Journal of Plant Process and Function

In order to investigate the response different of maize hybrids under drought stress in different levels growth stages, a field experiment was done as split plot layout based on randomized complete block design with three replications, in crop school of Meghan of Agriculture and natural Resources in year 2014. The treatments were included three irrigation regimes (Full irrigation, deficit irrigation at flowering and grain filling stage irrigation) in the main plots and seven commercial hybrids (single cross such as 260, 301, 302, 400, 500, 704 and 370 double-cross) the subplots assigned. Analysis of variance showed that the effect of drought stress levels, hybrids and interaction of drought stress level and hybrids were significant on protein content, carbohydrates, lysine, methionine, proline and activity of catalase, peroxidase and polyphenol oxidase. Grain yield was significantly influenced only by the main effect of stress and hybrids. The stress enhanced in most hybrids in protein, proline, carbohydrate and activity of catalase, peroxidase and polyphenol oxidase contents and reduction in the amount lysine and methionine contents. The highest enzyme activity and grain yield were observed in drought stress conditions of single cross 704 and the highest compatibility of metabolites were in stress of single cross hybrid 400 and 500. The highest grain yield of hybrid single cross 704 with an average 11.49 t/ha was obtained. The regression results also showed that in non-stress condition carbohydrates, highest contribution in predicting the yield and in stress conditions amount lysine and proline highest share of in determining yield to own devoted.