A field experiment, in a split-split plot design with three replications, was conducted, during 2009/2010 growing season in semi arid region Mogran belongs Zaghouan governorate, to evaluate the response of eleven bread wheat (Triticum aestivum L.) genotypes under four water stress treatments (T0: rainfall, T1: rainfall + 10 mm, T2: rainfall + 20 mm, T3: rainfall + 30 mm applied at each stage). The evaluation was based on eight agro-morphological traits: flag leaf area (FLA), plant height (PH), spike length (SL), spikelet number/spike (SN/S), 1000 kernel weight (TKW), grain yield/spike (GY/S), root length (RL) and root volume (RV). Variance analysis revealed a high significant (p<0.01) effect of water treatments and genotypes for all traits except spikelet number/spike. Water supply had a positive effect on yield and yield related traits. In fact, greatest values were obtained under T3 for PH, SL, SN/S, TKW and GY/S. Accession 10 gave the highest spikelet number/ spike, 1000 kernel weight and grain yield/spike which appeared to be the most drought tolerant genotype. Grain yield/spike was significantly and positively correlated with PH (r = 0.25), SL (r = 0.32), SN/S (r = 0.75), and TKW (r = 0.88) which indicated that effective selection can be done on these traits through breeding programs.
