The effect of drought stress on yield and its components was studied on six (6) Iranian commercial corn hybrids at the Khorasan Razavi Agricultural Research and Natural Resources Institute Mashhad, Iran in 2010. The study was conducted in a randomized complete block design with three replications under drought stress conditions. There were significant differences among hybrids for all traits except plant height, ear height and upper leaves number, which demonstrated existence of high diversity among hybrids studied for drought tolerance. Among all hybrids, KSC704 (5.13 ton/ha) had the highest and KSC700 (3.16 ton/ha) produced the lowest yields in stress conditions. Correlation coefficients between the studied variables and total yield showed that only kernel no./row and 10 ear weight were significantly positive correlated with total yield under drought condition. We also used cluster analysis (Ward’s method) based on all investigated traits and grain yield under drought stress conditions to classify different hybrids in three groups with low intra-group and high extra-group similarities.

Key words: Corn, commercial hybrid, correlation coefficient, cluster analysis.