Dissecting the tolerance to combined drought and high temperature stress in foxtail millet (Setaria italica ) using gas exchange response and plant water status

Foxtail millet is an early maturing crop and has high water use efficiency, suitable for arid and semi-arid regions. Climate models predicted that the average rise in global temperature will be 1.5 ? in the next two decades. There will be an altered rainfall pattern along with a high occurrence of heat waves in foxtail millet growing regions. Therefore, understanding the response of foxtail millet to combined drought and high-temperature stress is the need of the hour. Twenty-four foxtail millet genotypes were sourced from the Indian Institute of Millet Research (IIMR), Hyderabad and Centre of Excellence, Athiyandhal. The experiment was carried out in rain-out shelter in the Department of Crop Physiology, Tamil Nadu Agricultural University (TNAU) by adapting an augmented design. All the checks alone had two replications. The plants were subjected to combined drought and high-temperature stress from peak vegetative to mid grain filling stage. Physiological and yield traits were evaluated under combined drought and high-temperature stress. The results revealed that Athiyandhal genotype ISe- 15 had better tolerance to combined drought and high-temperature stress than the other genotypes taken for the study. This genotype performed well for physiological traits such as chlorophyll index (45.76), relative water content (RWC) (69.51%) stomatal conductance (0.35 mol m-2s-1), and transpiration rate (3.19 mmol m-2s-1). Better physiological performance resulted in higher 1000 seed weight and grain yield in the tolerant genotype ISe- 15.