Effect of Salicylic and Ascorbic Acids Foliar Application on Picual Olive Trees Growth under Water Stress Condition

The present study was conducted during the 2018 and 2019 seasons on 5 years of Picual olive trees (Oleaeuropaea L.), grown in calcareous soil at the farm of the Faculty of Desert and Environmental Agriculture, Fuka, Matrouh governorate, Egypt. The main objective was to investigate the effect of foliar application with salicylic acid (SA) (100, and 150mg/L), and ascorbic acid (AA) (50, and 100mg/L) under water stress conditions (rain-fed, 50 and 100 % of crop evapotranspiration (ETc) on growth, physiological characteristics, yield, and fruit quality. The results showed that the highest value of leaf area, shoot length, and yield (kg/tree) were recorded with the treatment salicylic acid (150 mg /L) in both seasons compared with the control. The ascorbic acid at 100 mg/L recorded the highest leaf chlorophyll content and maximum fruit quality compared with the control. Also, sprayed with salicylic acid 100 mg/L and Ascorbic acid at 100 mg/L gave the highest response for leaf content of N, P, K, Ca and Mg (%) compared to other treatments. In addition, 150 mg/L salicylic acid treatment showed the highest value for relative water content associated with the lowest value of leaf proline content compared with control. There were no significant differences between 100% ETc, and 50% ETc irrigation treatment in the presence of salicylic acid 150 mg L or ascorbic acid 100 mg L for enhancing most ofthe studied characteristics.Finally, spraying Picual olive trees with salicylic and ascorbic acids had a positive impact on trees growth, yield, and fruit quality under stress conditions compared to rain-fed treatment in both seasons.