Wheat (Triticum aestivum L.) production has had increasing challenges with rising temperatures due to climate change. This study aimed to evaluate the genetic potential of bread wheat F₃ populations and their parents under terminal heat stress using physio-morphic traits via a randomized complete block design. Five F₃ populations, derived from diverse crosses, entailed assessment in climatic conditions of Sargodha, Pakistan. Significant variation among populations emerged for all traits. The cross Punjab 76 × E109 outperformed in grain yield per plant (17.20 g), the number of tillers per plant (8.59), the number of seeds per spike (75.83), and cell membrane thermostability (CMS, 95.65%). Akbar 2019 × E145 and E116 × C228 also exhibited high-yield potentials. High heritability (0.99), genetic advance (9.12), and strong positive correlations appeared for grain yield with spike length, tiller number, and CMS. Principal component analysis (PCA) revealed that PC1 and PC2 explained 84.61% of the total variation, confirming trait clustering. Among parental lines, C271 (98.19 cm) and E121 (11.90 g) showed a good performance for plant height and yield, respectively. These results suggest that crosses like Punjab 76 × E109 and Akbar 2019 × E145 can serve as potential genetic sources for improving heat resilience and productivity in wheat.

Keywords: wheat (T. aestivum L.), F₃ populations, PCA, climate resilient, CMS, biplot, yield-related traits, grain yield

Key findings: Heat stress affects a lot of grain yield production of wheat (T. aestivum L.). A reduction of 3%–10% of grain yield occurred in wheat caused by an increase of each one °C ambient temperature. Out of five populations, three F₃ populations, such as Punjab 76 × E109 (17.20 g), Akbar 2019 × E145 (12.07 g), and E116 × C228 (11.53 g), yielded better for grain yield per plant than the parents under terminal heat environment. Therefore, these populations are candidate-breeding lines for developing heat-resilient wheat cultivars.