The Role of Some Growth Stimuli on Mango Growth Performance

: Mango ( Mangifera indica L.) is one of the most important fruit crops. The present experiment was carried out during 2020- 2021 seasons, in order to study the effect of some growth stimuli on growth behavior, nutritional status and productivity of 10-year old Keitt mango trees grown in sandy soil at a private orchard, Badr city, El-Beheira governorate, Egypt. The treatments were the control (untreated trees), chitosan at 30, 60 and 90 ppm, spermidine at 5, 10 and 20 ppm, vermicomposting leachate (VLC) at 10, 15, and 20% and potassium silicate at 400, 500 and 600 ppm and sprayed four times a month before flowering, at the beginning of flowering, at full bloom and three weeks after the contract. The obtained results showed that, all treatments caused an improve in traits under study, the highest values of the number of flowering panicle (353.3 and 352.3), the number of hermaphrodites/ panicle (695 and 696.6), hermaphrodites flowers (46 and 45.6 %), fruit set (18.4 and 18.6 %) and the number of fruits / tree (128 and 127) were obtained by 5 ppm spermidine, in the two seasons also followed by the lowest concentration of chitosan (30 ppm). The highest value of total yield was obtained by 5 ppm (70 and 71.6 kg/ tree,) and 10 ppm (67.6 and 66.3 kg/tree) concentrations of spermidine also followed by the lowest concentration of chitosan (30 ppm) in 2020 and 2021. The highest values of fruit weight (556.3 and 557.3 g.), vitamin C content (50 and 52 mg/ 100 ml juice) and leaf K content (3.3 and 3.3 % resp.) were obtained by 600 ppm potassium silicate treatment. In the meantime, the highest value of fruit TSS (%), total sugars (%) and leaf N and P content was obtained by potassium silicate at 600 ppm and VCL at 20 % treatments. As for acidity (%), the highest values were recorded when using the three concentrations of spermidine (5, 10 and 20 ppm) compared to the control, while the lowest values were obtained by using the highest concentration of VCL (20%) and potassium silicate (600 ppm) (0.20 and 0.22 %) for the two treatments, resp., in the two seasons.