A reliable and rapid assessment technique, for evaluation of cultivars having potential to combat harsh environmental conditions is imperative. This experiment was carried out to screen 8 local (Sindh Pakistan) accessions of rice at early growth stage at control (28±3°C) and heat shock (42±3°C) for different time periods (24, 48, 72 hrs). Heat stress indices, including promptness index (PI), germination stress index (GSI), plant height stress index (PHSI), shoot length stress index(SLSI), root length stress index(RLSI) and dry matter stress index (DMSI) were used to explore thermotolerance. It is observed that heat stress affected germination potential and reduced dry matter but cultivars showed variation. Among all, cultivars “Kanwal-95” and “Sada Hayat” showed more thermotolerance in terms of maximum number of germination as well as in speediness to germination along with good seedling establishment. While “Shahkar” and “DR-82” showed susceptibility with low germination percentage and bad seedling establishment. A positive correlation was also observed between germination potential and seedling establishment. Results analysis revealed that these indices were simple and accurate selection criteria and can be adopted to save resources and time of formers.
