An experiment was conducted to determine traits related to biomass quality and quantity of a few wild populations of a new bioenergy grass species - Elymus elongatus (tall wheatgrass). Four wild populations of tall wheat grass and one cultivar 'Szarvasi-1' were evaluated during three years in a field experiment. Plant morphological traits, biomass and seed yield were examined as well as analyses for biomass quality features (heating value, chemical composition of biomass and ash content) were also performed. Variation of examined traits was described in tested populations. Leaf dimensions (width, length and area) were significantly and negatively correlated with some biomass quality features (heating value and Hydrogen contents). Traits as number of generative stems, thousand seed yield and seed yield per plant were positively correlated with ash and sulphur contents. Selection procedure in tall wheatgrass for bioenergy purposes should take into account short and narrow leaves, short seed heads and high biomass yield as potential indicators of relatively high heating value. Intensive selection for high biomass yield without taking into account the weight of other features may result in unwanted ash and sulphur concentration in the biomass. (C) 2017 Elsevier Ltd. All rights reserved.