Two field experiments were conducted in a sandy soil in the extension field in El-Salhia region, Sharkia Governorate during 2004/2005 and 2005/2006 seasons to study the effect of three levels of nitrogen (45, 65 and 85 kg N/fad) and three glycinebetaine rates (0, 8 and 12mM/fad) on the growth and yield of barley (Giza 124 cv.) under two irrigation intervals (weekly irrigated and di-weekly irrigated). The most important findings could be summarized as follows: Irrigation every two weeks instead of one week reduced significantly all growth attributes. The relative decrease percentages were 25.41 and 22.93%, 22.63 and 19.98%, and 25.11 and 26.19% for flag leaf blade area, total chlorophyll and relative water content in both seasons, respectively. Addition of 85 kg N/fad increased these traits by 12.80 and 13.63%, 1.88 and 3.50%, and 3.28 and 4.59% in the first and second seasons, respectively compared with the addition of 45 kg N/fad. Meanwhile, using 12 mM glycinebetaine (GB) increased these traits by 20.63 and 23.06%, 32.30 and 35.80%, and 22.57 and 30.40% in the first and second seasons, respectively compared with untreated plants. Under stress or non stress condition, increasing N level from 45 to 85 kg/fad without GB did not increase total chlorophyll. Meanwhile, this trait was increased significantly with increasing GB from zero to 12 mM. Prolonging the period of irrigation from 7 to 14 day reduced significantly the yield and its attributes. The relative reduction percentages for grain and straw yields were 22.73 and 26.02% and 26.73 and 24.79% in both seasons, respectively. Increasing N-level from 45 kg to 85 kg N/fad increased grain yield, straw yield and mean productivity by 12.84 and 12.78%, 16.43 and 14.7%, and 12.88 and 12.85% in both seasons, respectively. Meanwhile, the relative increase percentages due to application of 12mM GB/fad compared with zero GB were 21.27 and 24.77%, 24.82 and 26.83%, and 21.30 and 24.73% for these traits in both seasons, respectively. The interaction between frequent irrigation, zero GB and 45 kg N/fad gave 11.38 ardab/fad compared with 15.34 ardab/fad which was obtained from frequent irrigation, 8mM GB/fad and 85 kg N/fad. Meanwhile, the interaction between drought condition, zero GB and 45 kg N/fad gave 8.66 ardab/fad compared with 11.69 ardab/fad which was obtained from drought condition, 8mM GB/fad and 85 kg N/fad treatments.

Two field experiments were carried out at a private farm at Manchat Nabhan, Fakose, Sharkia Governorate, Egypt during 2017/18 and 2018/19 winter seasons. The study aimed to find out the effect of five exogenous application levels of AsA and H 2 O 2 (S0: without, S1:100 ppm AsA, S2: 200ppm AsA, S3: 30mM H 2 O 2 and S4: 60mM H 2 O 2 ) on wheat (Triticum asetivum, L. cv.Misr 1) under three treatments of irrigation water (4, 5 and 6 irrigations) using surface irrigation system. A randomized complete block split plot design with three replicates was used in each season. The irrigation treatments and the levels of AsA and H 2 O 2 were randomly allocated in the main and sub-plots, respectively. The most important findings could be summarized as follows: At 105 days from planting, wheat plants under water stress (irrigation four times) without AsA and H 2 O 2 application showed a significant decrease in leaf area index (LAI), relative water content (RWC %) and total chlorophyll in comparison to wheat plants under well watered in both seasons. In general, the highest values of these traits were significantly gained from the highest concentration of ascorbic acid (200 ppm) and H 2 O 2 (60mM) in both seasons. At maturity, in both seasons, irrigations 4 times significantly resulted in lower spikes number m -2 , 1000-grain weight and grain yields than those in the plots irrigated 6 times. Generally, the maximum values of these traits were significantly obtained from the highest levels of ascorbic acid and H 2 O 2 in both seasons. Under stressed and unstressed plants, increasing AsA and H 2 O 2 levels significantly improved all these traits.

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Two field experiments were conducted in a new soil conditions in the extension field in El Qantra-West, Ismailia Governorate, Egypt (30 0 58 / N, 32 0 23 / E, and 10m above mean sea level) during 2016 and 2017 summer seasons. The study aimed to find out the effect of five exogenous application levels of AsA and H 2 O 2 on yellow corn hybrid 352 (three way cross) under three amounts of irrigation water (1.00. 0.80 and 0.60 of the estimated crop evapotranspiration) using surface irrigation system. A randomized complete block split-plot design with three replications was used in each season. The irrigation treatments and the levels of AsA and H 2 O 2 were randomly allocated in the main and sub-plots, respectively. The most important findings could be summarized as follows: Irrigation by 2250 m 3 /fad (severe water stress) instead of 3750 m 3 /fad (full irrigation) reduced ear leaf blade area, total chlorophyll and relative water content in both seasons. Increasing the level of AsA up to 350ppm/fad increased ear leaf blade area, total chlorophyll and relative water content followed by the highest level of H 2 O 2 (60mM H 2 O 2 ). Decreasing irrigation water significantly reduced ear length, 100-grain weight and grain yield/fad. Meanwhile, ear length, 100-grain weight and grain yield/fad were significantly obtained from the highest level of AsA followed by the highest levels of H 2 O 2 compared with their untreated analogues. The interaction between the both studied factors showed that application of 350ppm AsA and 60mM H 2 O 2 treatments protected about 920 and 320 kg/fad grains from collapse under moderate water stress (3000 m 3 /fad). Meanwhile, under severe water stress, treatments by same levels of AsA and 30mM H 2 O 2 protected about 670 and 330kg/fad grains from lose. Application of 350ppm AsA saved approximately 750m 3 /fad of irrigation water without yield reduction.

Two field experiments were conducted in a sandy soil in the extension field in El-Kassasein, Ismailia Governorate, Egypt during 2007 and summer seasons. The work aimed to study the effect of five levels of glycinbetaine (0, 5, 10, 15, 20mM/fad) on the response of SC 10 maize hybrid to three rates of drip irrigation water (1.00. 0.80 and 0.60 of the estimated crop evapotranspiration, which represented 2625, 2100 and 1575 m 3 water/fad, respectively). The most important findings could be summarized as follows:Irrigation by 1575 m 3 /fad instead of 2625 m 3 /fad reduced significantly ear leaf blade area, total chlorophyll, relative water content and leaf water potential, except the content of GB in leaves which was significantly increased in both seasons. Meanwhile, increasing the level of glycinebetaine (GB) up to 15 mM/fad increased these traits and the content of GB in leaves compared with their untreated analogues.Decreasing the amount of irrigation water from 2625 to 1575 m 3 /fad reduced significantly the grain yield, protein yield and water use efficiency (IWUE). While, the relative increase percentages due to application of 15mM GB/fad compared with zero GB were 28. 47 and 25.30%, 54.53 and 47.25%, and 27.61 and 25.10% for these traits in both seasons, respectively.The interaction between both studied factors showed that under moderate water stress condition (2100 m 3 /fad) without GB addition the responses of these traits were only 11.59 and 10.77 ardab/fad, 135.29 412 ABD ALLA KOTB and 119.69 kg/fad and 0.773 and 0.718 kg m -3 compared with 14. 31 and 13.49 ardab/fad, 195.07 and 176.25 kg/fad and 0.954 and 0.899 kg m -3 when the concentration of GB was increased to 15mM GB/fad in both seasons, respectively.