Bio-efficacy of various herbicides and their mixtures on weeds and yield of wheat (Triticum aestivum) under subtropical agro-ecosystem

A field experiment was conducted during the winter (rabi) season of 2004-05 and 2005-06 to study the effect of various herbicides and their mixtures on weed growth, yield attribute and yield of wheat (Triticum aestivum L. emend. Fiori & Paol.) under irrigated conditions of subtropical agro-ecosystem of Jammu region. The weed flora observed at site were Anagallis arvensis, Poa annua, Phalaris minor, Trachyspermum and Euphorbia helioscopia, of which the relative density of individual weed species out of total weeds corresponds to 1.1 1 to 4.69 per cent on application of fenoxaprop+metribuzin (120+100 g ailha) at 60 days after sowing (DAS). Among the weed-control treatments, fenoxaprop+metribuzin (120+100 g ailha), though on a par with either tank mix ap- plication of sulfosulfuron + 2,4-D (25+500 g ailha), clodinafop + metsulfuron (60+2 g ailha), isoproturon+2,4-D (750+500 g ailha) or alone application of sulfosulfuron (25 g ailha), metribuzin (175 or 200 g ailha) and isoproturon (1,000 g ailha), reduced the dry weight of weeds significantly than weedy check and other herbicide treatments. It led to significant increase in the yield attributes, viz. effective tillerslm, grainslear and 1,000-grain weight, and the yield of wheat than the rest of the treatments, during both the years of experimentation. Maximum grain yield and yield attributes were recorded in weed-free plots, and reduction of 42.29 and 38.27 per cent in yield was observed in weedy check plots during 2004-05 and 2005-06 respectively.