Evaluation of the efficacy of bispyribac-sodium on transplanted rice (Oryza sativa L.) in northern hill region of Chhattisgarh

A field experiment was conducted at the Instructional-cum-Research Farm, Raj Mohini Devi College of Agriculture and Research Station, Ambikapur, Chhattisgarh during the kharif season of 2024 to assess the “Evaluation of the efficacy of Bispyribac-sodium on transplanted rice (Oryza sativa L.) in the northern hill region of Chhattisgarh.” The trial consisted of six treatments, namely: T₁- Unweeded check, T₂- Two hand weeding at 20 and 40 DAT, T₃-Bispyribac-sodium 10% SC @ 20 g a.i. ha^-1 at 20 DAT, T₄- Bispyribac-sodium 10% SC @ 40 g a.i. ha^-1 at 20 DAT, T₅- Bispyribac-sodium 10% SC @ 60 g a.i. ha^-1 at 20 DAT and T₆-Bispyribac-sodium 10% SC @ 80 g a.i. ha^-1 at 20 DAT, arranged in a Randomized Complete Block Design (RcBD) with four replications. In the experimental field, lowest weed density and dry weight along with the highest weed control efficiency were observed under Two hand weeding at 20 and 40 DAT (T₂), which was statistically comparable to Bispyribac-sodium @ 80 g a.i. ha^-1 (T₆) and Bispyribac-sodium @ 60 g a.i. ha^-1 (T₅). Weed infestation in the Unweeded check (T₁) reduced the grain yield of rice by 41.51%. These results further indicated that the growth and yield attributes of transplanted rice such as plant height, number tillers hill^-1, number leaves hill^-1, plant dry matter accumulation, number of panicles hill^-1, number of grains panicle^-1, test weight, grain yield, straw yield and harvest index were maximum in Two hand weeding at 20 and 40 DAT (T₂). This treatment was statistically at par with Bispyribac-sodium @ 60 g a.i. ha^-1 (T₅) and Bispyribac-sodium @ 40 g a.i. ha^-1 (T₄), which also resulted in significantly higher rice yields without any phytotoxicity, except at the Bispyribac-sodium 80 g a.i. ha^-1 dose, where adverse effects were noticed.