Application of Glycine, Folic Acid, and Moringa Extract as Bio-stimulants for Enhancing the Production of ‘Flame Seedless’ Grape Cultivar

In this study, 130 uniform ‘Flame Seedless’ grape trees were selected for and subjected to the same cultural practices. The trees were sprayed three times, before flowering, during full bloom, and three weeks later with the following treatments: control (water only), 250, 500, and 750 ppm glycine; 50, 100, and 150 ppm folic acid (FA); 2%, 4%, and 6% leaf moringa aqueous extract (MLAE); and their combinations. High-performance liquid chromatography (HPLC) analysis of moringa leaf aqueous extract (MLAE) showed the presence of the phenolic compounds ellagic acid, vanillic acid, p-hydroxy benzoic acid, catechol, and gallic acid with values of 54.18, 18.79, 14, 12.32, and 12.12 mg/100 g, respectively. The obtained results showed that the foliar spraying of 250, 500, and 750 ppm glycine, 4% and 6% MLAE, and their combinations of glycine 500 ppm + FA 100 ppm + MLAE 4% and glycine 750 ppm + FA 150 ppm + MLAE 6% significantly increased the shoot length, shoot thickness, leaf chlorophyll content, yield, and fruit quality over the control. Glycine at 750 ppm was the best treatment followed by glycine at 500 ppm compared with the other applied treatments and the control in both experimental seasons.