Investigation of Water Deficit Stress Effects on Yield and Yield Components Using Path Analysis in Some Corn Hybrids

This experiment was conducted to study the effects of water deficit stress on yield and yield components in eight corn hybrids. The experiment was laid out in split plot using randomized complete block design with three replications. Treatments consisted of two irrigation levels (in stress condition and without stress) as main plots, and eight corn hybrids (six late maturing single crosses and two three- way cross with moderate maturity) as sub-plots. Yield was significantly affected by water stress (p ≤%5). Other measured traits were also negatively affected, but not significantly. Hybrids showed significant differences for plant height, stem diameter, number of rows per ear, cob diameter, ear length, number of grain per row, total leaf number, number of leaves above the main ear and plant height up to position of ear emergence (p ≤ %5). Results of stepwise regression and path analysis revealed that in the non-stress condition, selection for increased yield could be performed by selecting genotypes with high percentage of cob, kernel length, number of grain per row, plant height and ear length. In the stress condition, cob diameter, number of grain per row and ear length could be used as components for selection of high yielding genotypes. Among indices used for screening of genotypes to drought stress, tolerance index could differentiate among tolerant and intolerant genotypes. For the selection of high yielding genotypes in water stress conditions, in addition to tolerance indices, other important agronomical characteristics should be considered. Based on results of this experiment Single Cross 704 and Three Way Cross 600 were recommended for normal and water stress conditions, respectively.