Alfalfa is the most important forage crop in the world for the improvement of which the presence of primary variation is the most substantial. In the present work, the situation of variability levels among 36 alfalfa genotypes was studied in a field experiment in the research farm of Bu-Ali Sina University with the evaluation of 9 traits in a completely randomized design in 2009-2010.Analysis of variances of data showed that the genotypes for all the studied traits were significantly different from each other. Genotypes of Lotus81, Feriken and Vernal were appeared to have the highest Forage dry matter yield. The results of the analysis of correlation of the studied traits indicated a positive and significant correlation between Forage dry matter yield and plant height and a negative and significant correlation with the ratio of leaf to stem dry weight at the probability level of 5%. In analysis to main components, about 79% of the total changes were confirmed by the first of the 4 main components. Based on cluster analysis, the genotypes were clustered in five groups. The genotypes in the first cluster had appropriate forage quality and the genotypes in the second cluster were superior concerning forage quantity.
