In this study, Musa species and cultivars with different ploidy levels and genomic constitutions were hybridized to estimate the efficiency of the hybridization process and the yield of hybrid seeds. The findings are as follows. The hybridization of ‘Dwarf Cavendish’ (a triploid) as the female parent with the pollen of Musa balbisiana (a species of wild banana) produced few hybrid seeds, and that of ‘Pei Chiao’ as the female parent with the wild banana yielded no hybrid seed. The hybridization between ‘Monkey’ and the pollen of diploid wild bananas had a seed–set rate of 8%–12% and produced 1–19 hybrid seeds. The hybridization between ‘Pelipia’ and the pollen of diploid wild bananas had a seed–set rate of 6%–50%. The hybridization of ‘Pelipia’ with M. balbisiana produced 1–219 hybrid seeds, 12–244 with M. itinerans var. formosana and 1–14 with M. textilis. The hybridization of M. balbisiana with M. itinerans var. formosana as the male parent (rather than as the female parent) produced seeds. Some of the hybrid seeds from the hybridization of triploid cultivars with the pollen of wild diploids were irregular or deformed in appearance. The hybridization of triploid cultivars with wild diploids as female parents produced more hybrid seeds, most of which were normal in appearance and some of them contained (a) no embryo or endosperm, (b) deformed embryos and no endosperm, or (c) deformed embryos and endosperms. Accordingly, the production of hybrid seeds does not necessarily indicate successful hybridization. The findings of this study may inform the selection of hybrid parents and banana breeding.