Despite the importance of forage plants in animal husbandry, not much attention has been paid to the category of breeding and introduction of suitable forage plants in comparison with other crops at Iran. Therefore, the main objective of this study was to investigate Phalaris aquatica as a forage species in order to identify the desired genotypes for use in breeding projects. For this purpose, a study was implemented using 26 selected Ph. aquatica genotypes in a randomized complete block design with three replications in the research field of the Agricultural Biotechnology Research Institute of northwest and west region of the country in Tabriz at 2019-2020. The Ph. aquatica genotypes were examined in terms of morphological traits, seed and forage yield. The results of analysis of variance showed the existence of genetic diversity among selected genotypes. Cluster analysis classified the studied genotypes into two clusters. Considering traits such as yield and yield components, genotypes in the third sub-cluster can be a good choice for cultivation. Also, based on results of genetic distances study of the Ph. aquatica genotypes, the maximum genetic distance was obtained between the third sub-cluster and the fifth sub-cluster, which, if necessary, the genotypes of these two sub-clusters can be used in breeding programs in order to exploit their desirable genes. In the principal components analysis, four components were identified, which in total explained 84.3% of the total variance. In the first component, traits such as dry forage yield, crown diameter and canopy diameter, in the second component, only the leaf length and in the third component, traits such as number of days to flowering and number of days to pollination had the highest coefficients.
