Evaluating the Performance of bread Wheat (Triticum aestivum L.) Genotypes for terminal Heat tolerance

Terminal heat stress is a key yield-reducing factor in late sown wheat. Twenty-five bread wheat genotypes were evaluated for terminal heat tolerance by planting in normal (non-stress) and late (stress) environments. To check the tolerance level of genotypes to heat stress, indices namely mean performance of genotypes, heat susceptibility index, and heat susceptibility percent were studied. The analysis of variance revealed significant variation due to genotypes for all characters in two sowing dates except grain filling period. In heat stressed environment, genotypes DBW 107, HUW 688, UP 2883, K 1314, HD 3118, HI 1604 and HD 3159 had high per se performance for grain yield/m². Genotypes HD 3164, GW 463, PBW 718 and CG 1015 showed low heat susceptibility index (HSI<1) for grain yield/m² and were thus consider as heat tolerant genotypes. Reduction in grain yield/m² (14.97%) was mainly associated with a reduction in grain filling period (16.73%).