Assessing antioxidant system and yield of maize (Zea mays L.) inbreds under elevated temperature condition

Maize (Zea mays L.) is the most important food and feed crop grown under diverse soil and climatic conditions. Among the cereals, demand for maize is increasing year after year, but fluctuation in climatic conditions especially the temperature extremes is the current and future threat in maize cultivation. Each degree Celsius increase in global mean temperature causes yield reduction up to 7.4 per cent in maize. The high temperature stress impact at the reproductive stage affects grain filling rate and duration. Adaptation of maize crop to future warmer climatic conditions requires a better understanding of physiological responses to elevated temperatures. With this view, a pot culture experiment was conducted at the Department of Crop Physiology, TNAU, Coimbatore during the summer season of 2020. Two maize inbreds viz., UMI 1230 and CBM-DL- 322 were taken for the study and exposed to high temperature stress treatments viz., T1 - ambient, T2 - ambient+4°C and T3 - ambient+6°C (44°C) for 10 days during the reproductive stage to assess the changes in biochemical and yield traits. The ambient+4ºC treatment revealed that the maize inbred line CBM-DL-322 recorded lower malondialdehyde content with over production of antioxidant enzyme activity (superoxide dismutase, catalase and ascorbate peroxidase). Cob weight and seed set parentage showed a negative correlation with both elevated temperatures. It is concluded that the maize inbreds line CBM-DL- 322 performed better at an elevated temperature at ambient+4°C and recorded more cob weight (57.09g) compared to UMI 1230 inbred (43.56g).