Evaluation of new herbicide molecules for transplanted rice

Abstract

Field experiment was conducted at Paddy Breeding Station, Tamil Nadu Agricultural University, Coimbatore during Kharif, 2012 under All India Co-ordinated Rice Improvement Programme with an objective of evaluating new molecules of herbicides for chemical weed control in transplanted rice. The experiment was conducted in randomized block design with three replications with the variety CO 47. The treatments included werebutachlor at 1.5 kg ai./ha applied at 5-7 DAT, flucetosulfuron 20 g a.i./ha at 2-3 DAT, flucetosulfuron 25 g a.i./ha at 2-3 DAT, penoxsulam + cyhalofop-butyl at 120 g a.i./ha applied at 15-20 DAT, penoxsulam + cyhalofop-butyl at 135 g a.i./ha applied at 15-20 DAT, bispyribacsodium at 35 g a.i./ha applied at 15-20 DAT, two hand weedings at 20 & 40 DAT and unweeded control. The results revealed that among the weed management practices, the lowest weed dry weight (10.47 g/m2) was recorded with application of penoxsulam + cyhalofop-butyl at 135 g a.i./ha applied at 15-20 DAT which resulted in higher grain yield of 7642 kg ha-1 and was comparable with application of bispyribac sodium at 35 g a.i./ha applied at 15-20 DAT (7487 kg ha-1). No phytotoxicity symptoms on rice was evinced on application of penoxsulam + cyhalofop-butyl at 120 and 135 g a.i./ha.