The research project was carried out at the Maize and Millets Research Institute in Yusafwala-Sahiwal during the crop season of 2022) using a split-plot design. The present investigation explored the effects of individual and combined effects of water stress and heat stresses on morpho-phenological, physiological and biochemical traits in eight local (YH-5482, YH-5427, YH-5407, FH-1046, YH-5399, JPL-1908, SB-9663 and YH-1898) and two exotic maize hybrids (NK-8441 and P-1543). Significant variations were observed among maize hybrids under discrete and shared effects of water stress and heat stresses for key morphometric and other agronomically important, grain-related traits. Correlation analysis exposed strong positive correlation of grain yield with SPAD value (r= 0.88**), Proline (r= 0.79**), transpiration rate (r= 0.78**), superoxide dismutase (r= 0.73**), stomatal conductance (r= 0.72**) while negatively correlated with hydrogen peroxide (r= -0.87**). Cluster analysis grouped local and exotic maize hybrids into three groups under stress conditions and exposed that local maize genotypes/hybrids, predominantly YH-5427, YH-5482 and YH-5395 were the maximum stress tolerance under individual as well as combined heat + water-stress conditions.
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