in order to diversify the maize germplasm utilized in the breeding work conducted at the instituto agron？mico, at campinas, s？o paulo, brazil, efforts were made to obtain corn samples from the most diversified origins. seeds of numerous varieties, inbred lines and hybrids were introduced and their performance observed under local conditions. until 1951, a total of 1405 samples were introduced, most of them being derived from various parts of brazil. from the united states, colombia, peru, bolivia also numerous samples were obtained. recently, single crosses from colombia, and mexican inbred lines crossed to brazilian single hybrids, were introduced, and are being tested under local conditions. yellow flint and dent varieties were tested in trials conducted at campinas, ribeir？o preto and pindorama. the best ones were : 1-catêto, 333-creóle yellow flint and 417-assis brasil among the yellow flint and 373-itaici and 986-tuxpan, among the yellow dent varieties. plants from more than 50 distinct varieties were selfed to get inbred lines. lines from about 20 varieties are still available. most of these were derived from catêto, some having now been selfed for 20 generations. l. 483 is the most outstanding one, as it has excelent agronomic features and high combining ability. from tuxpan the line l. 94-956 was obtained in vi？osa, minas gerais. in the years 1941 and 1942, 153 inbred lines and many hybrids were introduced from the united states. their performance is not satisfactory under local conditions, as they are too early, the ears having poor husk protection.