Elucidation of photosynthesis and yield performance of rice (Oryza sativa L.) under drought stress conditions

Abiotic stresses, particularly, drought is among the most limiting driver of crop production worldwide. This experiment evaluates the effects of drought stress on growth and yield performances as well as physiological activities of rice varieties. Nine rice accessions (GARU, NER, BIM, TOG5555, DRO1, TOG8000, IR64, BIL, and CI9453) were subjected to drought stress. Among these varieties, DRO1 and NER are drought-tolerant, IR64 is moderately tolerant, as well as TOG5555 and TOG8000 are drought-susceptible, however, the drought tolerance rate of the remaining four Afghan rice varieties is not yet reported. The results illustrated that drought stress substantially decreased the plant height, tiller number, productive tillers, plant biomass, and grain yield. In contrast, the number of unfilled-grains significantly increased under drought compared to the control conditions. Drought stress negatively affected the photosynthetic rate and chlorophyll content, which consequently decreased the spikelet fertility rate and final yield. Drought-tolerant varieties (DRO1, NER, and BIL) showed no significant difference (p > 0.05), while other were highly affected by the drought stress. Based on these results, resilience to drought stress, better photosynthesis ability caused the higher number of filled grains per panicle and yield per plant. Thus, DRO1, NER, BIL, and GARU were suggested as good performing varieties for drought-prone areas.