ITFN Banana - Name, Taxonomy, Botany

The cultivated banana is often listed in botanical references as Musa x paradisiaca (Musaceae), although it is actually a complex hybrid derived from two diploid Asian species, M. acuminata and M. balbisiana. Musa acuminata is a species native to the Malay Peninsula and adjacent regions and is thought to have given rise in total or in part to all edible banana varieties. Musa balbisiana is found from India eastwards to the tropical Pacific. This hybridisation probably occurred as Musa acuminata plants (2n genome = AA) were increasingly cultivated over the distributional range of Musa balbisiana (2n genome = BB). Although the Musa acuminata cultivars were sterile because of being seedless, they did produce fertile pollen.

Common cultivated bananas are sterile usually triploid (3n) with three sets of chromosomes triploid and they are products of ancient hybridization between diploid and tetraploid species. Musa species are grouped according to “ploidy,” the number of chromosome sets they contain, and the relative proportion of Musa acuminata (A) and Musa balbisiana (B) in their genome. Most familiar, seedless, cultivated varieties (cultivars) of banana are triploid hybrids (AAA, AAB, ABB). Diploids (AA, AB, BB) and tetraploids (AAAA, AAAB, AABB, ABBB) are much rarer; the latter essentially being experimental hybrids. Fruits of cultivated Musa species are typically sterile or have extremely low fertility. They produce fruit pulp without pollination and fruits lacking seed (i.e., they are parthenocarpic). Although sterility and parthenocarpy are important factors that contribute to the desirability of banana fruits, sterility has impeded progress in breeding programs. Through natural somatic (vegetative) mutation, hybridization, and selection over many thousands of years, considerable genetic variability has arisen within the cultivated bananas, giving rise to more than 1000 varieties worldwide.

Plantain and banana cultivars evolved by natural hybridization between the two species M. acuminata (contributing genome A) and M. balbisiana (contributing genome B). All plantains and almost all important bananas are triploid (2n = 3x = 33 chromosomes). Plantain and banana are monocotyledonous plants, belonging to the section Eumusa within the genus Musa of the family Musaceae in the order Scitamineae.There are five taxonomic sections in the genus Musa, two of which contain edible bananas.