In order to study genetic variation on forage and seed yields and their components among 12 varieties of white clover (Trifolium repens L.), a randomized complete blocks design with three replications was conducted over two consecutive years in Karaj, Iran. The data were collected for leaflet size, internode length, petiole length, canopy height, stolon density, internode thickness, persistency, head density, head per stolon, floret per head, seeds per floret, 1000 seed weight, seed yield and dry matter yield. Results showed significant differences between the genotypes for all of the traits except for head density and thousand seed weight. The varieties of Alice, Huia, Chiftan and Aran with average values of 14.2, 12.8, 12.2 and 11.8 tha^-1 produced higher forage dry matter yield. For seed yield Alice and Mikanova with average values of 148.7 and 122.4 kg h^-1 had the highest seed production per year, respectively. The results of correlation analysis showed positive and significant relationships between forage yield and canopy height, leaflet size, stolon density, petiole length and persistency. Seed yield had positive relationships with both 1000 seed weight and floret per head.
Using principal components analysis, the first three independent components accounted for 80% of the total variation. The first principal component indicated that forage dry matter yield, canopy height, head per stolon, petiole length and persistency were the important characters for classification with 52% of the total variation. Seed yield, floret per head and thousand grain weight were the enetial characters in the second component. Based on the results, it was suggested that components 1 and 2 could be known as forage yield and seed yield. Based on Ward Cluster Analysis, entries were divided into 3 groups. Accessions in cluster 1 (Huia, Chiftan and Aran) and cluster 2 (Alice, Mikanova and Avoca) averaged well above the overall mean for forage dry matter and seed yield, respectively.