Evaluation of Advanced Sorghum Lines for Heat Tolerance Under Agro-Ecological Conditions of Dera Ismail Khan, Pakistan

Background and Objective: Sorghum is a vital cereal crop for Pakistan, particularly in arid and semi-arid regions where heat stress is a major challenge for crop production. This study aimed to assess the performance of different sorghum lines under heat stress conditions at the Arid Zone Research Centre, Dera Ismail Khan, Khyber Pakhtunkhwa, Pakistan. Materials and Methods: The experiment was conducted using a Randomized Complete Block Design (RCBD) having three replications. Ten sorghum lines/varieties were evaluated under heat stress, with key agronomic traits recorded, including plant height, days to 50% heading, leaf area index, leaves/plant, stem girth, maturity days, crop growth rate, grain count per head, head weight, 1000-grain weight, plant biomass, grain yield, and harvest index. Temperature fluctuations and heat stress indices were monitored throughout the study. Data were analyzed using Statistix 8.1 Software through ANOVA, and treatment means were compared using the LSD test at a 0.05 significance level. Results: Significant variation was observed among the sorghum lines. The sorghum line SS 97-2(S1), followed by the variety Dera Jowar, exhibited the highest agronomic and yield-related attributes, making them the most suitable for cultivation under heat-stressed agro-climatic conditions of the arid zone. Conclusion: The study provides valuable insights into the selection of heat-tolerant sorghum varieties, which can enhance productivity in arid and semi-arid regions. While the results indicate promising candidates for heat-stressed environments, further multi-location trials and molecular studies are recommended to validate findings and explore underlying genetic mechanisms for heat tolerance.