Considerable research has been directed towards the study for obtaining Medicago sativa varieties to be used for the production of proteic concentrates. For this purpose the behaviour of two lucerne populations was studied under different cutting regimes. During the period 1977-79 for each of the two populations, 1200 genotypes divided into groups of 400 plants were cut when their mean height reached 30, 45 cm and at flowering time. Green matter yield per plant at each cut, percentage of dry matter yield, protein content and number of surviving plants were considered.