Jennifer Schultz Nelson
Extension Educator, Horticulture
For me, after a dreary winter of tasteless cardboard tomatoes from the grocery store, the exquisite taste of a freshly harvested vine-ripened tomato is nirvana. I never gave much thought to the origins of the tomatoes I anxiously await each summer until I started graduate school.
As a new grad student, I was introduced to the world of wild tomatoes almost immediately, as a fellow lab member's project involved tomato breeding using wild tomatoes.
I expected to see plants that looked like tomatoes I had grown in my garden. Standing at the edge of the field, I knew I had a lot to learn.
They didn't look like any tomatoes I'd ever seen. The leaves were much thicker and wider, and their scent hung heavy in the air, much stronger than the typical garden tomato plant smell. Strangely, it was late August and I didn't see any tomato fruits anywhere.
What I didn't realize was that wild tomatoes are self incompatible. Pollen has to be transferred from one plant to another for successful pollination and subsequent fruit production. A closer look revealed small tomato fruits here and there, the lucky result of insects spreading pollen in the tomato blossoms. But they were as small as marbles, dark green, and hard as a rock. For this particular species, the fruits stayed green, and were inedible. There are also edible wild species that ripen to red, but stay very small compared to tomatoes grown today.
There are many different wild tomatoes, thought to be originally from Peru. All are from the genus Lycopersicon, a member of the Solanaceae family, which also contains potatoes. Take a moment to compare the leaves of tomatoes and potatoes, and the family resemblance is obvious.
Two key differences between wild and modern tomatoes are size and self-fertile flowers. Breeding efforts developed plants with flowers that successfully pollinate themselves as they open, and that produce fruits much bigger than their wild ancestors.