As a result of breeding work carried out by the Sugar Cane Department along the years 1947, 1948 and 1949, quite a lot of seedlings had been obtained, after several selections. This considerable number of seedlings was then studied with the purpose of determining which of them could be qualified so as to be considered as new varieties. To this effect two series of experiments were conducted at the factories Santa Elisa, Tamoio, Ester and Pôrto Feliz, all of them on soil of the type «terra-roxa-misturada». The first series of experiments was established in 1954 having Co. 290 as control, a variety which was the most planted by then. After the second harvest in 1956, these experiments were brought to an end, since Co. 290 showed then a rather severe decrease in production so that it could no longer meet the conditions for which it had been used initially. Due to this, a second series had to be started where just those seedlings were used that had outstanding qualities in the first series. Thus, they were planted in 1957 at the same localities as the first series of experiments, but this time a design was used of a balanced lattice 5x5 with 6 replications. As controls were used the varieties CB 41/76, Co. 419 and CB 40/69 which were then the most recommended for the State of São Paulo. For each experiment three harvests were made, plant cane, first and second ratoons. From the results obtained it was found that the variety Co. 419 gave small yields pretty lower than those of CB 41/76 and CB 40/69; the seedlings known as 49/131, 48/65 and 47/31 showed in general rather high yields in comparison to the controls; S 47/13, in spite of its productions not being in all cases higher than those of the two CB controls, showed a high content in sugar, whereas on the other hand, S 49/3, although with the best productions in tonnage of cane, didn not satisfay with regard to its sugar content. The other seedlings under study did not deserve any interest. As new varieties just the following seedlings were considered: n.º 47/13, 47/31, 48/65, 49/3 and 49/131, receiving the prefix IAC.