A process that is called “selective breeding†is sometimes used for bananas in order to make it so that they are resistant to certain insects as well as disease which can kill them off.
This process is also used to reduce the number of seeds which form when they are growing; it forms as a stringy-like material at the center of the banana and is responsible for forming an excessive amount of flesh around the fruit.
Normally bananas have large woody seeds which are located in the middle of them; however through recent selective breeding endeavors, this is becoming less and less of an issue.