Impact of High Temperature Stress on Morpho Physiological Traits and Yield of Rice (Oryza sativa L.) Genotypes

Abstract

High temperature stress is a major environmental factor that affects crop growth, development and yield, it especially limits rice yield. Hence, an experiment was conducted to study the impact of high temperature on morpho-physiological parameters and yield of rice genotypes. Ten rice genotypes were used in this study viz., N22, ADT 36, ADT 37, ADT 43, ADT 45, CO 51, ASD 16, MDU 6, TPS 5 and Anna (R) 4. The study was carried out at OTC (Open Top Chamber) with the treatments of ambient, ambient +2O C and ambient +4O C. Stress was imposed from anthesis to early grain filling period. Observations on plant height, the number of tillers, leaf area, SPAD (Chlorophyll index) and chlorophyll stability index (CSI) were done after the stress imposement and grain yield was calculated after harvest. Results revealed that, the significant changes were observed in morpho-physiological traits and grain yield of rice genotypes among the treatments and with the genotypes. N22 (10% and 19%) and Anna (R) 4 (12% and 22%) recorded less reduction of grain yield in ambient +2O C and ambient +4O C compared with ambient, due to less reduction of total chlorophyll content, SPAD values, leaf area and increased plant height. These parameters resulted in higher biomass which indirectly contributed to higher grain yield in N22 and Anna (R) 4 under high temperature