Effects of drought stress and Selenium application on yield and yield components of two maize cultivars

To evaluate the effects of water deficit stress and Selenium application on maize yield and yield components, a field study was carried out in 2008 as a split-split plot design based on randomized complete block. In this study, irrigation treatments included irrigation cutoff at full flowering stage and irrigation up to the end of growth period as main plots, studied cultivars included SC700 and SC613 as sub-plots, and Selenium treatment from sodium selenite source (spraying at full silking stage) constituted sub-sub-plot. The results showed that there were significant differences between irrigation treatments and cultivars as well as Selenium levels at probability level of 99%. Means comparison of cultivars showed 46% decrease in yield under stress condition. Selenium application increased yield under water deficit stress. It also increased thousand-grain weight and grain number/ear. Thousand-grain weight and grain number/ear were affected by water stress and Selenium application. SC700 had the highest thousand-grain weight and yield. The highest leaf area index was observed at grain filling stage both in control and drought stress treatments. Selenium application decreased leaf area index, so that SC700 had the lowest leaf area.