Assessment of qualitative and quantitative traits of grain corn hybrid KSC704 under drought stress and different levels of nitrogen fertilizer

To assess the quantitative and quantitative traits of KSC704 corn hybrid under drought stress and nitrogen fertilizer levels, an experiment was carried out in research farm of Islamic Azad University in Varamin in 2009, using a split-plot based on randomized complete block design with four replications. The main plot consisted of four levels of drought stress (0, 100, 150, and 200mm evaporation from evaporation basin A pan) and subplot was three levels of nitrogen fertilizer (80, 130, 180kg, pure nitrogen per hectare). Assessment of different traits showed significant differences among them in different treatments of drought stress and nitrogen levels. These treatments affected grain yield either through total number of grains per ear or 1000 grain weight. The highest grain yield 8919 and 7078kg ha-1. were obtained in treatments of 50mm evaporation and 180 kg nitrogen, respectively. Studying the growth trend, it was clear that the effect of drought stress on stem dry weight at the end of season was more than that on dry leaf weight. Drought stress in the second half of growth season decreased stem dry weight significantly but had no effect on leaf dry weight, indicaling that drought stress increased dry matter remobilization from stem to grains. In addition, total dry weight was decreased significantly with increasing water stress. Changes in relative water contents as influence by irrigating regime, and nitrogen fertilizer, demonstrated the effects of experimental factors on resource strength. Accumulative increase of nitrogen led to reduction of drought strength. Accumulative increase of nitrogen led to reduction of drougth stress effects due to increase of relative water contents and consequently decreasing of catalase enzyme’s activity.