The plant I’m discussing today is the highest produced crop in the United States, is used
for things from feeding cows to making sweeteners, is in the grass family, and was domesticated
thousands of years ago.
If that, or, ya know, the video title, weren’t enough of a hint, I’m talking about corn.
Corn, also known as maize, was domesticated from a plant called teosinte, somewhere between
6,000 and 10,000 years ago.
Teosinte is rather unlike the tasty corn we’re used to.
It’s ears are small and tough, with only a few kernels.
The plant itself is bushy and sprawling, unlike the neat lines of tall corn we know today.
So maize is very different from its ancestor, so much so that at first botanists didn’t
believe they were related.
It wasn’t until genetic analysis showed the similarity between the two plants that
the relationship became apparent, along with other analyses, like looking at phytoliths.
Phytoliths are microscopic deposits of silica or calcium oxalate that accumulate between
the cells of the plant.
They vary in shape depending on the species of the plant, and survive thousands of years,
even after the plant is long gone.
So scientists can look at sediments and analyze the phytoliths, identifying whether domesticated
maize was present during a particular time period.
This was one of the ways they determined that corn is an ancient crop.
Basically, they used tiny silica fragments from thousands of years ago to learn about
corn.
Science is wild.
Maize was likely domesticated in what is modern-day Mexico, by ancient farmers who skillfully
and selectively bred wild maize.
Years of breeding yielded modern-day maize, scientific name Zea mays.
It is a grass, so it is in the family Poaceae, and it grows several meters tall.
Its flowers come in two varieties: male flowers, which grow at the top of the plant and are
called tassels, and female flowers, which are halfway down the plant and called the
ear.
They have long styles called silk, which may be familiar to you from husking corn.
Each ovule on that ear has the potential to become a corn kernel, as many as a thousand.
But first, that ovule must be fertilized!
I talk about pollination a lot on this channel, but maize is one of those plants that doesn’t
require pollinators to bear fruit.
Instead, the tassels produce huge amounts of pollen that are carried on the wind, meaning
those large fields corn are perfect for pollination.
Once fertilized, corn cobs form from the ear, yielding the delicious corn we know so well.
And corn is used for far more than human consumption.
In fact, most corn produced goes toward livestock feed.
It’s also used to produce ethanol, and the famous high-fructose corn syrup.
I mentioned that corn is the most dominant crop in the United States; every year, close
to 100 million acres of corn are planted.
So corn is big business.
And much of the drive for more corn and higher yields is caused by the ethanol industry.
In addition to its economic importance and long history, corn is well known for something
else: it’s prominence as a GMO.
A GMO is a Genetically Modified Organism, aka an organism that has had its genes altered
to accomplish a specific goal.
In many cases this is done by adding the gene from one organism to another, to help with
things like pest resistance, drought tolerance or chemical treatment resistance.
There are many GMO varieties of corn.
As of 2015, 33 varieties of it were approved for production in the US.
One example of these many, many varieties is Bt corn, which was engineered to be resistant
Lepidopteran larvae, like the European Corn Borer, Ostrinia nubilalis.
These hungry caterpillars can destroy corn crops, by chewing through the stalks, leaves
and fruit of the plant.
Bt corn has been engineered to contain a contain from a soil bacterium, Bacillus thuringiensis.
These gene allows the corn to produce crystal protein, a toxin to Lepidopterans and some
other groups of insects, making it resistant to the busy mouths of larvae.
Like I said, this is only one example of a trait that has been engineered into GMO corn.
Some varieties have more than one trait added in, making them a “stacked” variety.
Adoption of GMO crop plants have been skyrocketing.
Between 2000 and 2013, usage of GMO corn went from comprising less than 10% of the acreage
in the US, to over 80%, depending on the variety.
I’ve you’d like more thorough information about the use and analysis of GMO crops, I
encourage you to check out some of my sources in the description!
And there you have it, a brief primer on corn, the world’s top crop.
This video is the first in a series I'm calling Big Agriculture where I'll be going over lots
of different crops that are extremely important in the world.
That'll include rice, coffee, all sorts of things, if there's a crop you'd like to hear
about, please do let me know about it in the comments.
If you'd like to see more videos in this Big Ag series, please hit the thumbs up and subscribe
to my channel.
Again, if you have any questions, throw those in the comments, I'd love to hear from you.
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Thank you so much for watching, I'll see you next week.