In alfalfa (Medicago sativa) regeneration is genotype-specific . In order to study the genetic control of somatic embryogenesis and to constitute a synthetic cultivar characterized by its high regeneration ability, 2 embryogenic plants selected from the cv . Adriana were selfed, intercrossed and also crossed in both directions with 5 nonembryogenic genotypes of the same cultivar . Progenies of all crosses were scored for their regeneration ability and results indicate that somatic embryogenesis is under the control of 2 dominant loci . However some non-embryogenic genotypes prevent regeneration when crossed with embryogenic ones and this characteristic is not under the control of a single dominant gene . When plants chosen for their capacity to regenerate within Fl and S1 progenies were freely intercrossed the regeneration efficiency dropped to 2% (1 plant out of 50) . This result indicates that if the genetic background of the population is changed the regeneration is greatly affected and therefore some other mechanism could play a role in determining plant regeneration