Effects of Water Deficit on Grain Yield and Quality of Egyptian Bread Wheat Cultivars (Triticum aestivum L.).

Deficit of irrigation water is among the main abiotic stresses that affect grain yield and quality of bread wheat in newly reclaimed areas of Egypt as well as in arid and semi-arid regions of the world. Field experiments were conducted in the Experimental Farm of Damanhour University, El-Bostan, Egypt, to evaluate the effects of water deficit on yield and quality of the most common Egyptian bread wheat cultivars. Three water regimes; recommended irrigation (T₁), moderately stressed (T₂), severely stressed (T₃) were applied in two consecutive growing seasons. Water deficit significantly decreased yield and all of its components; number of spikes/m², number of grains/spike and kernel weight. Furthermore, water deficit negatively affected the flour extraction ratio, where percent flour was significantly and gradually decreased from T₁ to T₃; while, on the opposite side, fine bran (%) and coarse bran (%) were significantly and gradually increased with the declined water availability. Positive significant increase of grain total protein and each of dry and wet gluten contents were prominent with the progress of water deficit. Most of the quality properties determined by the Farinograph; i.e., water absorption and dough-stability time, were improved along the declined water availability with an exception of dough weakness which was negatively affected. Extensograph properties; i.e., dough resistance to extension and proportional number (dough resistance to extension/dough extensibility) were positively improved with the increased stress. Furthermore, the present results showed that the sensory properties of Shamy bread, prepared from stressed wheat flour, were slightly improved.