This investigation was carried out on Picual olive trees during the two successive seasons of 2022 and 2023 at Matrouh Governorate, Egypt. The purpose of this study is to evaluate the  effect of glycine betaine, glutathione, and chitosan foliar sprays on improving vegetative growth characteristics, blooming, yield properties, and fruit physical and chemical properties of Picual olive trees under a rain-fed production system.  The results indicated that foliar spray of glycine betaine at 50, 100 ppm, and glutathione at 50 and 100 ppm are suggested to increase yield and quality. With  higher percentages of flowering , perfect flowers, initial and final fruit set increase productivity. Also , they ameliorated fruit's physical properties (fruit weight, length & diameter, flesh weight & flesh dry matter ) and fruit oil content.  Application of chitosan at 10 g/l produced less fruit oil content while having the same impact on increasing fruit yield and quality. However , chitosan at 2.5 g/l and control trees exhibited low yield and fruit physical and chemical properties under the rain-fed conditions in both seasons, respectively. According to the data, proline and glycine accumulation and plant stress are positively correlated, which reinforces the idea that quantitative measurement of proline and glycine is used as an indicator of stress sensitivity and the extent of its relationship to physical and chemical characteristics.