Response of Washington Navel Orange Trees to Calcium Chloride Foliar Application

Document Type : Original Article


Thirteen-year-old Washington navel orange (Citrus sinensis L. Osbeck) trees grown in a private citrus orchard at Wady El-Mullak region, Abo-Hamad district, Sharkia Governorate were sprayed during 2012 and 2013 seasons with calcium chloride (CaCl2) at 0.5, 1.0 and 2.0 % and water as control treatment when the fruits reached pea size (5 mm in diameter). The experimental trees were sprayed 6 times at the first and mid of May, June, October months during both seasons to investigate their influence on fruit drop and fruit retention percentages, as well as yield and fruit quality.
Spraying CaCl
2 at 1.0 % gave the maximum fruit retention percentage, number of fruits and yield/ tree, but reduced June and pre-harvest fruit drop percentages. Fruits juice of trees sprayed with CaCl2 at 0.5 and 1.0 % contained the highest TSS and the lowest total acidity percentages and consequently the highest TSS/ acid ratio compared with those sprayed with 2.0 % CaCl2 and water (control). Moreover, calcium chloride spraying at 1.0 % was the optimum treatment for improving fruit quality and enhancing the yield/ tree.