In the period of 2004-2006, field trails were conducted at the New Valley Res. Station to evaluate the yield potential and genetic variances among alfalfa cultivas; a new Synthetic (Wady Syn.),  four promising populations ( Serw₁, Serw₂, Nitrogen fixation and salt tolerant ), three commercial varieties ( Siwa, Ismailia₁ and Ismailia₉₄) and a local cultivar ( Wady ). Twenty cuts were obtained during 2005 and 2006. The combined analysis of variance over two years indicated that Wady Syn. population ranked first for fresh and dry yields ( 72.3 t fed^-1 and 18.9 t fed^-1 ) and other studied traits significantly different from other tested cultivars. The commercial variety  Ismailia₉₄ ranked second ( 66.55 and 17.2 t fed^-1 ). Regarding  plant height, tillers and leaf to stem ratio (LSR), WadySyn. recorded the highest values (48.2 cm, 416.7/m² and 47.6 %) significant from Ismailia₉₄ which recorded 45.6 cm, 362.3 m² and 43.3 %, respectively. Significant positive correlation among either fresh forage yield or dry forage yield and other traits. The values of  genotypic coefficient of variation for fresh and dry forage yields revealed relative variations among the tested cultivars which were less influenced by environment. The environmental variation ranged from 4.4% to 33.3% and the genetic advance ranged from 3.9% to 14.5%.