The Terminal Heat Stress and its Effect on Yield and Yield Contributing Traits of Wheat (Triticum aestivum L.) Genotypes

An experiment was conducted with wheat genotypes NWL-14, K-9162, NWL-1014, NWL-12-2, NWL-12-4, NWL-10-4, K-910-30, NWL-4035, DBW-16, DBW-187, NWL-12 (3) T, Halna, HD-2967 to evaluate heat tolerant in wheat at instructional farm and in the laboratory of Crop Physiology & Plant Molecular Biology and Genetic Engineering, Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya, India, during rabi season of 2021-2022. Heat stress was induced by delayed sowing 45 days from normal date of sowing (02 December 2022)-(17 January 2023) so that delay sown wheat genotypes could experience heat stress at reproductive stage. Heat tolerant wheat genotypes screened on the basis of Relative Water Content, Catalase activity, plant height, tiller number, number of grains per spike, test weight and grain yield per plant over control under heat stress condition. Heat stress reduces the the growth and yield irrespective of wheat genotypes but heat tolerant genotypes Halna, NWL-1293)T, NWL 10-2 and NWL-12-4 showed less reduction over susceptible ones. Relative water content, proline and catalase activity can be used as a physiological screening indices for heat tolerant genotypes.