A three-year programme was begun in 2007 to develop a method for assessing the competitive potential of wheat varieties with respect to weeds and to encourage the adoption of this criterion in selection programmes. The first year of experiments made it possible to identify the most explanatory characteristics of the competitive potential of wheat (using Italian ryegrass to simulate weeds): height first, followed by ground cover and leaf habit. These factors are nevertheless not adequate for totally predicting the competitive potential of wheat varieties and, in particular, intermediate varieties for which wide variations were observed from one situation to another in our experiments. We are now waiting for the results of two additional years of experiments
