Due to intensive cropping system, late planting of wheat is very common which causes plants to suffer due to terminal heat stress. To adapt and mitigate the adverse effect of heat on wheat, researchers want to develop heat-tolerant wheat genotypes. Therefore, a set of 11 germplasms of wheat was sown in normal period (November 25) as well as in late period (December 25) at Instructional Farm of Swami Keshwanand Rajasthan Agricultural University, Bikaner. Various physiological, gas exchange and yield attributes were measured at different crop growth stages. Results showed that days to anthesis (DTA), relative water content (RWC), membrane stability index (MSI), photosynthetic pigments, photosynthetic rate (A), stomatal conductance (gs), internal CO₂ concentration (ci), water use efficiency (WUE) and yield attributes were reduced, whereas transpiration rate (E) was increased under late sown as compared to normal. Most of the physiological and yield characters showed superiority (highest/lowest) in germplasm entry no. 26 followed by 43 and 58. Heat susceptibility index (HSI) was the lowest, whereas chlorophyll stability (CSI) and heat tolerance index (HTI) were the highest recorded in entry 26 followed by 43. Heat-tolerant germplasm could be selected on the basis of high RWC, MSI, photosynthetic pigments, CSI, A, gs, ci, WUE, yield components and HTI, and low E and HSI. In the present investigation, entry no. 26 (IC279317), 43 (IC335971) and 58 (IC336816) were found the best suited germplasm under heat stress. These germplasms supposed to carry the heat-tolerant genes and may be used for further heat tolerance breeding.

由于集约化种植系统，小麦的后期播种非常普遍，这会导致植物因终末热胁迫而遭受损失。为了适应和减轻热量对小麦的不利影响，研究人员希望开发耐热小麦基因型。因此，在正常时期（11月25日）和后期（12月25日）在比卡内尔的Swami Keshwan和Rajasthan农业大学的教学农场播种了11种小麦。在不同的作物生长阶段测量了各种生理，气体交换和产量属性。结果表明，开花期（DTA），相对水含量（RWC），膜稳定性指数（MSI），光合色素，光合速率（A），气孔导度（gs），内部CO ₂与正常相比，后期播种时的浓度（ci），水分利用效率（WUE）和产量属性降低，而蒸腾速率（E）提高。多数生理和产量性状在种质入库号No.1中显示出优势（最高/最低）。26位紧随其后，依次为43和58。在条目26中记录的热敏指数（HSI）最低，而叶绿素稳定性（CSI）和耐热指数（HTI）最高，其次是43。高RWC，MSI，光合色素，CSI，A，gs，ci，WUE，产量成分和HTI以及低E的基础和恒指。在本调查中，条目号 发现26（IC279317），43（IC335971）和58（IC336816）在热胁迫下最合适。这些种质应该携带耐热基因，可以用于进一步的耐热育种。