Study of yield and yield components of corn (Zea mays L.) inbred lines to drought stress
In order to study the effects of drought stress on yield and yield components of seven corn inbred lines, a field trial was conducted under non-stress and different drought stress conditions (stress at vegetative (6 to 7 leaves), pollination and grain filling stages) at the Agricultural College of Islamic Azad University, Shoushtar branch, Iran, 2010. The experiment was arranged in a split-plot design by a randomized completely block design with three replications. Drought stress in grain filling stage had the minimum grain yield, grain number per ear and grain number per row that showed severe effects of drought stress at this stage of growth. Based on the results of this study, the inbred line K166B produced the highest grain yield, grain number per ear, row number per ear, grain number per row, grain depth, grain width and grain weight. But line MO17 produced the least grain yield, grain number per ear, row number per ear, grain number per row, ear diameter and cob diameter. Therefore, lines K166B and MO17 were the most tolerant and sensitive to drought stress, respectively and could be recommended for use in future breeding programs for production of drought tolerant hybrids. Results show that grain number per ear, grain number per row and grain width traits have the positive and significant correlation with grain yield. The stepwise regression results for grain yield indicated that grain number per ear in the model was the input and 99% determined the variation of the traits grain yield by grain number per ear. Therefore, grain number per ear provided the most useful input for an increase of grain yield in a drought stress condition.
Key words: Corn, correlation, drought stress, stepwise regression, yield components