Effect of Optimized Paclobutrazol Dosage on Plant Height and Yield of the INPARI 33 Rice Variety

Abstract This study investigated the effects of paclobutrazol (PBZ) on plant height and yield potential of the INPARI 33 rice variety. Previous research on the local rice variety Genjah Arum demonstrated that a PBZ concentration of 250 mg L⁻¹ was optimal for reducing plant height without compromising yield. Building upon these findings, this study applied PBZ at 250 mg L⁻¹ to regulate excessive vegetative growth and evaluate its impact on INPARI 33. The results indicated a significant reduction in plant height and internode length in PBZ-treated plants compared with the control. Despite a minor reduction in panicle length, PBZ-treated plants exhibited an improved seed-setting rate and an increased yield potential of 0.77 tons per hectare. These findings suggest that PBZ application at 250 mg L⁻¹ is effective in modifying plant architecture while maintaining or increasing yield, thereby presenting a valuable strategy for optimizing rice production in high-input agricultural systems. Future studies should focus on refining PBZ application rates and timing to maximize its benefits across diverse growing environments.