الفهرس 
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Abstract
In order to enhance the growth, yield and chemical constituents of roselle plant under Sharkia Governorate conditions, a split-plot experiment was carried out during the two consecutive summer seasons of 2018 and 2019. The two experiments included two main factors where, the first factor which was four planting dates (15th April, 1st May, 15th May and 1st June), the second factor was five amino acid concentrations (control sprayed with tap water, tyrosine acid or/and glutamine acid) each at 100 or 200 ppm concentrations) as well as their interaction treatments. Following data were recorded: plant growth parameters, yield components as well as chemical constituents. Results revealed that roselle planted in 15th April produced tallest plants and more branches and leaves as well as heaviest leaf dry weight per plant compared to the other dates. Also, the early planting date (April 15) recorded the highest values of roselle yield components, nutrients content, total chlorophyll and anthocyanin content with significant differences and the other dates under study. Moreover, glutamine acid at 200 ppm concentration significantly enhanced plant growth, yield components and chemical constituents compared to the other concentrations in both seasons. In general, planting roselle seeds in 15th April combined with sprayed with 200 ppm glutamine four times per season appears to encourage growth and is sufficient for attaining the highest yielding of roselle plant under Sharkia Governorate conditions.