EFFECT OF SPRAYING WITH SOME ANTIOXIDANTS ON GROWTH, YIELD, FRUIT QUALITY AND NUTRITIONAL STATUS OF ‘NAVEL ORANGE᾿ TREES

Abstract

This study was carried out through two con-secutive seasons 2016 and 2017 to investigate the effect of spraying with some antioxidants on vege-tative growth, yield, fruit quality and nutritional sta-tus of twelve years old ‘Navel orange᾿ trees grafted on sour orange rootstock and grown in a private orange orchard in Qalubia Governorate, Egypt cultivated in a silty clay loam soil. This experiment involved three antioxidant materials named (salicyl-ic acid, citric acid and folic acid) and each one spraying by three levels of each of with (250, 500 and 1000 ppm) from each salicylic, citric and folic acid plus control treatment so the experiment in-cluded ten treatments. Selected trees were sprayed three times in March, in May in July by aqueous solution of salicylic acid, citric acid and folic acid until the point of runoff. The highest values of vegetative growth were obtained by spraying by 500 ppm salicylic acid, 1000 ppm citric acid and 500 ppm folic acid. Regarding to yield, results pointed out that the foliar spraying with 500 ppm salicylic acid, 500 ppm citric acid and 250 ppm folic acid gave the highest values of yield. Treatments of 500 ppm salicylic acid, 250 ppm citric acid and 250 ppm folic acid gave the highest values of physical and chemical fruit properties. In respect to nutrients content, the highest values of macronutrients were obtained by spraying of 250 ppm folic acid, while that spraying by 1000 ppm salicylic acid and 250 ppm folic acid gave the highest values of micronutrients. Therefore, using treatment 500 ppm salicylic acid may be recom-mended from economical point of view and as good treatment for enhancing Navel orange growth, yield, fruit quality and nutritional status especially under old citrus orchards.