Abstract
The objectives of the investigation were to identify competitive traits in cereal species in order to contribute to development of a methodology for evaluation of cereal genotypes for their competitive capacity against weeds, which is important for organic breeding aims. The investigation was carried out with spring barley, spring oat, winter triticale and winter wheat genotypes in organic crop rotations in two different locations. Relations between crop traits and weed dry weight were evaluated by Pearson correlation coefficients. The results stressed the significance of some crop traits for cereal competitiveness against weeds for organic breeding purposes: (i) growth habit, canopy height, and crop development rate for spring barley; (ii) crop development rate for spring oats; (iii) winter hardiness and the coefficient of tillering for winter triticale, and (iv) winterhardiness, the coefficient of tillering, the number of productive stems, crop canopy and plant height for winter wheat. It coud be useful to include measurements of crop ground cover for estimating competitiveness of cereal species against weeds