Tef is the most important crop among cereals in Ethiopia. Information on the natural genetic variation of the crop would be useful for the genetic improvement. Hence, the current study was designed to determine the genetic variability and heritability of selected tef core germplasm using morphological traits in a population collected from different origins in Ethiopia. A total of nine populations were field evaluated for 17 morphological traits using a 9 × 9 simple lattice designs for 81 genotypes at Debre Zeit during the 2021 main cropping season and off-season. Most of the population of tef showed significant differentiation across 17 traits, except days to heading, peduncle length, and number of fertile tillers of tef plants in the main season, and except grain yield/panicle, days to heading, panicle length, peduncle length, number of total and fertile tillers, lodging index, and harvest index among all populations in the off season. The population cluster distance values obtained between clusters 1 and 2 showed relatively high inter-cluster distance. This study shows the range of PCV is 4.6–109.8 for the offseason and 8.6–54.7 for the main season, and the GCV range is 3.7–88.9 for the offseason and 7.1-45.2 for the main season. Heritability (h2B) estimates ranged from 60% - 78% in two seasons. This all have good information for selection to improve tef productivity

Keywords: Population, Tef Germplasm, Differentiation, Cluster, Heritability