This investigation was carried out during two consecutive seasons (2016 and 2017) in a private farm at EL-Sadat region, Menoufia Governorate, Egypt, to study the effect of foliar application with phenylalanine, putrescine and sea algae extract on vegetative growth aspects, nutritional status, yield and fruit quality attributes of Keitt mango cultivar. All trees were six years old, spaced at 2 x 3 meters apart, grown in sandy soil and irrigated by the drip irrigation system.
Ten treatments were applied as follows: foliar application with phenylalanine at (100, 200 and 400ppm), Putrescine at (125, 250 and 500ppm) and sea algae extract at (0.5, 1.0 and 1.5%) in additionally control treatment. All foliar application treatments were carried out through the three times: the beginning of spring growth flush (the first week of March), the full bloom (the first week of April) and just after fruit setting (the third week of May).
The results revealed that all application substances at high doses significantly outperformed the use of medium and low doses of each. However, foliar spraying with phenylalanine at 400ppm, putrescine at 500ppm and sea algae extract at 1.5% had the best results in terms of ensuring the best vegetative growth traits, increasing leaf mineral content, achieving the highest yield with its components and improving the physical and chemical characteristics of fruits of Keitt mango trees.