Effective weed management practices to control complex weed flora in different cultivars of hybrid and high yielding varieties of rice (Oryza sativa L.)

A field experiment was conducted during Summer and Kharif seasons of 2007-08 and 2008-09 at Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal, India to study the effect of hand weeding and Pretilachlor 50 EC @ 500 g a.i. ha-1 as pre-emergence on weed management of different varieties of hybrid and high yielding rice. The experiment was laid out in a split-plot design with three replications for both the years. It has been observed that Pretilachlor 50 EC @ 500 g a.i. ha-1 has a significant effect to control complex weed flora both in hybrid and high yielding varieties of rice but hand weeding twice gave the better result as expected. Among the varieties, the hybrid varieties recorded 36% and 32% more grain yield in Summer and Kharif seasons respectively than high yielding varieties (HYV). The high yielding variety 6444 (V2) showed more grain yield during Summer and Kharif seasons than that of the hybrid 6129 (V1), 97158 (V6), and 96110 (V3), respectively. Regarding weed management, hand weeding twice recorded (13% & 36%) higher grain yield during Summer than that of the chemical treatment and unweeded check, and (20% & 42%) during Kharif seasons respectively. Among the interaction, hand weeding combined with all varieties of hybrid rice recorded higher yield in comparison to other treatment combinations.