competitive characteristics of wheat cultivars in competition with japanese brome (bromus japonicus)

abstract a field experiment was conducted to study the competitiveness of wheat cultivars against bromus japonicus at sistan agricultural research station during 2003. the experimental design was a randomized complete block assigned in factorial arrangement of treatments with four replications. six wheat cultivars comprised two natives (old cultivars; boulani and kalak-afghni), and four new-released cultivars (chamran, hirmand, kavir, and hamoun) (as factor a) were grown in pure stand and in mixture with b. japonicus (as factor b). weed density was 100 plants m-2. the old cultivars were found more competitive than new-released ones. boulani was the most competitive cultivar, however, had the lowest yield. in contrast, kalak-afghani with a good competitive ability indicated the highest yield. cultivar hirmand with a low yield and the highest weed infestation was indicated the least competitive cultivar. the more competitive cultivars had more biomass, leaf area, plant height, tiller number, and grain yield than the less competitive ones in competition with b. japonicus.