Weed competitive ability and productivity of transplanted rice cultivars as influenced by weed management practices

Weed competitive ability of six rice cultivars including three hybrids [Arize 6129 (short duration); Arize 6444 (medium duration), Arize Dhani (long duration)] and three varieties [Swarna Shreya (short duration); Rajendra Sweta (medium duration); MTU 7029 (long duration)] was evaluated under three weed pressures i.e. low weed pressure [pre-emergence application (PE) of pretilachlor 0.60 kg/ha at 2 days after transplanting (DAT) followed by (fb) post-emergence application (PoE) of bispyribac-sodium 30 g/ha at 20 DAT fb 1 hand weeding (HW) at 35 DAT; medium weed pressure (pretilachlor PE at 2 DAT fb bispyribac-sodium PoE at 20 DAT) and high weed pressure (weedy check)]. Experiment was conducted during rainy seasons of 2018 and 2019 at the ICAR-Research Complex for Eastern Region Patna, Bihar. The major weeds recorded with transplanted rice were Brachariaria ramosa, Trianthema portulacastrum, Cyperus rotundus, Echinochloa colona, Caesulia axillaris and Physalis minima. Rice hybrids, viz. Arize 6444 and Arize Dhani, and rice variety Swarna Shreya recorded significantly lower weed biomass compared to other varieties. Weeds reduced rice grain yield by 31.37%. Long-duration and short statured rice variety MTU 7029 was more susceptible to weed competition compared to other varieties and hybrids. Early duration hybrid Arize 6129 recorded low weed pressure, maximum rice grain yield (6.57 t/ha) and economic returns.