DOI link for Introduction
Despite its long history, the origin and evolution of banana is still regarded as speculative. Perhaps, the main reason for this is that bananas do not fossilize. Some of the thoughts on the origin of banana are changing as new data, especially from phytoliths, which are highly durable pieces of silica that form in plant cells, and molecular research, accumulate. Some new ideas on the early history and origin of bananas are described by Lejju et al. (2006) and De Langhe et al. (2010), respectively and references therein. However, it is accepted that bananas originated in the natural forests of Southeast Asia and the western Pacifi c region where wild inedible, seeded, diploid species (Musa acuminata) are still extant (Robinson 1996). This region is considered as the primary center of Musa diversity on the basis of Vavilov’s (1935) assumptions that important crop plants originated in those regions in which the largest number of varieties can be found in the wild. Recent genetic studies have confi rmed that the wild seeded Musa acuminata ssp. banksii F. Muell., was domesticated in New Guinea and then dispersed to Southeast Asia (Lebot et al. 1993; Lebot 1999). All edible bananas, except for a small group called “Fei” bananas, are thought to be derived from inter-and or intra-specifi c hybridization from two wild diploid (2n = 2x = 22) species, M. acuminata Colla and M. balbisiana Colla whose genomes are designated AA and BB, respectively (Simmonds 1962). The morphology of many banana varieties considered to have originated from crosses between the A and B-genome donors shows a bias towards the A or B phenotype and does not correspond to the simple genome formulas proposed by Simmonds and Shepherd (1955). This may indicate that the origin of cultivated banana varieties was not a single-step affair and that the domestication involved a set of backcrosses and human selection leading to a modern-day crop (De Langhe et al. 2010). The idea that selected plants grown by early humans produced seed progeny after backcrossing is supported by the observation of residual fertility in most of clonally propagated banana varieties (De Langhe et al. 2009). New ideas on the origin of present day hybrid bananas are expressed in Boonruangrod et al. (2008, 2009). There are a number of subspecies in the Musa acuminata complex.