Banding Patterns Activity of Antioxidant Enzymes and Physiological Attributes in Maize (Zea mays L.) Families under Water Deficit Stress

In order to assess the effect of water-deficit stress on the activity of antioxidant enzymes and agro-physiological attributes of maize, a split-plot field experiment was conducted with three replications based on the randomized complete block design. Three levels of irrigation (well-watered, intermediate and severe water-deficit stress) and four maize families including 10 genotypes were considered as the main and sub factors, respectively. Post treatment, the electrophoretic analysis of three enzymes in maize leaves including SuperOxide Dismutase (SOD), Catalase (CAT) and Peroxidase (POX) was carried out on 8% horizontal acrylamide gel. Moreover, agro-physiological attributes such as MalonDiAldehyde (MDA), H2</sub>O2</sub>, chlorophyll index (SPAD), Relative Water Content (RWC), and grain yield were measured. Concomitantly with increasing intensity of water-deficit stress, the activity of most isozymes and the contents of MDA and H2</sub>O2 </sub>increased while POX2 activity, chlorophyll index, RWC, and grain yield decreased. Under intermediate stress, POX1 isozyme in Lia0688 line (233%) and, under severe stress, POX2 isozyme in AR68 hybrid (201%) showed higher increase compared with the well-watered treatment. Overall, POX1, SOD2, CAT isozymes and MDA, chlorophyll index, and RWC were identified as suitable traits. Based on enzyme activity and agro-physiological attributes, SC706 and TWC647 hybrids were superior to the other genotypes and expressed higher tolerance to water deficit stress. Moreover, among parental lines, MO17, B73 and Lia0688 were promising, although Lia0688 and MO17 were more tolerant lines and showed better performance compared with the line B73 and other lines under well-watered and stress conditions.