Every single naval orange comes from one original tree. Around 1915, an orange farmer is Brazil discovered that one of his trees produced oranges with no seeds. This was a freak mutation with a superb benefit for human consumption, but left no means for creating offspring. So branches were taken from this tree, and graphed onto normal trees. These branches would grow, until their branches could be harvested, and replaced on other trees. Nearly 100 years later, that is the same method used to produce over 50 Billion naval oranges world wide every year.
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