Productivity of Wheat (Triticum aestivum L.) as affected by low dose herbicides for management of canary grass (Phalaris minor) Seeds

A field experiment was conducted at R.M.P. (PG) College Gurkul Narsan (Haridwar) U.K. during Rabi of 2015-16 & 2016-17 to study the effect of continuous and rotational use of fenoxapop, sulfsulfuron and clodinafop on control of Phalaris Minor and Producvity of Wheat. Application of all the 3 herbicides resulted in 35-50 % increase in Wheat yield over weedy plots chesing first year of application. With continued application of these herbicides the increase in yield remained 23-27 % in sulfosulfruon-sprayed plots, 12-23 % in fenoxaprop-spryaed plots ceived rotational treatment of herbicides. Mortaility declined from 85-100 % and 10 % with fenoxaprop and 30-40 % with sulfosulfuron.

Rice-Wheat is an important cropping system in India comprising 10 mha. In India since 1970s isoproturon- a phenylurea herbicide and an intibitor of PS II in photosynthesis provided effective control of grassy weeds especially Phalaris Minor in Wheat maintaining yields. Its continuous use has resulted in the evolution of resistance in Phalaris Minor to this herbicded in Haryana and Punjab (Malik and Singh, 1995; Yaduraju et. al. 1995; Walia et.al., 1997). The resistance affected area range between 0.8 and 1.0 mha in north western India which is on the increase. Since weed populations resistant to one category of herbicids are know to be managed by herbicides with alternate mode of action, three alternate herbicides, viz. fenoxaprop-p-ethyl, clodinafop-propargyl and sulfosulfuron were recommended for management of herbicide- resistant populations of Phalaris Minor in 1997-98. While fenoxaprop and clodinafop are inhibitors of acetyl co onzyme-a- carboxylase (AC case), the first enzyme in fatty acid synthesis path, sulfosufuron is an inhibitor of acetolaclate the first enzyme.