Garden tomatoes belong to the plant species Lycopersicon esculentum. They descend from wild, inedible tomatoes, about the size of a cherry tomato, native to Peru and northern Chile. These wild ancestors of the modern world's most popular vegetable migrated via birds or animals to Central America, where indigenous people cultivated them and began to breed larger-fruited varieties with a bright red color.
Currant tomatoes, Lycopersicon pimpinellifolium, relate closely to garden tomatoes and the wild tomatoes of Central America, according to Kansas City horticulturalist and tomato breeder Keith Mueller, who runs The On-line Tomato Vine. Currant tomatoes bear small fruit about a 1/2 inch in diameter. Most fruits are red, but yellow varieties also exist. Currant tomatoes feature smooth stems, and stems lack the hairs found on garden tomato plants. Current tomatoes have been crossed with garden tomatoes to add resistance to diseases including bacterial and fusarium wilt. Also known as Wild Florida Everglades tomatoes, their seeds are available from boutique seed companies, and the plant is drawing interest due to its high levels of lycopene, an antioxidant with health benefits.
L. Esculentum Complex
Several members of the L. esculentum complex have provided sources of pest resistance in the cultivated tomato. None produce edible fruit. Its members include L. cheesmanii, endemic to the Galapagos Islands; L. chmielewskii, found in high, dry Andean valleys; L. parviflorum (also called L. neorickii), found in southern Ecuador and Peru along rocky roadsides; two types of L. hirsutum, found in central Ecuador and central Peru on the western slopes of the Andes; and L. pennellii, grown from northern Peru to northern Chile on dry hillsides and sandy areas. The currant tomato also belongs to this complex.
L. Peruvianum Complex
Two species, L. chilense and L. peruvianum, belong to the L. peruvianum complex. L. chilense, native to parts of Chile and southern Peru from sea level to altitudes of 3,300 feet, produces small green fruit. Crosses with the garden tomato, while tricky to achieve, have conferred some nematode resistance and a gene that resists tobacco mosaic virus. L. peruvianum produces slightly larger green fruit and grows in both coastal and high-elevation forms in Peru and Chile. While this species shows resistant to blights, molds and nematodes, most crosses between L. peruvianum and garden tomatoes fail due to incompatibility.