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Ain Shams University (2018)

RESPONSE OF KEITT MANGO TREES TO DIFFERENT NITROGEN AND POTASSIUM FERTILIZATION LEVELS UNDER SHADING AND NON SHADING CONDITIONS

Emam, Ola Abd El Satar Abd El Haliem.

Titre : RESPONSE OF KEITT MANGO TREES TO DIFFERENT NITROGEN AND POTASSIUM FERTILIZATION LEVELS UNDER SHADING AND NON SHADING CONDITIONS

Auteur : Emam, Ola Abd El Satar Abd El Haliem.

Etablissement de soutenance : Ain Shams University

Grade : Doctor of Philosophy (PhD) in Agricultural Science 2018

Résumé
The present experiment was conducted during the three successive seasons of 2011, 2012 and 2013, at a private orchard located at Cairo-Alexandria desert road (km. 76 Cairo – Alex). The aim of this experiment was to study the response of Keitt mango trees to different nitrogen and potassium fertilization levels under shading and non-shading conditions. The obtained results could be summarized as follows : Shade treatments on growth and chemical composition of Keitt Mango Trees : Vegetative growth : 1. The significantly highest values of trees height increment percentage, leaf area and dry mater percentage were found under shading condition compared to those under open field condition in all studied seasons. 2. Trunk diameter increment percentage and chlorophyll content under screenhouse condition were significantly higher compared to those on open field condition in all seasons except third season. Chemical characteristics Leaf mineral content 3. The screenhouse condition recorded higher nitrogen percent in leaves more than open field condition, except, first season. 4. Growing mango under screenhouse gave the highest content of potassium, sulfur, iron, zinc, manganese, copper and cobalt in leaves for the three seasons. 5. Trees under shading condition significantly recorded highest leaf magnesium and calcium percentage compared to those on open field condition in the second season only. Flowering characteristics 6. They bloom dates were always earlier inside the screenhouse than outside the open field during the three studied seasons. 7. Treatment shading condition manifested highest significant value of number of panicle and panicle longer compared to those under open field condition for all studied seasons. Fruiting 8. Trees under screenhouse net led to significant increase in initial number of fruit set / panicle and number of fruits retained / panicle during the three seasons gained highest fruit set compared to trees grown under open field condition. 9. Trees under shading achieved the least value of fruit DROP percentage during all studied seasons. 10. Trees under shading achieved the highest value of fruit retention percentage during all studied seasons. 11. The number of fruits/tree and yield were significantly affected by applied screenhouse treatment compared with open filed treatment during the three growing seasons. Fruit characteristics 12. Highest values of fruit weight and fruit volume found with screenhouse compared to those under open field condition in three tested seasons. 13. The application of shading condition led to significant increase in fruit width during first and second season only. 14. Mango trees cultivated under screenhouse condition gave the higher values for pulp weight and pulp thickness than the open field condition. These results were true in three growing seasons. Fruit chemical characteristics 15. Trees under shading condition significantly recorded highest nitrogen, iron, zinic, magnesium, sulfur and copper in fruits pulp compared to those on open field conditions. 16. The screenhouse treatment increased mango fruits pulp from potassium and calcium percent more than open field treatment in the first and third seasons, respectively. No significant influence was found in second season. 17. Trees under shading condition significantly recorded highest phosphorus percentage in fruits pulp compared to those on open field conditions except for first season. 18. The application of shading condition increased mango fruits pulp from manganese percent more than open field treatment in first and second seasons, respectively, no significant influence was found in third season. 19. Trees under shading condition significantly recorded highest total soluble solids and total acidity in fruits value compared to those on open field conditions except for second season. 20. The screenhouse condition produced higher fruits content from ascorbic acid, total sugars and reducing sugars more than open filed condition through three growing seasons. 21. Trees under shading condition achieved higher significant value of total phenol, crude fiber content and moisture percentage in fruits pulp than those under open field conditions. 22. The screenhouse treatment had no significant influences on dry mater percentage fruit all over the tested growing seasons, except second season. Hormonal content in February 23. The screenhouse net recorded lowest ABA content in buds compared with open field conditions. 24. The bud content of zeatin and benzyl adenine hormone in buds were higher at screenhouse treatment than other treatment. Hormonal content in October 25. The screenhouse condition lead to increase the zeatin and benzyl adenine content in buds compared with open field condition.

Présentation étendue (EULC)

Page publiée le 10 mars 2019