Gabe15

No one knows exactly how many different types there are, and the many complexities and issues with taxonomy make it difficult to even define what is worth being called "different". Some differences are very small, and some are very big, but for this question let's consider that any difference is a significant difference.

Of the wild bananas, there are approximately 70 published wild species, but a good deal more known but undescribed species, and of course an unknown number of unknown and undescribed species (as more new species are being found all the time, I think it's safe to assume this will continue for some time). Additionally, most wild banana species have a number of natural varieties which usually vary by location within a larger population. If we assume an average of 5 different forms of each basic species (which is probably rather conservative, given some species are known to have well over 10 known varieties), and there are about 70 species, 350 different wild bananas would be a reasonably estimation, but I think this number to be low in reality, maybe it's even closer 1,000 or more (why not?!). In addition, there are natural hybrids of wild species that occur in overlapping populations. And finally, there are wild species that have been domesticated for non-fruit use, but they are generally not regarded as domesticated plants, so there are many distinct varieties which are not really recognized or known by most scientists. Examples: Musa balbisiana, M. textilis and Ensete ventricosum all have many domesticated selections.

If you consider landraces, and nothing created from breeding programs, the estimations vary from about 300 to 1,000. My personal estimation is somewhere in the 2,000-4,000 range just for landrace cultivars. Even though landrace cultivars are inherently known now or in the past by someone, no one person or organization has seen and documented them all, and more are still being found and recognized by scientists.

If you consider the products of breeding programs, the basic question is made extremely complex, because there have been literally tens of thousands, likely even hundreds of thousands of genetically unique banana plants created. Of course only a small fraction have been the final, useful products of the breeding programs, but if we are taking the original question literally, then I suppose they must be counted and considered. Also, many of these breeding lines are quickly lost or thrown out, so there is some difference between all the banana varieties that exist versus all that have ever existed.

So in summary with low estimates and high estimates and depending on viewpoint of "different"...

Wild plants: 70-1,000
Landrace cultivars: 300-4,000
Breeding lines:100,000+
Others: who knows...
Grand total: 370-infinity.....no one knows the exact number, and due to breeding and improvement it's a constantly growing number, but we do there's a lot of bananas out there.

Note this is partially based on data, and partially based on my personal estimations and thoughts.

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Growing bananas in Colorado, Washington, Hawaii since 2004. Commercial banana farmer, 200+ varieties.