The Corn Field Weed

Our favorite Thanksgiving foods are all of North American origin.  Turkey, potatoes, sweet potatoes, pumpkins, most varieties of green beans, and cranberries were unknown in Europe and Asia before Christopher Columbus made first contact with Native Americans.  Without the contribution of Native American agriculture our culinary repertoire would be destitute, also lacking corn, chocolate, vanilla, peppers, and perhaps most importantly, tomatoes.  Tomatoes originate from a plant that grows wild in South America–Solanum peruvianum.  It grows at mid-elevations where the climate is not too cold nor too hot.  Unlike its cultivated descendent–Solanum lycopersicum–the wild tomato is resistant to disease and insect infestation.  Some individual plants even exude a sticky substance on their leaves that traps insects and stops them from defoliating the plant.

Ripe wild tomatoes.  Some varieties of modern cultivated tomatoes are green when ripe.  A green color in ripe tomatoes is considered a primitive trait.

I harvested these Cherokee purple tomatoes late last June from my garden.  They are an heirloom variety, meaning they produce true to seed.  Most tomatoes sold in grocery stores are hybrids.  Despite garden catalogue propaganda, heirloom varieties are no better tasting than hybrids.  I also grew Better Boy hybrids, and they  tasted better.  In previous years the Cherokee purple tomatoes tasted better than the Better Boys.  The variation in flavor is influenced by soil nutrients, sunlight, and weather as much as by variety.

Native Americans probably first found wild tomatoes growing as weeds in their corn fields.  Good quality fruits were seasonal and rare in this region then, explaining why the early Peruvians would make a trial of eating these sour and bitter fruits.  Occasionally, they found individual plants that produced more palatable fruits, and the seeds of these were saved and planted on purpose.  About 2500 BP the Peruvian Native Americans colonized or conquered Mexico and carried seeds of this plant with them.  This is where cultivation led to the development of what we would recognize as a modern tomato.

A variety of heirloom tomatoes–all descended from the species of small green wild tomato pictured above.

Horticulturalists still use wild tomatoes for crossbreeding with cultivated tomatoes to help strengthen disease and insect resistance.  As every backyard gardener and truck farmer knows, tomatoes are inbred weaklings, susceptible to disease.  Almost every tomato plant I’ve ever grown eventually develops some sort of blight.  Horticulturalists hope to combine disease resistance of wild tomatoes with the good taste of cultivated tomatoes.

Tomato horn worm (Manduca quinquemaculatata).  It’s actually the larva of a large moth.  I once read an article written by an idiotic gardening advice columnist who suggested gardeners only needed to look over their gardens once a week.  A few of these hornworms can defoliate an entire row of tomato plants in about 3 days.  I check daily and crush them on sight.

The solanum genus also includes the Irish potatoes (Solanum tuberosum) and eggplants (Solanum melongena). The fruit of some other plants in the Solanidae family, such as peppers and husk tomatoes are edible, but others such as belladonna and nightshades, have poisonous leaves and fruit.  This explains why it took centuries for Europeans to develop an appetite for tomatoes.

Tags: Cherokee purple tomatoes, Solanidae family, Solanum lycopersicum, Solanum peruvianum, tomato hornworm, wild tomato