| dc.description.abstract | Rice (Oryza sativa L.) is an important food crop in Indonesia and serves as the source of staple food for more than half of the world’s population. This study aimed to determine the characteristics of M2 generation lowland rice plants derived from EMS-induced mutation under normal and drought stress conditions. The research was conducted in the Greenhouse of the Faculty of Agriculture, Universitas Sumatera Utara, located at an altitude of approximately 25 meters above sea level, from November 2024 to March 2025. The study used 10 seed groups, consisting of IR64 control, IR64 mutants 1, 2, 3, and 4, as well as Inpari32 control, Inpari32 mutants 1, 2, 3, and 4. Each seed group was subjected to two treatments: a control treatment using 100% water (flooded condition) and a drought stress treatment using 50% water. Sixty seeds were sown for each treatment. The observed variables included germination percentage, seedling height, number of seedling leaves, seedling leaf length and width, root length and number of roots, root morphological structure, plant height, number of leaves, number of tillers, leaf color, and chlorophyll content. The results showed that drought stress during the seedling stage inhibited germination of seeds in IR64 control and IR64 mutant 3, while other mutant seeds began germinating three days after sowing. Rice seedlings under drought stress were shorter, had fewer leaves, and smaller leaf sizes compared to the control in all seed groups (both mutant and control). However, they developed longer and more numerous roots. Drought stress induced an increase in root length and number as an adaptive response. The IR64 mutants exhibited variation in growth performance under drought stress, with two mutant groups (IR64 mutant 2 and IR64 mutant 4) showing better growth than the IR64 control, indicating higher tolerance to drought stress. | en_US |
