Soil Environ. 39(1): 38-49, 2020 DOI:10.25252/SE/2020/132078 Online ISSN: 2075-1141 Print ISSN: 2074-9546 *Email: mto252000@yahoo.com © 2020, Soil Science Society of Pakistan (http://www.sss-pakistan.org) Seed treatment for improving wheat productivity under deficit irrigation conditions in arid environment AbdAllah Mohamed El-Sanatawy 1 and Abdel Tawab Metwally Zedan 2 1 Department of Agronomy, Faculty of Agriculture, Zagazig University, Egypt 2 Department of Agricultural Engineering, Faculty of Agriculture, Zagazig University, Egypt [Received: January 19, 2020 Accepted: April 14, 2020 Published Online: April 16, 2020] Abstract Climate change and frequent drought events in arid regions present challenges for crop production and food security in many parts of the world. Objectives of the present research were to enhance wheat plant tolerance to water stress by applying regulated irrigation deficit scheme and treating seeds with drought-tolerant substances. A field experiment was carried out to study the impact of three irrigation levels (severe, moderate, and full irrigation) and three seed treatments [control , soaking in salicylic acid (SAA), and soaking in ascorbic acid (ASA)] on yield and its attributes and water use efficiency (WUE) of wheat. Moderate water stress significantly decreased total photosynthetic pigments, grain number/spike, spike number/m 2 and grain yield, however, amounts of water saving by this deficit irrigation rate suggested a feasible option for wheat production in water limited environments without unacceptable yield reduction. Treating seeds with SAA or ASA significantly increased total photosynthetic pigments, relative water content, recovery efficiency, grain number/spike and grain yield compared with untreated seeds. The efficacy of deficit irrigation was increased by treating seeds with SAA which was demonstrated by the increased grain number/spike, grain yield/ha and WUE compared to untreated seeds. These results suggest beneficial effects of drought-tolerant substances on enhancing plants’ ability to mitigate the negat ive water stress impacts. Keywords: Deficit irrigation, seed treatment, ascorbic acid, salicylic acid, WUE, recovery efficiency Introduction Globally, water availability has become an issue in recent years (Smakhtin et al. 2004). The Mediterranean region is in prospect to undergo increases in drought occurrences (Robredo et al. 2007). Hoerling et al. (2012) added that the Mediterranean region has suffered from the change of winter Mediterranean precipitation towards drier conditions which occurred due to region’s sensitivity to regular global ocean warming; therefore, Mansour et al. (2017) pronounced that crop production was influenced critically by water limitations in arid and semi-arid regions, like Egypt. Bread wheat (Triticum aestivum L.) is the most prominent strategic crop in Egypt. Egyptian daily nutritional requirements depend on bread wheat for more than thousands of years. Wheat water requirements are expected to increase by 9% in North Egypt (the Nile Delta) and 18% in both Middle and Upper Egypt in 2040 (Ouda et al., 2016). Irrigation with less than full crop water requirements termed as deficit irrigation (Attia et al. 2015), can be considered a chance to save water resources. Understanding the physiological, biochemical, and ecological obstructions related to drought stress is very important for better management (Fahad et al. 2017). Over-synthesis of reactive oxygen species occurs in plant cells due to water deficit stress (Zhu, 2000). The increased reactive oxygen species levels lead to various cellular mechanisms that result in damage and death of the cell (Ishikawa et al. 2009). Many studies for the influence of water deficit on wheat grain yield and water use efficiency concluded that the grain yield could be largely maintained, while substantial reduction in irrigation volume could be used (Zhang and Oweis, 1999; Abdelraouf et al. 2013; Said, 2016; Said and Abd El-Moneem 2016). Salicylic acid (SAA) is an endogenous growth regulator that belongs to the phenol group that is operative in different plant processes, particularly related to photosynthesis and water relations (Khan et al. 2003 and El-Shafey 2017). Salicylic acid plays an important role in enhancing plant resistance to biotic and abiotic stresses (El Tayeb and Ahmed, 2010; Ding and Ding, 2020). Ascorbic acid (ASA) plays a vital role in regulating cell cycle and in several essential processes of plant growth and development (El-Shafey, 2017) and protecting plant cells against reactive oxygen species effects (Smirnoff, 2000).