Global warming poses a severe threat to agricultural ecosystems worldwide. Rice is staple food for almost half of world population. Heat stress is harmful for rice crop at reproductive stage. Under such scenario, for maintaining rice productivity and further enhancing it, it is necessary to study the morpho-physiological aspects of the heat stress tolerance in rice at reproductive stage. 22 rice genotypes were phenotyped on the basis morpho-physiological traits in field for heat stress tolerance. Exposure to heat stress at reproductive stage resulted in reduction in the number of productive tillers, number of filled grains and unfilled grains, panicle length, MSI, total dry matter and harvest index and increase in number of unfilled grains. However, some of the genotypes such as Rasi, RNR15048, KNM 1638 has performed on par with the control under heat stress. Hence, these genotypes can be considered as heat stress tolerant genotypes.

Heat Stress, Rice, Abiotic stress, Physiology, Reproductive stage

Heat stress in rice genotypes negatively impact the MSI, number of productive tillers, number of filled grains, panicle length, total dry matter and HI but positively increased the number of unfilled grains. Based on six traits as mentioned above, the genotypes Rasi, RNR15048, KNM1638, Gaja-Baru and Bakal performed at par with their control counterparts under heat stress. N22 a heat tolerant check also performed on par with its control. Therefore, these genotypes can be considered as heat stress tolerant genotypes. In response to heat, the genotypes Moshi, Maha-Chai and BPT5204 have shown reduction in the above mentioned parameters, which is similar to Vandana, a heat sensitive donor and therefore these genotypes can be considered susceptible to heat stress. Thus, it can be concluded from this study that heat stress causes a negative influence during the reproductive stage, morpho-physiological traits can be used to screen genotypes for heat stress tolerance studies. Further research is needed to confirm the findings of this experiment.

V. Nandhini, Akshay S. Sakhare, Ch. Aruna Kumari, D. Sanjeeva Rao and J. Aravind Kumar (2023). Field Phenotyping of Rice Genotypes for Heat Stress Tolerance based on Morpho-physiological Parameters at Reproductive Stage. Biological Forum – An International Journal, 15(11): 390-397.