Jawa Daoud ^(1)*, Rashid Khrboutly ⁽¹⁾  and Amjad Badran ⁽²⁾

(1). Department of Horticulture. Faculty of Agriculture. Tishreen University. Lattakia . Syria.

(2) Agricultural Scientific Research Center .Lattakia.Syria.

(* Corresponding author: Email: daoudjawa@gmail.com (0938477016)).

Received: 17/05/2020                                              Accepted: 06/07/2020

Abstract

The current study was conducted during the two seasons (2018 And 2019).on Diospyros kaki var (Hachyia).  Which grown at Boqa Botanical Research Center,Faculityof Agriculture, Tishreen  University , Lattakia. In order to assess the effects of different levels of fertilization treatments and the spraying of gibberellic acid on the productivity of Japanese persimmon trees.This study included the use of three levels of chemical fertilization (NPK) and comparison with the treatment of farmers and the presence of a control treatment without the addition of any fertilizer in addition to spraying trees with a solution of gibberellic acid GA3 concentration (25) ppm.This search was carried out according to  complete randomize block design which included (5) treatments: Control treatment, farmer treatment (500 g K2O + 500 g P2O5 + 500 g N), low fertilizing treatment (400 g K2O + 300 g P2O5 + 400 g N), medium fertilizing treatment (600 g K2O + 450 g P2O5 + 600 g) N and high fertilization treatment (800 g K2O + 600 g P2O5 + 800 g N) in addition to the use of organic fertilizing by (25) kg per tree for the previous four traitments. Each treatment included (3) repeats and each repeat included (3) trees .thus the number of trees that  used in the experiment (45) trees. Fertilization treatment and the spray of gibberellic acid (25) Ppm led to increase the fruit setting and tree production, as there is the highest percentage in the fruit setting in the high fertilization treatment, wich reached (67.42)%. Also, the highest tree production was found in the high and medium fertilization treatments, which reached to (31.93) kg. / The tree and (29.87) kg / tree, respectively, without significant differences between these two treatments, also contributed to improving the quality of the fruits either in terms of the average weight of the fruit or its content of ( total acidity –  total sugars – Total soluble solids – vitamin C) where the average fruit weight in the treatment of high fertilization reached (154.09) g while  The weight of the fruit in the witness treatment trees didn’t exceed (136.85) g. As for the chemical content of the fruits, the results of the statistical analysis indicated the superiority of the high and medium fertilization coefficients without significant differences between them, as the high and medium fertilization fruit levels from acidity reached (0.362) and (0.354) % compared to the witness which reached (0.235%). The fruit content of high and medium fertilization of sugars reached (16.74) and (15.81) %, respectively, between them, compared to the witness which reached (11.57) %. The fruit content of total dissolved solids amounted to (18.32) and (18.30) %, respectively, without significant differences between them compared to the witness which percentage was (14.06%). As for vitamin C), the results of the statistical analysis indicated the superiority of treatment The control of most of the studied treatments was vitamin C in the control of the control (43.72) mg/100g

Keywords: Diosoyros kaki, Fertilization, Gibberellic acid, Production, Quality

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