This study was conducted during two successive seasons on Jaffa orange trees (Citrus sinensis, Osbeck) grown in the Experimental farm at FacuIty of Agric., Moshtohor, Qalubia Governorate as atempt to improve the productivity and fruit quality by using yeast extract and/or promalin (BA + GA 4+7) applications.
Thus, foliar spray with yeast extract at 100 and 200 ml/L, promalin at 25 and 50 ppm and their combinations between, beside water spray as control were applied 2 times viz.: the first spray was at full bloom stage (i.e., April15th 2004 and April 18 th 2005) during 1st and 2nd seasons, respectively. While, the second spray was after two weeks from the first one. The randomized complete block design with 3 replications was used for arranging these nine spray treatments and evaluating their influence on the following measurements:
1- cropping indication (fruit set %; fruit drop%, fruit retention%; fruit creasing% and yield Kg/tree); 2-fruit quality i.e., both physical (weight, volume, dimensions, juice volume, rind thickness and no. of seeds per fruit) and chemical properties (TSS %, acidity, T.S.S./ acid ratio and Vitamin C content); 3- leaf N, P, K, Ca, Fe, Mn and Zn contents and leaf photosynthetic pigments content during both seasons of study.
Obtained data revealed that all cropping and fruit quality measurements positively responded to all applied yeast extract and promalin treatments compared with the control, except creasing pecentage, acidity percentage and number of seeds per fruit, the treatments were reduced them . Yeast extract at 200 ml/L + promalin at 50 ppm treatment surpassed statistically other treatments. In addition, all applied yeast extract and promalin treatments increased leaf N, P, K,Ca, Fe,Mn and Zn contents as well as leaf photosynthetic pigments content compared with the control. Also, Yeast extract at 200 ml/L + promalin at 50 ppm treatment gave the highest values in this respect.
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