Annual and seasonal pattern of precipitation in Iran is characterized by unpredictable fluctuations, bringing about are a great deal of uncertainty towards receiving sufficient rainfall for agricultural production. This study was aimed at evaluating the impact of different moisture regimes on growth, chlorophyll fluorescence, yield and its attributes in corn hybrids grown in 2006. The experiment was conducted at Lavark Research Farm of the Isfahan University of Technology, using a 3-replicate split plot RCBD. Irrigation regime, in which four levels of evaporation from a Standard LAI was significantly affected by irrigation and hybrids. I 1 with 5.43 and I 4 with 3.66 and S.C.700 with 4.93 and T.C.647 with 3.85 produced the highest and lowest LAI, respectively. While hybrids differed significantly in their F m at both 10-leaf and tasseling, irrigation regimes differed significantly (p 0.05) only in their F v /F m at tasseling. Plant phenology was significantly affected by hybrids, S.C.500 (1634 GDD) and S.C.704 (1733 GDD) proved earliest and latest amongst hybrids studied in our experiment. Grain yield was significantly affected by irrigation regime and hybrid. The I 1 (12340 kg ha -1 ) out- performed (by 37%) the I 4 (7670 kg ha -1 ) due, apparently, to a greater seed/ear (35%) and 1000-seed weight (8%) with former irrigation regime. S.C.700 (11220 kg ha -1 ) out-yielded S.C.500 due to its greater (11%) 1000 seed weight. With conditions in which current experiment conducted, seed/ear (0.75 ** ) and 1000-seed weight (0.45 ** ) were the most and the least correlated attributes to grain yield. I 4 with lowest biological (16650 kg ha -1 ) and grain yields indicated the smallest irrigation water use efficiency both for biological (1.42 kg m -3 ) and grain (0.99 kg m -3 ) yield, compared to the rest of the regimes. S.C.700 produced a higher biological yield amongst hybrids used in this experiment.
