Abstract
The current experimental study was conducted in tunnel conditions at Maize and Millets Research Institute (MMRI), Yusafwala, Sahiwal to characterize one hundred (100) maize inbred lines for their heat tolerance ability on the basis of morpho-phonological traits. Data was recorded for different heat stress related primary and secondary plant traits i.e. days to 50% tasseling, days to 50% silking, anthesis-silking interval, plant height, ear height, ear length, 1000-grain weight and grain yield per hectare. The results revealed high genetic divergence among maize inbred lines for their high temperature stress tolerance capacity. Correlation analysis unveiled the significantly positive association of plant height with grain yield (0.683**) and thousand grain weight (0.974**) while strong negative association with ear height (-0.831**) and ear length (0.631 **) under heat stress conditions. Cluster analysis classified maize inbred lines into four clusters in which cluster consisted of highly productive inbred lines under heat stress. Similarly, Principal component analysis categories maize inbred lines for their heat stress tolerance and susceptibility. Based on these results, best parent lines will be selected for the improvement/development of climate resilient maize genotypes.
