Improving Capacity of Yellow Corn Tolerance to Water Stress by Foliar Application of Ascorbic Acid and Hydrogen Peroxide

Two field experiments were conducted in a new soil conditions in the extension field in El Qantra- West, Ismailia Governorate, Egypt (30⁰ 58^/ N, 32⁰ 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 H₂O₂ 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 H₂O₂ were randomly allocated in the main and sub-plots, respectively. The most important findings could be summarized as follows: Irrigation by 2250 m³/fad (severe water stress) instead of 3750 m³/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 H₂O₂ (60mM H₂O₂). 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 H₂O₂ compared with their untreated analogues. The interaction between the both studied factors showed that application of 350ppm AsA and 60mM H₂O₂ treatments protected about 920 and 320 kg/fad grains from collapse under moderate water stress (3000 m³/fad). Meanwhile, under severe water stress, treatments by same levels of AsA and 30mM H₂O₂ protected about 670 and 330kg/fad grains from lose. Application of 350ppm AsA saved approximately 750m³/fad of irrigation water without yield reduction.