The Effect of Spraying Gibberellin , Urea and Zinc on The Growth and Yield of Orange Trees (Citrus sinensis L) Grown in Salah Adin Governorate

Abstract

This study has been made in one of the private Citrus orchards in Salahddin province Tikrit district/ Alam during 2012 Season, this study was made on Citrussinensis L this for study the impact of spraying Gibberellin which its concentration 20 mg liter 1- and the Urea 0.05% and zinc ( zinc sulfate 0.5%) regarding the growing properties on the local orange tree, the experiment was designed according to Randomized Complete Block Design (R.C.B.D), the experiment comprised of 8 treatments repeated three times and distributed randomly over three sectors, The trees have been treatment until they went wet till the morning time on 10/4 and 10/5 for the season 2012 at the flowering stage and after four weeks the trees have been sprayed for the third time by Urea only on the date 30/September /2012.The results showed that the impact of spraying with GA3 and Urea and Zinc on the trees individually and together was positive to increase the percentage of the cluster of the yields and the rest of the yields and it was positive to reduce the percentage of the falling yield measured with the compared treatment and they gave better results of these properties and the percentage of the juice in the yield and the percentage of the yields reached (29.08 , 16.95 , 4.86) % consecutively, and it led to increase the content of the leaves of chlorophyll and the leave area completely measured with the compared treatment. The treatment of (GA3+N+ Zn( was exceeding by giving the highest averages for these properties if they reach (58.95) spad unit and 5.27m2 per a tree convectively. and led to increase and the length of their fields and their diameter and their weight and size and the thickness of peel and the treatment of comparison which has been the lowest records and this increase has reached the top of the treatment (GA3+N+ Zn( and it reached 32.76kgm per tree1-, 8,25 cm, 6.97cm, 138,86g, 129.41 cm3 consecutively. also it led to increase the percentage of the juice and the whole percentage of the Sugars measured with the compared treatments and the treatments were different namely when GA3 and Urea and Zinc were involved and they gave better results of these properties and the percentage of the juice in the yield and the percentage of the Sugars reached (49.14 , 9.93) consecutively.