Growth and Yield Performance of Hybrid and Inbred Boro Rice as Affected by Different Weed Control Methods

Effective weed management is critical for reducing yield losses in rice caused by weed infestation. Although chemical weed control presents certain environmental and management concerns, it remains the most feasible option for large-scale rice cultivation, particularly when herbicides are applied at appropriate growth stages. This study assessed the growth and yield performance of selected hybrid and inbred Boro rice varieties under different weed management practices. The experiment was laid out in a randomized complete block design with three replications, involving three rice varieties—BRRI dhan29 and BRRI dhan58 (inbred) and BRRI hybrid dhan5 (hybrid)—and six weed control treatments, namely no weeding, weed-free condition, two hand weedings, pre-emergence herbicide application, early post-emergence herbicide application, and a sequential application of pre- and early post-emergence herbicides. Nine weed species belonging to five families were recorded in the experimental field, with Echinochloa crus-galli emerging as the most dominant species (SDR = 32.85) and Oxalis corniculata as the least dominant (SDR = 1.07). The combined application of pre- and early post-emergence herbicides resulted in superior weed suppression, reduced crop–weed competition, and enhanced crop performance, producing higher grain yield (6.33 t ha⁻¹), straw yield (7.31 t ha⁻¹), and harvest index (46.39%), closely comparable to the weed-free treatment. Among the tested varieties, BRRI hybrid dhan5 consistently recorded the highest grain yield (6.79 t ha⁻¹). Given the labor-intensive and impractical nature of maintaining weed-free fields, particularly under large-scale production systems, the combined herbicide approach in conjunction with hybrid rice cultivation is recommended as an effective and economically viable strategy for improving Boro rice productivity.