To study the effects of different irrigation regimes on vegetative and reproducitve development of corn (Zea mays, L.),hybrid S.C. 704, an experiment was conducted in Experimental farm of College of Agriculture, Isfahan University of Technology in 1987. The irrigation treatments were: 11= irrigation after 70 mm, 12= irrigation after 100 mm, 13= irrigation after 160 mm evaporation from Class A pan. The design was complete randomized blocks with four replicates.
The results showed that grain yield of Ii is significantly greater than 12 and 13• Lesser kernels per ear and smaller kernels in 13 caused 37% reduction in grain yield with respect to I. Smaller ears in I. caused reduction of kernel number and redution of leaf area index and leaf area thickness caused smaller kernels to form.
The effect of three irrigation regimes on harvest index was not significant, and this index was about 0.51. Water use efficiency for grain yield and biological yield-of I. was less than 12 and 13 On the average, 1.04 Kg of grain and 2.09 Kg of biological yield was obtained with 1.0 m3 of water?
Leaf dry weight, stem weight, and total aerial part of I was less than and I2• Also, depth of maximum root density and horizontal root development in I was significantly more than I. and 12• But, maximum root depth in 13 was less tan I. and I.,. In general, irrigation of corn after 70 mm evaporation from Class A pan seems to e suitable Isfahan region.
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