الفهرس 
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Abstract
The goal of this study was elucidating the effect of some nutrients, plant extracts, selenium and silicon on vegetative growth aspects, tree nutritional status, yield and fruit quality of Ewaise mango trees grown under Upper Egypt conditions.
During the three seasons, the following parameters were recorded:
1. Vegetative growth characteristics namely length and thickness of spring growth cycle shoot, number of leaves / shoot and leaf area (cm)2.
2. Leaf chemical components namely chlorophylls a & b, total chlorophylls and total carotenoids (mg/ g F.W) and percentages of N, P, K and Mg (on dry weight basis).
3. Percentages of initial fruit setting and fruit retention.
4. Yield/ tree expressed in weight (kg.) and number of fruits/ tree.
5. Some physical and chemical characteristics of the fruits namely weight (g), height, diameter and thickness (cm.) of fruit, pulp weight%, T.S.S.%, total, reducing and non- reducing sugars %, total acidity (as g citric acid/ 100 ml juice), vitamin C content (as mg/ 100 ml juice) and total fibre%.
The nearly same obtained data during the three seasons could be summarized under the following main topics:
1- Vegetative growth aspects
The four growth aspects namely length and thickness of shoot, number of leaves/shoot and leaf area in the spring growth cycle was positively affected by treating the trees thrice with nutrients (N, P, K, Mg, Zn, Fe, Mn, Cu and B) alone or in combinations with any plant extracts (oils of nigella, moringa, onion and garlic each at 1% and extracts of green tea and turmeric each at 0.05%), selenium at 5 ppm or silicon at 50 ppm relative to the control treatments. The best plant extracts in stimulating these growth aspects, in descending order were turmeric extract, oils of garlic, onion, moringa, nigella and green tea extract. Using selenium and or silicon was favourable than using plant extracts with nutrients. The maximum values were recorded on the trees that received all nutrients, selenium and silicon, together.
2. Leaf chemical components
Treating the trees with nutrients alone or in combined with any plant extracts, selenium and silicon resulted in enhancing chlorophylls a & b, total chlorophylls, total carotenoids, N, P, K and Mg in the leaves relative to the check treatment. The best plant extract in this respect was turmeric extract. Trees treated with all nutrients, selenium and silicon had the highest values.
3. Percentages of initial fruit setting and fruit retention
Percentages of initial fruit setting and fruit retention were remarkably improved in response to treating the trees with nutrients alone or in combination with plant extracts, selenium and silicon rather than non-application. Using silicon and/or selenium had an obvious promotion on the two parameters than using plant extracts. The maximum values were recorded on the trees that received nutrients, selenium and silicon together.
4- Yield:
Yield/tree expressed in weight (kg.) and number of fruits/ tree was clearly improved due to treating the trees with nutrients either alone or in combined with any plant extracts, selenium or silicon compared to the control treatment. The promotion was associated with using turmeric extract, oils of garlic, onion, moringa, nigella and green tea extract, in descending order. Treating the trees with all nutrients plus selenium and silicon gave the maximum values.
5- Fruit quality:
It was remarkably enhanced in terms of increasing weight, height, diameter and thickness of fruit, fruit pulp%, T.S.S.%, total, reducing and non–reducing sugars % and vitamin C content and decreasing total acidity % and total fibre % in the fruits relative to the control treatment in response to exposing the trees to nutrients alone or in combined with any plant extracts, selenium and silicon relative to the control. Using plant extracts, selenium or silicon with different nutrients was superior to using nutrients alone in improving fruit quality. The best results were realized on the trees that received all nutrients, selenium and silicon together.