There are more differences in the genomes of two unrelated corn plants than between the genomes of a human and a chimpanzee (two species separated by 3.5 million years of evolution).
On the other hand, two unrelated human beings, members of the same species, have more than four times as many genetic differences as two unrelated heirloom tomatoes.
Corn vs. Corn > Human vs. Chimpanzee >> Human vs. Human >> Heirloom Tomato vs. Heirloom Tomato
Now the fact that any two human beings are more closely related to each other than either is to a chimpanzee should be obvious to anyone who gives it a moments thought.
I plan to poll my sections tomorrow to see how many of them would put corn and heirloom tomatoes in the opposite positions, but many have figured out my feelings about corn, so they’ll probably guess it’s a trap.