin monophenols, monomeric anthocyanins