SRAVANTHI G., DHEERAVATHU S. N., LATHA P., AVINASH S., JACOB J., VIJAYA KUMAR G. AND C. ARUNA REDDY
Indian Institute of Millets Research, Hyderabad- 500030, (Telangana), India
Department of Crop Physiology, SVAC, Tirupati, (Andhra Pradesh), India
Department of Crop Physiology, Agricultural College, Bapatla (ANGRAU) (Andhra Pradesh), India
*(e-mail: sevanayak2005@gmail.com)
(Received: 6 November 2025; Accepted: 17 December 2025)
SUMMARY
Global climate change, characterized by rising temperatures and fluctuating rainfall, poses a major threat to sorghum productivity. The present study evaluated the physiological responses of two sorghum lines (AKR150 and C43) under field conditions during the 2024 and 2025 summer seasons at ICAR–IIMR, Hyderabad. Weather data indicated higher temperatures, reduced relative humidity, and increased sunshine hours in 2025, creating intensified heat stress conditions. Physiological traits-chlorophyll content (SCMR), canopy temperature depression (CTD) and membrane stability index (MSI) were significantly affected by the climatic variation. Both genotypes exhibited declines in chlorophyll content and MSI under 2025 heat stress; however, AKR150 maintained higher chlorophyll stability and greater CTD, indicating efficient canopy cooling and superior thermotolerance. Conversely, C43 showed higher MSI but experienced sharper chlorophyll loss, reflecting moderate tolerance. This study highlights the effects of climatic variability on sorghum physiology and identifies AKR150 as a promising genotype for breeding programs targeting the development of heat-resilient cultivars suited to future climate conditions.
Key words: Canopy temperature depression, climate change, Sorghum, SPAD chlorophyll meter reading