Wild oat-wheat interaction in Iran

Abstract

Wild oat is a weed that commonly infests cereal crops. A large number of studies have been conducted, generally finding that wild oat has negative effects on crop production, particularly on wheat. In Iran, where many cereal fields are infested by this weed, not enough attention has been focused on the cereal crop yield losses, caused by this weed. A study of competition of wild oat with the winter wheat cultivar "Bezostaya" was conducted during the winter of 1990-1991, under irrigated condition, at Mashhad, in north-east Iran. In addition to decreasing fertile tiller number, infestations of more than 90 wild oat plants per m2 decreased number of kernels per spike, kernel yield per spike, and individual kernel weight, for wheat tillers significantly (a=5%). However, main stem yield components were not significantly affected. Furthermore, while biological yield decreased by approximately 10% (1285 kgha-'1, the grain yield decreased by 29% (1430 kgha-'1, when wild oat density was 141 plants per m2.