The researchers studied different types of maize to see how well they combined with each other and with other testers. They found that some maize populations had better combining abilities than others, with Tuxpeno and Suwan1 showing higher general combining ability. Combinations with 50%-75% tropic germplasm had the highest yields when combined with certain testers. The inbred lines CML161 and CI44 were effective testers for local maize germplasm.