Inroduction The world faces one of the most critical challenges which it is the need to cover the food necessities of the melodramatically growing population. In last few years, wheat (Triticum aestivum L.) production did not met requirements of consumers and as a result of this the hunger and prices were increased worldwide. T WO field experiments were done at the Experimental Farm, Faculty of Agriculture, Menoufia University, Shebin El koom, Egypt, during 2015/2016 and 2016/2017 seasons, to

more »

... udy the response of growth, productivity and quality of four wheat cultivars (cvs.), i.e. Gemmeiza 12, Misr 3, Sakha 95 and Shandaweel 1 to three irrigation regimes, i.e. I 1 (five irrigations at tillering, stem elongation, booting, heading and ripening stages), as a control, I 2 (four irrigations with skipping one irrigation at ripening stage) and I 3 (three irrigations with skipping two irrigations at each of heading and ripening stages). The results showed that exposing wheat plants to drought stress by skipping two irrigations (I 3 regime) significantly decreased growth characters (plant height, flag leaf area, total chlorophyll and days from sowing to heading as well as maturity), grain yield components (no. of spikes/m 2 , spike length, no. of spikelets/spike, no. of grains/spikelet, no. of grains/spike, 1000 grain weight and grain weight/ spike), yields/fad (grain, straw and biological), translocation indices (crop and harvest indices) and grain yielding ability as well as grain quality (protein and carbohydrate yields/fad and carbohydrate percentage) compared to full irrigation treatment (I 1 regime). Reversely, protein percentage was significantly increased when the plants were exposed to skipping two irrigations at heading and ripening stages (I 3 regime). However, there are no significant differences between full irrigation (I 1 regime) and skipping one irrigation only at ripening stage (I 2 regime) for grain, straw, biological yields/fad and most related traits. Sakha 95 and Gemmeiza 1 2 cultivars were superior to the other cultivars in most traits over all tested irrigation regimes. However, Misr 3 and Shandaweel 1 cultivars had values of drought susceptibility index (DSI) less than one either at moderate (I 2 regime) or at severe drought stress (I 3 regime), indicating that such cultivars were relatively tolerant to drought stress compared to the other tested cultivars. The interaction between the two tested factors showed that the application of four irrigations (I 2 regime) to wheat cultivars namely Misr 3 and Shandaweel 1 are useful to save water consumption without significant reduction in wheat productivity.