Alleviation of alternate bearing phenomenon in mango trees using boron and15n-tracer technique / Ahmed Salem Ali Ibrahim ; Supervised Ayman Elsayed Shaban , Elsayed Hassan Badawy , Rawia Abdelghany Elmotaium

Thesis (M.Sc.) - Cairo University - Faculty of Agriculture - Department of Pomology

This investigation was conducted during two successive seasons (2014/2015) and (2015/2016) using 15 years old productive mango (Mangifera indica) trees cv. Zebda. The trees were grown at Almalak valley farm, Elsharkeya governorate-Egypt (30-51o N; 32-53o E). Trees were planted 8x8 meters apart in sandy soil under drip irrigation system using the Nile water. Results show that the boron foliar application resulted in significant increase in flowering, fruit set and fruit yield. In addition, boron has improved fruit quality both physical (improve color, increase fruit number, reduce fruit weight, size and firmness) and chemical characteristics (increase total soluble solids, total sugars and vitamin C while reduce total acidity). The interaction treatment between boron and nitrogen gave the highest values for all tested parameters. Boron application resulted in improvement of mango tree nutritional status as leaf nitrogen, phosphorus and potassium concentration and leaf, bud and fruit boron concentration significantly increased. In addition boron application resulted in significant increase in leaf total chlorophyll, total carbohydrates, total sugars, C/N ratio and decrease in total phenol content. The interaction treatment of 250 mg.L-1 boron and 1500 g N/tree nitrogen is the best treatment which helps alleviate alternate bearing phenomenon and obtain the highest economic yield in the off-year

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