Effect of Gas Exchange, Antioxidative Enzyme Activities and Yield Characteristics of Maize Inbred Lines under Drought Stress

Globally, drought is one of the major environmental factors responsible for reducing crop productivity. Maize (Zea mays L.) is a C₄ monocotyledonous plant cultivated widely for its high-yielding grains. Moreover, it serves as a staple food and feedstock in various industries because of its genetic diversity and adaptability. Water deficit negatively impacts various physiological and biochemical traits of maize, resulting in yield losses of approximately 30 to 90%. Hence, a field evaluation was carried out during Kharif 2023, with maize inbreds CBM-DL 38, CBM-DL 111, CBM-DL 238, CBM-DL 448, CBM-DL 360 and UMI 1200, where they were exposed to drought. Sample collection was performed 10 days after stress was imposed. Physiological (gaseous exchange parameters), biochemical (relative water content, proline, malondialdehyde, and antioxidant enzymes) and yield parameters were recorded. The results revealed that drought stress negatively affects the gaseous exchange parameters, relative water content and yield. CBM-DL 238 and UMI 1200 presented lower values of proline and antioxidants, indicating a reduced ability to cope with drought. On the contrary, these four inbred lines, CBM-DL 38, CBM-DL 111, CBM-DL 448 and CBM-DL 360, presented increased proline and antioxidant activities because they reduced the malondialdehyde content in the leaf tissue under drought. The antioxidant enzyme activities and yields of CBM-DL 38, CBM-DL 111, CBM-DL 448 and CBM-DL 360 inbred lines increased under drought conditions. Therefore, the above four maize inbred lines perform better under water deficit conditions.