ASSESSMENT OF PHYSIO-BIOCHEMICAL INDICATORS FOR DROUGHT TOLERANCE IN DIFFERENT CULTIVARS OF MAIZE (ZEA MAYS L.)

Maize is an important cereal crop all-over the world and has been recently ranked at first among all cereal crops. However, growth of maize plants is negatively affected in arid and semi-arid areas of the globe due to scarcity of water, but genetically variable cultivars/lines differ considerably to respond to water limited conditions. To evaluate the response of some commercial cultivars of maize to water deficit conditions, a pot experiment was carried out. Eight maize cultivars (Sultan, Akbar, Pearl, MMRI, Maki Pak, Sahiwal 2002, Sadaf and Neelum) were subjected to varying [100%, 75% and 60% of field capacity (FC)] levels of water deficit conditions. Drought stress significantly decreased shoot fresh and dry weights, root fresh and dry weights and chlorophyll pigments (a and b) in all maize cultivars. However, free proline, glycinebetaine (GB), total phenolics, hydrogen peroxide (H2O2), malondialdehyde (MDA) contents, activities of enzymatic antioxidants (CAT, POD and SOD) and ascorbic acid (AsA) contents increased significantly under water deficit conditions. Of all maize cultivars, cv. Sadaf was superior in terms of plant growth, while, cv. Sultan proved to be inferior to the other cultivars examined in this study. It was concluded that osmoprotectants such as proline and GB can be used as stress tolerance indicators under drought stress conditions.