Contemplating My Navel: A Quick History of Citrus

I like cooking seasonally, because I think it tastes better. Epicurious.com has a great seasonal eating map that’ll list everything at the farmers’ market, but of course this is Wisconsin and exactly nothing is growing outside right now.

What gets me through the dark cold winter is citrus season. Grapefruit is amazing this year (even if you usually don’t like grapefruit, try it this year–it was perfect weather for delicious grapefruit), satsumas are just past their peak but still sweet and juicy, blood oranges are here. And KUMQUATS!

Which got me to thinking, what is a tangerine anyway?

It turns out that this has been a surprisingly hot topic in the plant genetics community. Who knew? Recently, some researchers used DNA to figure out the ancient ancestors of all citrus (Fun For Science Nerds: amplified fragment length polymorphism analysis).

There was one really really old original citrus ancestor, those studies found. They also found that citrus is really good at hybridizing, or creating new species. There were three major speciation events that created lots of diversity a heckuva long time ago. The Great-Grandparents of Citrus were generated in a succession of speciation events occurring between 7.5-6.3 million years ago, again 5.0-3.7 million years ago, and then around 1.5-0.2 million years ago.

The three citrus ancestors are pummelo (it’s in the produce aisle), mandarin and citron (it looks like a big bumpy lemon). All modern citrus are descended from these three. Sweet and sour oranges are hybrids of mandarins and pummelos. Lemon and bergamot (the distinctive flavor in Earl Grey Tea) are a cross between citron and sour orange.

There’s evidence that people were cultivating citrus in China more than 2500 years ago, and it made its way to the Mediterranean about a thousand years ago. These days, the big bucks are in sweet and mandarin oranges grown in Brazil, the United States, China, Spain, Mexico, Italy, India, and Egypt (in order of amount grown). The chief orange-growing states in the United States are Florida, California, Texas, and Arizona, in that order.

The world production of all kinds of oranges is approximately 70,000,000 metric tons annually.

So now that you’ve read this far, I’ll tell you what a tangerine is. According to Tracy Kahn at the University of California – Riverside Citrus Collection, “The word tangerine is often used

interchangeably with the word mandarin but actually the term tangerine was coined for brightly colored sweet mandarins that were originally shipped out of the port of Tangiers Morocco to Florida in the late 1800s and the term stuck.”

-Reb Kilde, Fresh Lead

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