The origin of the cultivated tomato is somewhat unclear. Ethnobotanists and geneticists however have attempted to track down the centre of domestication. "The genus Lycopersicon- the botanical group to which the tomato belongs- is native to western South America, and only Lycopersicon lycopersicum var. cerasiforme, the wild cherry form of the cultivated species, has spread throughout Latin America and the New World Tropics. Second, the tomato was not known in Europe until after the discovery and conquest of America, descriptions and drawings first appearing in the European herbals of the middle and late 16th century. Third, these writings clearly reveal that man had been trying to improve the size of the tomato and the diversity of its shape and color. These achievements over the wild ancestors were almost certainly achieved by early man in America. Mexico appears to have been the site of domestication and the source of the earliest introductions, and the wild cherry tomato was probably the immediate ancestor." As a matter of fact, "the bulk of the historical, linguistic, archaeological and ethnobotanical evidence favours Mexico, particularly the Vera Cruz-Puebla area, as the source of the cultivated tomatoes that were first transported to the Old World. " Although the origin of the tomato is somewhat clouded, there is no doubt that the cultigen of today has had a long journey.
When the tomato finally made its way to Europe, the public responded with fear for several probable reasons. First, tomatoes belong to the family Solanaceae, which includes Datura and Belladonna - the deadly nightshade, among other poisonous species. The assumption was that tomatoes must be poisonous as well. Second, in Germany, because of its terrible smell, the tomato plant was rejected. The tomato acquired names like the "Devil's wolf apple." This great fear of toxicity of the tomato plant probably prevented its utilization for many centuries. Today, the toxicity of the Solanaceae family has been studied extensively, and it has been found that most of the species are posionous. Obviously Belladonna and Datura are among the more poisonous members of the family, but the potato plant is also quite toxic. Lycopersicon spp., which are less toxic than the other members of the family, contain tomatine, a toxic glycoalkaloid .
Many wild relatives of the tomato such as Lycopersicon esculentum var. cerasiforme, L. chilense, L. peruvianum, L. hirsutum, and L. pimpinellifolium are among the richest genetic pools available for cross breeding. Almost all of the effective resistances to virulent tomato diseases have been found from wild species of Lycopersicon and Solanum. Geneticists from UC Davis have been making trips to the Andes and Central America in search of new species since 1948. Since then, researchers have amassed a germplasm stock effective against over 42 diseases. "Few other crops are blessed with such extensive collections of wild forms and their derivatives." Not only are these wild relatives valuable sources of genetic material for disease control and prevention, but also for arthropod resistance, improving fruit quality, abiotic stress tolerance, and drought/cold resistance among many others.