In this study, chemical and bio-control agents were  evaluated for their efficiency to control of  citrus fruit-rot disease  caused Alternaria citri  (K2) both, in vitro and in vivo trials. The most effective fungicides were score, montro and Iprodione compared with other fungicides depend on Ec50 and Ec90. While, the fungicide Pyraclostrobine had moderate effect on linear growth of A.  citri. Meanwhile, the Coprax, Coprareekh and Azoxystrobine were the least effective fungicide at Ec90.  Trichoderma harzianum and Bacillus subtilis tested showed antagonistic action effect to a highly pathogenic isolate of Alternaria citri, with different degrees of inhibition. T. harzianum was the most effective compared with B. subtilis, in vitro trials. Also, all fungicides were evaluated on incidence of citrus fruit rot disease in vivo trials.  The disease incidence was reduced, but with different degrees. In addition, using T. harzianum, B. subtilis, B. megaterium (Bio-ARC) and Trichoderma   album (Bio-Zeid) decreased    incidence of citrus fruit rot disease. On the other side, T. harzianum showed the highest suppressive effect against citrus fruit rot pathogen. Generally, all tested fungicides and bio-agents were effective against the causal fungus in vitro and in vivo trials, but with different degrees.

Wady El Natroun high way (Beer Hooker Area) in a private orchard in a sandy soil under drip irrigation system with saline water.  in 2015 and 2016 seasons. Chinese tangerine (Citrus tangerine) transplant were budded on three rootstocks namely sour orange (Citrus aurantum, mion), volkamer lemon (Citrus volkameriana, Tem) and X639 hybrid between (Cleopatra mandarin × Ponicurus trifoliata) grown under saline conditions to study the effect of foliar  application of antioxidants namely ascorbic and salicylic acid on vegetative growth and leaf mineral contents. Results showed that, Volkamer lemon rootstock surpassed sour orange and x639 rootstocks under saline conditions, the highest incremental percentage young tree height, stem diameter, number of leaves per shoot and leaf area were registered by Chinese tangarine scion budded on Volkamer lemon rootstock. Among selected antioxidants ascorbic acid at the concentrations of 800 ppm recorded the highest significant values for vegetative growth parameters and surpassed salicylic acid. Also Chinese mandarin scion budded on volkamer lemon accumulated the highest concentrations of nitrogen (N), phosphorus(P), magnesium(Mg), and chloride (Cl-) and the lowest concentration of sodium (Na+). Chinese mandarin scion budded on sour orange rootstock accumulated the highest concentrations of potassium (K) while Chinese tangerine scion budded on x639 accumulated the highest concentrations of sodium (Na).

Nodal stem segments of in vitro growing somatic embyogenesis and seedling-derived plantlets of sweet orange, C. sinensis (L.) of (Washington navel, shamouti and blood orange cvs.); grapefruit, C. paradisi (L.); Local mandarin, C. deliciosa (Tenor); lemon, C. limon; (L.); citron, C. medica (L.); lime, C. aurantifolia (Christm); rough lemon, C. jambhiri (Lush) and sour orange, C. aurantium (L.) were cultured on MS medium supplemented with different concentrations of BA (0.5,1.0 and 2.0 mg/L) alone or in combination with NAA (0.5 mg/L) for shoot multiplica-tion. The results indicated that somatic embryogenesis-derived plantlets can be suc-cessfully propagated in vitro with a good vigor compared with germinated seedlings. A large number of proliferated shoots were produced when these explants were cul-tured on MS medium containing 0.5mg/L of BA combined with 0.5mg/L of NAA. Most obtained shoots were rooted on half-strength MS medium containing 0.5 mg/L of NAA. These in vitro grown plantlets were then successfully transferred to green house through acclimatization process.

The experiments were conducted in two suc-cessive seasons (2004 - 2005) on Washington Na-vel orange fruits to study the effect of cold storage conditions on reducing postharvest losses and im-proving keeping quality for the export mar-ket.Fruit samples were obtained from El–Fayoum governorate, Egypt and treated with vapor gard (VG) 2%, calcium chloride (CaCl2) 4% or vapor gard 2% + calcium chloride 4%. Fruits were stored at 2 or 8 ºC for 60 days and the last group was stored at 2 ºC for 30 days and transferred to be stored at 8ºC for another 30 days at R.H. 85-90%.The results revealed that during storage fruits treated with Vapor gard (2%) alone or with calci-um chloride (4%) + Vapor gard (2%) had been in good quality as well as it caused a pronounced increase in peel color and fruit firmness, while fruit weight loss and juice percentage were de-creased. In addition, it caused a significant in-crease in ascorbic acid, total sugar and calcium concentration, but there is no significant effect in T.S.S. / acid ratio. While, free amino acid, total soluble phenols and free proline concentrations were decreased. Furthermore, the fruits storaged at 2º + 8ºC caused a pronounced increase in fruit firmness, while fruit weight losses, juice percent-age and peel color were decreased. Also, it caused a pronounced decrease in T.S.S. / acid ratio, total sugar, total free amino acid, total soluble phenols and free proline concentrations, but there is no significant effect on calcium concentration. In addition, there is an increase in ascorbic acid con-centration. Generally, the results revealed that Vapor gard either alone or combired with calcium chloride dipping treatments and stored at 2º + 8ºC had better results in improving fruit quality and decreasing total fruit losses compared with control or calcium chloride treatment alone at other stor-age temperatures and this was also accompanied by changes in various metabolic and physiological processes of orange fruits.