الفهرس 
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Abstract
A two years study was carried out during two successive seasons of 2017 and 2018 on seven years old Early Sweet grapevines .cv. grafted on Freedom and/or Salt creek rootstocks grown in sandy loam soil, spaced at 2 X 3 meters apart under drip irrigation system in a private grapevines orchard located at Cairo-Alexandria desert road about 50 km from Cairo, Egypt.
The main objective is to study the effect of nitrogen supported with potassium and two rootstocks as well as their combinations on vegetative growth parameters, leaf petiole nutrients content, yield and fruit quality properties of Early Sweet grapevine.cv.
The study was a factorial experiment, hence two rootstocks i.e. Freedom and Salt creek they occupied main plot Whereas, seven rates of both actual nitrogen and actual potassium as soil application located in the sub plots as follow:
T1: 30kg N/fed.+45kg k/fed. (1:1.5 ratio)
T2: 30kg N/fed.+60kg k/fed. (1:2 ratio)
T3: 40kg N/fed.+ 60kg k/fed. (1:1.5 ratio)
T4: 40kg N/fed.+80kg K/fed. (1:2 ratio)
T5: 50kg N/fed.+75kg k/fed. (1:1.5 ratio)
T6: 50kg N/fed.+100kg K/fed. (1:2 ratio)
T7: 60kg N/fed.+120kg k/fed. (Control)
Actual nitrogen and potassium soil application were added at three times, first (25% of nitrogen+ potassium) was added at 15th February, second (50% of nitrogen+ potassium) was added at 1st April and third (25% of nitrogen+ potassium) was added at 1st June in both seasons.
The obtained of results could be summarized as follow:
5.1. Factor A: nitrogen and potassium fertilization levels :
5.1.1. Effect of nitrogen and potassium fertilization level on vegetative growth of parameters.
Vines fertilized with 60N+120K kg/feddan (T7) gave the highest values of shoot length, number of leaves per shoot and weight of annual pruning per vine in both seasons.
Results of the effect of nitrogen and potassium fertilization level on vegetative growth of grapevine indicated, in the first season:
Vines fertilized with 40N+80K kg/feddan (T4) gave the highest positive effect on final buds burst percentage.
Vines fertilized with 50N+100K kg/feddan (T6) gave the highest values of vegetative buds percentage.
Vines fertilized with 50N+75K kg/feddan (T5) gave the highest values of buds fertility coefficient percentage
Vines fertilized with 40N+60K kg/feddan (T3) gave the highest values of fruitful buds percentage.
Results of the effect of nitrogen and potassium fertilization level on vegetative growth of grapevine indicated, in the second season that:
Vines fertilized with 50N+100K kg/feddan (T6) gave the highest values of final buds burst percentage.
Vines fertilized with 40N+60K kg/feddan (T3) gave the highest values of vegetative buds percentage .
Vines fertilized with 30N+45K kg/feddan (T1), 30N+60K kg/feddan (T2) and 40N+80K kg/feddan (T4) gave similar and high positive effect in increasing buds fertility coefficient percentage.
Vines fertilized with 40N+80K kg/feddan (T4) proved to be the most effective treatment in increasing fruitful buds percentage .
5.1.2. Effect of nitrogen and potassium fertilization level on cluster characteristics and yield:
Results of the effect of nitrogen and potassium fertilization level on Cluster characteristics and yield showed, in the first season that :
Vines fertilized with 50N+750K kg/feddan (T5) gave the highest values of cluster weight.
Vines fertilized with 40N+80K kg/feddan (T4) surpassed other treatments in increasing yield per vine.
Results of the effect of nitrogen and potassium fertilization level on Cluster characteristics and yield showed, in the second season that :
Vines fertilized with 30N+60K kg/feddan (T2) gave the highest values of cluster weight.
Vines fertilized with 60N+120K kg/feddan (T7) proved to be the most effective treatment in enhancing vine productivity.
Furthermore, vines fertilized with 40N+80K kg/feddan (T4) gave the highest positive effect on number of clusters per vine in both seasons.
5.1.3. Effect of nitrogen and potassium fertilization level on fruit quality:
Results of the effect of nitrogen and potassium fertilization level on fruit quality indicated, in the first season that :
Vine fertilized with 40N+80K kg/feddan (T4) gave the high positive effect on berry firmness, fruit width and fruit TSS/acid ratio.
Vines fertilized with 50N+75K kg/feddan (T5) gave the highest values of berry adherence strength and high reduction in number of shot berries.
Vines fertilized with 40N+60 K kg/feddan (T3) surpassed other treatments in enhancing fruit length.
Vines fertilized with 30N+ 60Kkg/feddan (T3) and 40N+ 80Kkg/feddan (T4) gave the highest reduction effect in acidity
Vines fertilized with different nitrogen and potassium treatments failed to induce any positive effect on TSS (%).
Results of the effect of nitrogen and potassium fertilization level on fruit quality indicated, in the second season that :
Vines fertilized with 50N+75K kg/feddan (T5), 50N+100K kg/feddan (T6) and 60N+120 K kg/feddan (T7) gave similar and high positive effect on berry firmness.
Vines fertilized with 40N+80K kg/feddan (T4), 50N+75K kg/feddan (T5) and 50N+100K kg/feddan (T6) proved to be the superior treatment in reducing number of shot berries.
Vines fertilized with 30N+60K kg/feddan (T2) produced longer fruits and increased cluster width as compared with other treatments.
Vines fertilized with 30N+45K kg/feddan (T1) and 40N+80K kg/feddan (T4) succeeded in enhancing fruit content of total soluble solids than other treatment.
All treatments failed to induce any significant effect on berry adherence strength, acidity % and fruit TSS/acid ratio.
5.1.4. Effect of nitrogen and potassium fertilization level on leaf petiole nutrients content:
Results of the effect of nitrogen and potassium fertilization level on leaf petiole nutrients content indicated, in the first season that :
Vines fertilized with 60N+120K kg/feddan (T7) induced the highest positive effect on petiole nitrogen content.
Vines fertilized with 50N+100K kg/feddan (T6) induced the highest positive effect on phosphorus content of petiole.
Data present that ”Freedom” rootstock induced a positive effect on potassium concentration than ”Salt Creek” rootstock. The treatment 60N+100k kg/feddan (T7) proved to be the superior treatments in this concern in increased potassium concentration in both seasons. The interaction between two factors showed that in the first season, combinations of both ”Salt Creek” rootstock and ”Freedom” rootstock fertilized with 60N + 100 K kg/feddan (T7) Vines fertilized with 40N+80K kg/feddan (T4), 50N+75K kg/feddan (T5) and 60N+120K kg/feddan (T7) gave similar and high positive effect on petiole calcium content.
Vines fertilized with 40N+80K kg/feddan (T4) and 60N+120K kg/feddan (T7) gave similar and high positive effect on iron content.
Vines fertilized with 30N+45K kg/feddan (T1) 40N+60K kg/feddan (T3) and 40N+80K kg/feddan (T4) induce high positive effect on zinc content.
Vines fertilized with 30N+60K kg/feddan (T2) gave the highest manganese content of petiole.
All vines fertilized with nitrogen plus potassium induce high positive effect on copper content of petiole excepted vines fertilized with 50N+75 K kg/feddan (T5) gave the lowest values of copper content.
All vines fertilized with nitrogen plus potassium had no significant effect on boron content of petiole.
Results of the effect of nitrogen and potassium fertilization level on leaf petiole nutrients content indicated, in the second season that :
Vines fertilized with 50N+100K kg/feddan (T6) and 60N+120K kg/feddan (T7) gave the highest values of petiole nitrogen content.
Vines fertilized with 40N+60K kg/feddan (T3) exerted high values of phosphorus content in leaf petiole.
”Freedom” rootstock fertilized with 60N + 100 K kg/feddan (T7) exerted the highest positive effect on potassium concentration of petiole than other combinations in this concern.
Vines fertilized with 40N+80K kg/feddan (T4) and 50N+75K kg/feddan (T5) gave similar and the highest values of calcium content of petiole.
Vines fertilized with 50N+100K kg/feddan (T6) gave the highest values of magnesium content of petiole
Vine fertilizes with 40N+80K kg/feddan (T4) proved to be the superior treatment for increasing Fe content in leaf petiole.
All treatments of fertilization nitrogen plus potassium failed to induce any significant effect on zinc content of petiole.
Vines fertilized with 40N+80K kg/feddan (T4) and 50N+100K kg/feddan (T6) gave similar and high positive effect on manganese content of petiole.
Vines fertilized with 40N+60K kg/feddan (T3) and 40N+80K kg/feddan (T4) gave similar and high positive effect on copper content of petiole than other treatments.
Vines fertilized with 40N+60K kg/fedan (T3) proved to be the superior treatment reducing boron content of leaf petiole.
Furthermore, vines fertilized with 60N+120K kg/feddan (T7) proved to be the superior treatments in increasing leaf petiole potassium content in both seasons.