The current investigation was executed to assess the effects of magnetization, which combines magnetized water (MW) and magnetic iron (150g tree -1 ), and organic acids (Humic acid at 150cm tree -1 ) As anti-salinity factors in mitigating the negative effects of salinity on growth, leaf mineral contents, yield and fruit properties of Washington Navel orange trees planted in sandy soil and watered with drip irrigation method (ECw of irrigation water = 4ds/m) in 2014 and 2015 under El-Behera governorate conditions. The results indicated that the trees subjected to combination treatment involved (MW) and humic acid as soil application or magnetic iron gave the best vegetative growth parameters (tree height, canopy volume, No. of shoots per branch, shoot length, No. of leaves shoot and leaf area compared to comparative treatment (the control). Soil application of humic acid under irrigation with MW(MW+ Humic acid) increased mineral contents for leaves (N, P, K, and Mg) meanwhile, the sequence of MW+ magnetic iron gave the highest Ca content. The highest leaf Na content (0.48 and 0.52%) obtained by the control meanwhile, the lowest leaf proline content (10.0 and 9.2mg g -1 ) was obtained by combination treatment (MW + humic acid) compared to the highest values (12.4 and 12.7mg g -1 ) recorded with the control (WW). Yield and fruit quality attributes were increased with soil application of humic acid or magnetic iron following irrigation with magnetized water.

Due to the limited water resources, it is necessary to study the best ways to reduce the use of irrigation water, increase the efficiency of water use without affecting the growth of trees and maintain the production of citrus productivity under these circumstances. Afield experiment was conducted during 2015 and 2016 seasons at El-Nubaria region, Beheira Governorate to investigate the effect of three irrigation water regimes (100, 75 and 50% of actual irrigation practiced in the orchard) and soil application of hydrogel (50 and 100g/tree) and organic plant residues (3.5 and 6.5kg/tree) as chemical and natural water absorbing soil amendments on growth, yield and water use efficiency on ''Washington Navel'' orange trees grown on a sandy soil under drip irrigation system. The obtained results point out that, applied organic plant residues at rate 6.5 kg/tree or 100g/tree hydrogel under moderate irrigation rate (T5 and T3) significantly increased the most growth parameters (canopy volume, number of shoots/branch and leaf area) , fruit set, leaf relative water content and decrease fruit drop%. Moderate irrigation rate + 100g/tree hydrogel (T3) and control (T1) were the best treatments in increasing leaf N,P,K andCa contents. The highest yield (78.8 and78.47) and (80.36 and 79.06 kg/tree) was obtained by T3 and T5 in 2015 and 2016 seasons, respectively. All treatments increased water use efficiency especially T9 (5.64 and 5.46 kg/m 3 ) compared with the control which recorded the lowest values (3.16 and 2.93 kg/m 3 ). Control (T1) followed by T3 and T5 tended to improve the physical fruit properties meanwhile T8 and T9 increased the most of chemical fruit quality. The lowest fruit splitting% (6.58 and 5.87 %) coated with T3 and T5. Soil microorganisms content and dehydrogenase activity were increased under moderate irrigation rate + 3.5 or 6.5 organic plant residues (T4 and T5) compared to the control (T1).

This work has been carried out to evaluate a new thornless strain of lime trees as compared with Mexican lime (local or Balady cultivar) planted at 5x5m and grown in clay soil at a private orchard at Kaferelsheikh Governorate during 2015 and 2016 seasons. The evaluation involved growth, flowering, seeds, yield and fruit parameters. The new strain revealed morphological characteristics distinct from the local cultivars but it had a small size of canopy which may be reflected in increasing the number of planted trees/ feddan. Fruits of the selected strain is distinguished by high percentage of juice acidity (7.2-8.2%), juice weight % (47.8-48.9%) over the local cultivar. Also, it was characterized as thornless trees with less seed number /fruit (2.06-2.23). DNA fingerprint was performed using RAPD technique for the molecular characterization. RAPD analyses exhibited a total of 42 bands with an average of 10.4 bands / primer when six primers were used. The polymorphism percentage (18%) was observed between the new strain and Mexican lime. The new lime strain is considered as a valuable genetic material for Egyptian citriculture industry.

The present investigation was carried out during the two successive growing seasons 2014 and 2015

The deficiency of irrigation water is a main factor of limiting the growth and production of fruit trees, particularly in arid and semi-arid areas regions. So this study was conducted in order to assess the influence of applying silicon in the nano form to minimize the negative effects caused by water stress. A field trial was behaved in 2016 and 2017 seasons at Beheira Governorate to study the effect of three rates of drip irrigation viz. high irrigation rate (control=100%) and two deficit irrigation regimes (75 and 50% from the control), foliar application of nano-silicon (0, 100, 200 and 300ppm) and their interaction on growth, yield and water relations of ''Washington Navel'' orange trees grown in sandy soil and irrigated by drip irrigation method. The findings showed that, deficit irrigation treatment (I 3 ) was related with reduced vegetative growth aspects (canopy volume, No. of shoots /branch, Shoot length) as well as stomatal resistance, however transpiration rate was increased in both seasons, in addition, nano-silicon spraying at 300 or 200ppm caused a significant increase in previous growth aspects over the control. The combination between high or moderate irrigation rate (I 1 or I 2 ) with nanosilicon spray at 300 ppm (S 4 ) were more effective in enhancing growth parameters. In both seasons, deficit irrigation treatment (I 1 ) decreased leaf mineral contents and increased leaf proline content. However, high concentration of nano-silicon markedly increased leaf mineral contents but reduced leaf proline contents. Both low and high irrigation rates (I 2 and I 3 ) or high concentration of nano-silicon (S 4 ) and their interaction achieved the highest values of bound water and osmotic pressure and the lowest values of total and free water contents. Furthermore, the yield and components, water use efficiency and most of external and internal fruit properties were significantly increased under moderate irrigation (I 2 ) or high concentration of nano-silicon and their interaction (I 2 x S 4 ), while, the percentage of fruit splitting was decreased. Finally, trees irrigated with moderate irrigation rate combined with nano-silicon at (300 ppm) enhancement the growth, yield and fruit properties. On the contrary decreased fruit splitting(%) and applied irrigation water by 25% , whereas, increased water use efficiency compared to high irrigation rate (control) without nano-silicon spray.