Autotoxic Effects of Rice Bran on Seed Germination, Growth and Yield Component in Rice (Oryza sativa L.)

Abstract

The development of natural weed control methods using agricultural waste is gaining attention as part of sustainable farming practices. Rice bran is one such potential material; however, its application may adversely affect rice plants themselves. The aim of the research were to determine the concentration of rice bran water extract that inhibits rice germination and growth,  determine the Inhibition Concentration (IC50) (50% inhibition concentration) of rice bran water extract in suppressing seedling growth and to evaluate the effect of rice bran extract concentration on rice growth and its impact on yield components.The research was carried out at the Agronomy Laboratory and Greenhouse, Department of Crop Production, Faculty of Agriculture, University of Bengkulu, Indonesia from November 2024 to March 2025. A completely randomized design (CRD) was employed, in a single factor with five extract concentration treatments (0%, 2.5%, 5%, 7.5%, and 10%) and five replications. Observed variables included germination indicators such as radicle and plumule length, dry weight of radicle and plumule, and percentage of abnormal seedling, as well as growth and yield variables, including plant height, number of leaves, number of tillers, leaf area, panicle length, number of panicles per hill, leaf greenness, flowering time, 1,000 grain weight, and dry weight of roots and shoots. The research showed that within the concentration range of 0-10%, higher rice bran extract concentrations significantly suppressed rice germination, as indicated by increased abnormal seedlings, reduced shoot-root length, and lower seedling weight compared to lower concentrations. At 4.72% rice bran extract concentration effectively inhibited rice test plant germination, with 50% of seedlings showing abnormalities, stunted radicles and plumules, and black spots on the grains. At 10% concentration, both vegetative growth and yield components of rice were more severely suppressed compared to lower extract concentrations.These results suggest that rice bran possesses autotoxic potential that could be harnessed as an eco friendly bioherbicide. However, proper management of rice residues in the field is essential to prevent negative impacts on crop productivity.