This study was conducted to evaluate 21 bread wheat genotypes includes 13 Egyptian cultivars under normal (five irrigations) and reduced irrigation (only the establishment irrigation) during 2010/11 and 2011/12 wheat growing seasons. The studied characters were: number of days to heading and maturity, grain filling period and rate, plant height, number of spikes m^-2, number of kernels per spike, kernel weight, grain yield, biological yield, straw yield, harvest index and stress susceptibility index. The variances due to genotypes were significant for all characters under all conditions and were higher under normal irrigation compared with those resulted from reduced irrigation for most characters across the two seasons, reflecting sufficient genetic variability between these entries, better expression of genetic potential and the importance of selection based on nonstress environment. Significant variations were detected due to water regimes, genotypes and interactions between genotypes and water regimes for most characters. The mean squares of irrigation regimes explained most of the total variations for most characters in the two seasons, indicating the relative importance of irrigation treatments in breeding programs for water stress tolerance. The variances due to genotypes were higher than those of interactions between genotypes and water regimes for most characters. The means of all genotypes significantly decreased for most characters in the two seasons under reduced irrigation. Number of spikes m^-2 and harvest index were the most and least affected characters by reduced irrigation in the two seasons, respectively. Line 1, Line 2 and Line 3 were the earliest genotypes for days to heading and maturity and could be used as a source of earliness in breeding program. There were manifested declines in the temperature during the second season than the first one, resulting in lower mean squares of genotypes and higher means of all genotypes in the second season in most cases. The average reduction for all characters tended to increase under the second season for most characters. Regardless the yield potentiality, Cham 4 then Sakha 93 were the most tolerant genotypes to water stress in the two seasons and could be used as source of water stress tolerance in breeding programs, while Gemmeiza 9 was vice versa. Sakha 94 had high yield potential and water stress tolerance and hence recommended to be used as parent for genetic analysis and improvement of water stress tolerance in wheat breeding programs. Misr 1, Misr 2, Sids 13 and Shandweel 1 showed the high yield potentiality and susceptibility to water stress and could be used as source for yield potential improvement only. Sids 12 in the two seasons showed low yield potential and susceptibility to water stress. The remaining genotypes had year-to-year variation in grain yield potentiality and stress susceptibility index. Generally, some water stress tolerant-genotypes under this study are not necessarily to be the highest in yield potentiality.