Effect of Drought Stress on Some Morphological, Physiological and Agronomic Traits in Various Foliage Corn Hybrids

2 Abstract: In order to study the effect of drought stress on yield and some morphological and physiological traits in 14 new corn (Zea mays L.) forage hybrids, an experiment was designed. A split-plot layout within randomized complete block design with three replications was performed at Karaj Seed and Plant Improvement Institute Research farm in 2009. The main plots were three levels of irrigation; normal, mild stress and severe stress (irrigation after 70, 100 and 130 mm cumulative evaporation from Class A pan evaporation respectively,) and subplots included 14 hybrid corn. In this experiment, dry and fresh forage yield, number of leaves, leaf area index, leaf chlorophyll, ear dry weight, leaf dry weight, shoot dry weight, leaf to stem ratio (dry) and plant height were considered. The results showed significant difference for plant height, leaf to stem ratio (dry), dry forage yield hybrids (P<0.05) and the number of leaves, leaf area index, dry weight per ear (P<0.01), while among the studied hybrids no significant difference was observed for leaf dry weight and shoot dry weight. Also, all traits except number of leaves showed a significant difference (P<0.01) to drought stress. Increment of irrigation from normal to severe stress reduced dry and fresh forage yield (44% and 27% respectively).