Effect of drought stress on yield and yield components on different forage cornhybrids

In order to study the effect of drought stress on yield on some new forage corn hybrids, an experiment was conducted at the experimental field of Seed and Plant Improvement Institute of Karaj, in 2009. The experiment was carried out using split-plot in a randomized complete block design (CRBD) with three replications. The main plots consisted of three levels of irrigation regimes (irrigation after 70, 100 and 130 mm cumulative evaporation from evaporation pan class A) and sub-plots included 14 new corn hybrids. In this experiment dry fodder yield per hectare, leaf number, leaf area index, ear dry weight, leaf dry weight, stem dry weight, plant height, measured and calculated. The results showed that hybrid differences in terms of dry matter yield, plant height at 5% probability level and in terms of leaf number, leaf area index, ear dry weight was significant at 1% probability level, while among the hybrids studied significant differences in terms of leaf dry weight was observed. Also, all the traits of drought stress and react to their difference in different stress levels and leaf number in 1% probability level was significant. Increase irrigation of normal irrigation severe stress decreases dry yield respectively 44% percent were.