Evaluation of Wheat Cultivars Competitiveness Against Weeds Based on Different Traits and Indices

In sustainable agricultural systems and healthy crop production, using of high-competitiveness cultivars is an easy and inexpensive method for weed management. Therefore, in order to study of competitive ability of 25 wheat varieties against weeds and identification and introduction of wheat cultivars with high competitiveness to use in crop breeding, an experiment was conducted using randomized complete block design with three replications in natural conditions in the university of Mohaghegh Ardabili field. The results showed that there was a difference more than 10 and 7 times between the lowest and the highest initial dry weight and the initial cover of wheat cultivars, respectively. The lowest (162.3 plant.m-2) and the highest (683.3 plant.m-2) weed density were observed in Ofogh and Orum cultivars, respectively. The difference between the lowest and the highest weed dry weight was more than 3 times. The results showed that weed dry weight had a negative correlation with the initial wheat dry weight (R2= -0.55**) and the initial wheat cover (R2= -0.70**). In competition with weeds, yield loss of wheat cultivars was between 3.22% in Sivand cultivar to 68.98% in Shiraz cultivar, which had a close relationship with weed dry weight. Cultivars showing high tolerance and competition index showed lower yield loss. This finding showed that wheat cultivars have a difference in CI (competitive ability) and WITI (weed interference tolerance index) and this feature can be used for non-chemical weed management programs.