الفهرس 
Seasonal changes in fruit qualityOnly 14 pages are availabe for public view
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Abstract
The present study was carried out during 1972/1973 and 1973/1974 on Valencia orange trees grown in El-Tahreer Province t o study the effect of folia sprays w i t h Ethrel and 2,4,5-T a t concentrations of 20, 50 and 100 ppm at two spraying dates on yield, regreening percentag, f r u i t quality and rind pigments. The results could be summarized in the following points: 1. Foliar sprays w i t h Ethrel and 2,4,5-T had no effect on yield (as number of f r u i t s and f r u i t weight (kg) per tree) in. both season^^ 2. The percentage of regreening of Valancia orange trees was significantly reduced by Ethrel treatments and it was obvious in the early preharvest spray applications than that in late applications in both seasons. 3 . In the f i r s t season, the percentage of regreening was significantly reduced by early preharvest sprays of 2,4,5-T a t 20 and 50 ppm than that of the control. In the second season, early prehakivest sprays of 2,4,5-T had no effect on the percentage of regreening. Moreover, l a t e preharvest sprays, generally increased the percentage of regreening in both seasons of the present study. 4. As the season advanced, f r u i t weight and size increased, while f r u i t diameter and height, rind percentage and juice volume were nearly constant. 5. Spraying with both Ethrel and 2,4,5-T generally increased f r u i t weight and size i n the two seasons and the significant difference was only found between the 100 ppm and the control as early sprays, Late sprays with Ethrel had no effect on f r u i t size, and significant differences were only found be tween 2,4,5-T at 20 alrd 100 ppm and the control in the f i r s t season. 6. Spraying with Ethrel and 2,4,5-T had no apparent effect on f r u i t dimensions, rind percentage and juice v olume. 7. Concsrning the seasonal changes in the chemical characters, TSS, TS~/acid r a t i o and total carotenoids increased. On the other hand, the per cent acidity, vitamin C content, chlorophyll a and chlorophyll b decreased.8. Spraying with both Ethrel and 2,4,5-T had no effect on the percentage of TSS in the f i r s t season, while in the second season, early sprays of 2,4,5 -T a t concentrations of 50 and 100 ppm increased the TSS values. 9- Ethrel sprays had no effect of the per cent acidity, while 2,4,5-T sprays generally reduced the per cent acidity in the two seasons.