Глобальный журнал биологии, сельского хозяйства и медицинских наук

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Physiological Studies on Improving Fruit Quality of valencia Orange Fruits

Abd El-Rahman, G.F. & Hoda, M.Mohamed

Optimum fruit size is one of the most important parameters determining the profitability of citrus production to acquire high marketing value. The study was conducted on valencia orange trees (Citrus sinensis, L) budded on sour orange rootstock (Citrus aurantium). Trees were planted at 5x5 m spacing (168 trees/ feddan) in clay soil under flood irrigation and growing in a private orchard, located at El kalubia governorate, Egypt. The study involved two experiments. First experiment was done in season, (2012 and 2013) to estimate fruit growth rate from mid May, 2012 (30 day after full bloom) to mid March, 2013. Obtained results indicated that, fruit growth rate passes through three stages. First stage (cell division) up to in mid-June, second stage (cell division and elongation) up to in mid-August and third one (slightly cell elongation) which continued until harvest time. Second experiment was done in (2013/2014) and (2014/2015) seasons to determine the effects of foliar nutritional sprays on fruit quality, yield and leaf mineral content. Trees were either left untreated or had foliar applications of monopotassium phosphate (MKP) at 1% and 2%, dipotassium phosphate (DKP) at 1% and 2% and active bread yeast at 40 and 80 ppm. Trees were sprayed by all treatments at full bloom stage then were divided into two groups the first was sprayed by the same treatments in mid June and the second was sprayed in mid August. Obtained results indicated that, (DKP) at 1% was the best treatment for increasing fruit quality, yield and leaf mineral content followed in a descending order by (MKP) at 2% and active bread yeast at 40ppm. Foliar sprays trees in mid-June resulted in the best results than mid- August treatment.