تاثیر بر در خصوصیات کمی و کیفی پرتقال تامسون ناول روی پایه نارنج

Previous studies with tree species have demonstrated that foliar boron ( B ) promotes flowering , fruit set, and yield . However, for most species the optimum time for foliar B application has not determined.this investigation was undertaken to study the effects of time and rate of B application on sweet orange ( Citrus Sinensis (L. ) osbeck v.Thomson navel) tissue B concentration , yield, and quality. The experiment was conducted on Tomson navel orange on sour orange rootstock at Khoramabad research station ( north of Iran ) in randomised complete block design during three years . Were planted in north of Iran in 1978 at a spacing of 6 m .7m. The experiment consisted of 8 treatments were replicated 4 times making a total of 32 plots.the treatments were as follows: 1 ) control 2 ) 50 g Boric Acid /year /tree 3 ) 3000 mg/litr Boric Acid foliar spray in prebloom 4 ) 5000 mg/litr Boric foliar spray in prebloom 5 ) 3000 mg/litr Boric Acid foliar spray in postbloom 6 ) 5000 mg/litr Boric Acid foliar spray in postbloom 7 ) 3000 mg/litr Boric Acid foliar spray in prebloom and postbloom 8 ) 5000 mg/litr Boric Acid foliar spray in prebloom and postbloom . Boric Acid containing 21% B was applied with a handgun sprayer.The results indicated that difrent treatments did not show significant difference on fruit weight, diameter, length , total soluble solids, titrable acidity and yield while they had favorable effects on leaf B concentration.with foliar application at rate of 3000 mg/litr in one times and treatment with soil application at rate of 50 g /tree was more effective in increasing tissue B concentration, and decreased peel thickness.