117 Revista de la Facultad de Ciencias Agrarias - UNCuyo | Tomo 54-1 - Año 2022 Competition between beans and Urochloa plantaginea Rev. FCA UNCuyo. 2022. 54(1): 117-131. ISSN (en línea) 1853-8665. L. Galón et al. 1 Federal University of Fronteira Sul. Campus Erechim. Laboratory of Sustainable Management of Agricultural Systems. 99700-970. Erechim. Rio Grande do Sul. Brazil. *leandro.galon@uffs.edu.br 2 Federal University of Technology Paraná. Campus Pato Branco. Laboratory of Weed Science Research Centre. 85503- 390. Pato Branco. Paraná. Brazil. 3 Embrapa Clima Temperado. Department of Sustainable Cropping Systems. 96010-971. Pelotas. Rio Grande do Sul. Brazil. 4 Federal University of Pelotas, Campus Capão do Leão. Department of Plant Physiology. 96050-970. Capão do Leão. Rio Grande do Sul. Brazil. 5 State University of Montes Claros. Department of Agricultural Sciences. 39440-000. Janaúba. Minas Gerais. Brazil. Competitive ability of bean Phaseolus vulgaris cultivars with Urochloa plantaginea Capacidad competitiva de cultivares de frijol Phaseolus vulgaris con Urochloa plantaginea Leandro Galon 1* , Leonardo do Amarante 1 , Emanuel Luis Favretto 1 , Daniel Cristian Cavaletti 1 , Otilo Daniel Henz Neto 1 , Daiani Brandler 2 , Victor Miguel Senhori 1 , Germani Concenço 3 , Thais Stradioto Melo 4 , Ignacio Aspiazú 5 , Michelangelo Muzzel Trezzi 2 Originales: Recepción: 07/06/2021 - Aceptación: 21/02/2022 Abstract The objective of this work was to evaluate the competitive ability of carioca bean cultivars BRS FC104, BRS FC402, IAC Imperador, IAC Milênio, IPR Tangará, and SCS Riqueza in the presence of Alexandergrass (Urochloa plantaginea) in different proportions of plants in association. The experiments were carried out in a greenhouse in a completely randomized design with four replications. The treatments were arranged according to the proportions of beans and Alexandergrass plants: 100:0, 75:25, 50:50, 25:75, and 0:100 or 40:00, 30:10, 20:20, 10:30, and 0:40 plants per pot. The competitiveness of the species was analyzed using diagrams applied to replacement experiments and also through relative competitiveness indices. At 30 days after crop emergence, leaf area (LA), height (HP), diameter (DP), and shoot dry mass (SM) of the plant shoots were measured, as well as variables related to the physiology of the species. There was competition among carioca bean cultivars in the presence of Alexandergrass regardless of the proportion of plants, causing decreases in DP, LA and SM. Basically, there is competition for the same environmental resources between beans and Alexandergrass. Keywords Phaseolus vulgaris • weed ecophysiology • competitive interaction • replacement series