Effect of Water Deficit on the Productivity of Four Bread Wheat Cultivars under Calcareous Soil Conditions in Egypt

Irrigation reduction is the main problem facing wheat production especially in calcareous soil in Egypt. Four bread wheat cultivars (Giza 171, Shandaweel 1, Sids 14 and Sakha 95) were studied under 100 %, 60 % and 40 % of full irrigation in calcareous soil conditions. Three irrigation treatments were distributed in the horizontal strips, and the four bread wheat cultivars were distributed in vertical strip. Results showed that full irrigation (100%) which used 2476 and 2357 m 3 /fed in the in the first and second season, produced the highest values of all studied traits, followed by irrigation treatment 60% then irrigation with 40% of full irrigation. Data cleared the superiority of Sakha 95 in grain, biological yield and harvest index percentage. Moreover, Sakha 95 was the best cultivar under all irrigation treatments. On the other hand, the worst cultivar was Sids 14 for grain and biological yield. Genotype by environment interaction (GGE) Biplot analysis revealed that Shandaweel 1 was the most stable cultivar regardless of its grain yield. Meanwhile, Sakha 95 was the most superiority cultivar with moderate tolerance to reduced irrigation. On the contrary, Sids 14 had reasonable stability and was the worst cultivar for grain yield. Moreover, Giza 171 was the most unstable cultivar under these conditions. Irrigation water productivity (IWP) values increased with increasing water deficit for all wheat cultivars. The highest IWP values were 2.90 and 3.10 kg/m 3 in first and second season by using water stress treatment 40% from full irrigation with Sakha 95, respectively. While, the lowest values were 1.14 and 1.41 kg/m 3 were obtained from Sids 14 with 100% irrigation treatment in the first and second season, respectively. The study recommends cultivation of the cultivar Saka 95 under reduced irrigation in the calcareous soil.