اثرهاي ايزوپروپيل 2،4- دي كلروفتوكسي استيك اسيد و نفتالين استيك اسيد بر اندازه و جلوگيري از ريزش قبل از برداشت نارنگي محلي

Effect of 2,4-Dichlorophenoxyacetic Acid Isopropyl Ester and Naphthalene Acetic Acid on Fruit Drop, Size and Quality of Local Tangerine

An experiment was carried out to determine the effect of 2,4-D isopropyl ester and NAA on fruit size as well as preventing pre-harvest fruit drop of local tangerine in Jahrom. Seven year old trees of local tangerine were sprayed with aqueous solutions of 2, 4-D isopropyl ester at 0,4,8 and 12 mg/l 3, weeks after full bloom for improving fruit size. Highest yields and largest fruits were obtained in 12 mg/1 2,4-D treatment. Apart from reduced vit.C content other fruit characteristics were not affected. Pre-harvest fruit drop is a serious problem in Jahrom local cultivar of tangerine. Eight year old trees were sprayed with aqueous solutions of 2,4-D isopropyl ester at 0, 8, 16, 24 and NAA potassium salt at 15 and 30 mg/I on Dec. 21,1995 and Jan. 4, 1996. Spray treatment with NAA at a concentration of 30 mg/l reduced pre-harvest fruit drop by 56% as compared with the untreated control.