Weeds and their evolution

Abstract

That weeds are as old as agriculture is indicated by the finding of some obligatory weeds such as Lolium temulentum among cereal seeds from 3200 BC (McCreery, 1979). Weeds are undesirable companions of crop plants, reducing their yield and quality, and man’s attitude toward them has always been negative and considerable efforts have been made to eradicate them, evidently with only relative success. The continuous engagement with weed control and shifts in agricultural practices have been powerful enough to create in weeds changes of evolutionary significance. Before elaborating more on these changes, let us look at some of the biological and ecological properties of weeds.