Competitive interactions between wheat (Triticum aestivum L.) and rigid brome (Bromus rigidus Roth): a replacement series study

Abstract

Bromus rigidus is increasingly recognized as a problematic weed species in cereal production of Mediterranean areas, especially under conservation agriculture practices. A better understanding of its interaction with wheat may provide new options for sustainable management. To this end, this study aims to evaluate the competitive interactions between this weed and four soft wheat varieties (Remax, Faiza, Bandera and Guadalette) in a controlled pot experiment using a replacement series design. Results showed clear differences in morphological and ecophysiological traits between the two species and among wheat cultivars. In fact, wheat exhibited a superior competitive advantage, based on relative yield and competitiveness ratio values. This performance may be explained by specific growth and physiological parameters, particularly plant height, leaf area, stomatal conductance, chlorophyll and nitrogen content. This clear competitive superiority is more remarkable for the Remax and Faiza varieties than for Bandera or Guadalette. Indeed, while Faiza and Remax showed a suppressive profile towards B. rigidus, the other two varieties showed a less aggressive but more tolerant character, which allowed them to maintain their yield without necessarily affecting the weed growth. Overall, these findings provide the opportunity to choose these aggressive wheat genotypes as a cost-effective strategy, especially under high infestation of brome or areas of herbicide resistance cases.

Keywords: Wheat, rigid brome, competition, replacement series