Isozyme variation was studied to determine genetic relationships among 563 accessions of Musa, including diploid (AA and BB), triploid (AAA, AAB, and ABB), and a few tetraploid (ABBB) clones from Asia and the Pacific. Several open-pollinated seedling progenies of wild, diploid M. acuminata and M. balbisiana were also studied. Cryogenic preservation of leaf tissue in liquid nitrogen allowed sampling of a wide array of germplasm from Papua New Guinea and several Pacific Islands without transporting propagules which are subjected to quarantine regulations. Electrophoretic variation was recorded in three enzyme systems, MDH, PGI and PGM. In total, 52 distinct electromorphs were identified among 192 different isozyme phenotypes (zymotypes). Multivariate analyses of the data clearly differentiated the major genome groups and revealed patterns of association within groups. The isozyme data suggest that the genes contributed by the M. acuminata genome to the triploid Pacific plantain AAB subgroup are similar to those of the acuminata/banksii complex of Papua New Guinea. It is likely that the Pacific plantain subgroup, including the Hawaiian Maoli, POpO'ulu and Iholena cultivars, originated in Papua New Guinea/Melanesia, rather than in Asia or the Malay Archipelago.