A prospective research on the duality between morphological traits and plant competitive abilities: the case of weed species and wheat.

Competitive abilities of plants were interpreted by measuring their morphol ogical traits in interspecific competitive cultivation conditions. Measurem ents were realised by a comparative approach with interspecific cultivation of fourteen arable weeds growing with a domestic species cultivated at a l arge scale: the winter wheat (Triticum aestivum var Darius). Results show t hat arable weeds characterised by an important biomass and allocation of bi omass to the stems are responsible for a decrease in wheat biomass, and for the ear, a decrease in height, biomass and number of seeds. These results are discussed in view of predicting competitive abilities of arable weeds w ith a simple method and for the conservation of arable weeds since some of them are among the most threatened species of the European flora. (C) 2001 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.