Tomatoes are a familiar sight in kitchens and gardens worldwide, valued for their versatility and flavor. While today’s varieties come in many sizes, shapes, and colors, their original forms differed remarkably from the plump, red fruits we commonly encounter. This journey from ancient beginnings to modern diversity reflects natural evolution and human influence.
The Wild Beginnings
The earliest tomato ancestors originated in the Andean region of South America, primarily Peru and Ecuador, with related varieties in Chile and Bolivia. These wild plants, Solanum pimpinellifolium (“pimps”), produced fruits that bore little resemblance to modern cultivated tomatoes. They were exceptionally small, often compared to peas or blueberries, typically weighing around one gram.
Wild tomatoes were orange or yellow when ripe, sometimes pale green-white with purple flecks. These sprawling vines, one to three meters tall, needed natural support. Despite their small size, these ancestors were hardy, adapting to diverse environments from arid deserts to humid lowlands and chilly alpine regions.
Early Cultivation and Transformation
Early human cultivation in Mesoamerica, notably by the Aztecs and Mayans, began the wild tomato’s transformation, with domestication evidence from 500 BC or 700 AD. Farmers selected for desirable traits, altering its appearance. This conscious selection increased fruit size, moving beyond tiny wild forms to varieties resembling today’s cherry tomatoes.
Early cultivated tomatoes, though smaller than many modern types, exhibited a range of colors, including red, yellow, and purple. The Nahuatl word “tomatl” (“plump fruit”) indicates increased size was an early cultivation focus. When Spanish explorers introduced tomatoes to Europe in the 16th century, they were met with skepticism due to their botanical relation to poisonous plants, often grown as ornamental curiosities rather than food.
The Modern Tomato: A Story of Diversity
After introduction to Europe and global spread, tomatoes diversified extensively, leading to thousands of cultivars. Modern breeding expanded sizes from tiny currant tomatoes to large beefsteak varieties, with cultivated fruits growing up to a thousand times larger than wild relatives. Genetic factors like the fw2.2 gene and fas loci increased fruit size by influencing cell division and seed chamber number.
Contemporary tomatoes display a wide range of shapes, including round, oblong, pear, and ribbed forms, with genes like ovate contributing to these appearances. Beyond red, modern tomatoes come in yellow, orange, green, purple, and striped varieties. Fruit color genetics involve carotenoid pigments (lycopene for red, beta-carotene for orange) determining hue. While intensive breeding for uniform red color and yield sometimes reduced flavor, overall genetic diversity in cultivated tomatoes increased since the 1970s. This expansion is due to introducing beneficial traits like disease resistance and enhanced fruit quality from wild relatives into cultivated lines.