Boro rice, Cultivars, Herbicides, Unweeded control, Weed free

A field experiment was conducted to test the efficacy of different herbicides and cultivars during boro seasons of 2009 and 2010 on clay loam soils at BHU, Varanasi. The herbicides used were butachlor 1500 g/ha (pre-emergence) fb 2,4–D 500 g/ha + NIS (0.25%) at 20-25 DAT, pretilachlor 750 g/ha (pre-emergence) fb azimsulfuron 35 g/ha + NIS (0.2%) at 15 DAT, penoxsulam 22.5 g/ha + NIS (0.25%) at 15 DAT, ethoxysulfuron 18 g/ha + fenoxaprop + safner 56 g/ha + (NIS 0.25%) at 15 DAT, propanil 3000 g/ha + trichlorpyr 500 g/ha + NIS (0.25%) at 20-25 DAT and pyrazosulfuron 20 g/ha (pre-emergence) fb bispyribac 25 g/ha + NIS (0.25%) at 25 DAT under ‘Gautam’, ‘Prabhat’ and ‘Krishna Hamsa’ cultivars. Weed count and its dry matter under ‘Prabhat’ cultivar were lower than that with other two cultivars for both Echinochola and Cyperus spp. resulting in higher weed control efficiency with Prabhat as compared to other two cultivars whereas, significantly highest grain yield of 4.15 t/ha was obtained in Gautam cultivar due to higher growth and yield attributes. The application of ethoxysulfuron + fenoxaprop was most effective in minimizing population of Cyperus spp. and its dry matter with highest WCE. ‘Gautam’ cultivar with highest net return of Rs. 24,898/ha and benefit cost ratio of 1.19 and pretilachlor fb azimsulfuron with net return of Rs. 27,461/ha  and benefit: cost ratio of 1.32 were found most profitable among the cultivars and herbicidal treatments, respectively.