Comparison of commercial and new corn hybrids (Zea maize L.) under drought stress and normal irrigation conditions

In order to study and compare the effect of drought stress on morphological characteristics, yield and yield components of 28 new (resistant to heat and drought stress) and 6 commercial hybrids (as control) of corn, an experiment was carried out based on CRD with three replications under normal irrigation (50% allowed depletion of soil moisture) and drought stress (80% allowed depletion of soil moisture) conditions in Khorasan Razavi Agricultural Research and Natural Resources Center, Mashhad, Iran in 2009. Results showed that KSC500 hybrid had the greatest seed yield under normal irrigation, while N.11 hybrid demonstrated the greatest seed yield under drought stress condition. Results of orthogonal comparisons between commercial and new hybrids under normal conditions showed that there were significant differences for all studied traits except flag leaf length, tassel length, number of leaves, average number of corncob, cob weight, kernel weight, length and diameter of corncob. Under stress conditions, there were significant differences between these two groups of hybrids only for plant height, number of kernel rows per cob, total number of kernels per cob, cob diameter, kernel depth, cob percentage and total kernel yield. Results showed that in drought sensitive hybrids, seed yield components are affected and determine crop limitations in seed production.