The objective of the present study was to determine the mechanisms of tolerance of two corn (Zea mays
L.) genotypes (S¸ afak and Ant-I˙90) to water stress under five different irrigation treatments designated
as full irrigation (I100) with no water stress and slight (I75), mild (I50), severe water stress (I25) and no
irrigation (I0) treatments. The results showed that different irrigation levels applied has statistically
significant effect on yield components such as anthesis–silking interval, plant height, ear diameter, ear
length, kernel number and 1000 grain weight, except for ear number. In both of the genotypes, water
deficit stress significantly (P
≤
0.01) increased glucose, fructose, and sucrose contents while it decreased
protein content. The maximum grain yield was obtained from S¸ afak genotype under full irrigation, slight,
mild, severe and full water deficit stress as much as 9.35 t ha−1, 8.34 t ha−1, 7.89 t ha−1, 5.56 t ha−1 and
3.63 t ha−1, respectively. The highest water use was observed in I100 treatment as 738.1 mm for S¸ afak
genotype, while the lowest was found in I0 treatment as 260.0 mm for Ant-I˙90 genotype. The highest
water use efficiency was found in I50 as 15.7 kg ha−1mm−1 for S¸ afak genotype, and the lowest one was
found in I0 as 5.5 kg ha−1mm−1 for Ant-I˙90. It was concluded that S¸ afak was more tolerant genotype to
water stress than that of Ant-I˙90.