2Faculty of Agriculture, University of Birjand, Iran.
Drought is one of the major problems affecting crops production, including corn, in many parts of Iran. In order to detect drought tolerant grain corn hybrids, an experiment with twenty corn hybrids was conducted during 2006 in Qom Province, Iran, using a complete randomized block design with four replications, under optimal moisture and drought stress condition. Results showed diversity among hybrids in response to moisture conditions. BC504 and BC652 produced the highest yields and BC678 and NS504 produced the lowest yields under optimal and stress conditions, respectively. Assessing hybrids according to some selection indices lead to introduce BC504, BC652, BC404, KSC302, KSC320 and KSC647 as drought tolerant ones. It seems likely that Stress Tolerance Index, Geometric Mean Productivity, and Harmonic Mean indices, which showed the highest correlation with grain yield under both optimal and stress conditions, can be used as the best indices for maize breeding programs to introduce drought tolerant hybrids.