Evaluation of heat tolerance in cowpea genotypes for sustained productivity under high temperatures

Aim: The study aimed to evaluate heat tolerance in cowpea genotypes under high-temperature and identify thermotolerant genotypes that can sustain productivity in environments with temperatures exceeding 35°C. Methodology: A total of 191 cowpea genotypes were screened for yield attributes at two locations, Bangalore and Raichur, which differed in temperature exposure. Heat stress effects on different physiological traits were measured and contrasting genotypes were further assessed using the temperature induction response (TIR) approach. Results: Significant reductions in total dry matter and yield traits were observed at high-temperature location, Raichur. However, heat-tolerant genotypes exhibited minimal reduction in total dry matter and root length. Ten genotypes, including IC-402172, EC-458453 and NBC-21, demonstrated consistent thermotolerance at both field and cellular levels. Interpretation: The study identified specific cowpea genotypes that can tolerate high temperatures up to 35°C without significant loss in productivity, providing valuable candidates for crop improvement. Key words: Cow pea, Heat stress, Temperature induction response, Thermotolerance