Tomato domestication was more complex than previously thought
Tomatoes have been domesticated by native American cultures thousands of years ago. However, since very few tomato archaeological remains have been found, the precise history of this plant’s domestication remains a mystery. While some scientists claim that the domestication occurred in Mesoamerica, the region comprising Mexico and Central America, others argue that this process happened in Peru and Ecuador.
By analyzing the whole genome of 628 wild and cultivated tomato plants, a team of scientists led by the Polytechnic University of Valencia in Spain has discovered that the history of the American tomato is more complex than initially thought.
The genomic analyses revealed that, while most of the contemporary cultivated tomato is very similar to the wild Mesoamerican plants (Solanum lycopersicum var. cerasiforme), wild Ecuadorian and Peruvian species (S. pimpinellifolium) have also been involved in its domestication.
According to the scientists, the domestication process started with the Mesoamerican materials, which migrated southward to a region located between the foot of the Andes and the Amazonian rainforest in Peru and Ecuador called Ceja de Montaña. This initial migration was probably fast and most likely due to the emergence of commercial relationships between different Mesoamerican and Ecuadorian and Peruvian cultures.
More recently though, some of these plants, very similar to the ones still grown in Northern Peru and Southern Ecuador, migrated back to Mexico. Surprisingly, the vintage Yucatan tomatoes are more similar to the ones found in Ceja de Montaña than to their wild counterparts found in Mexico, suggesting that some wild tomatoes migrated southward and, then, went back as cultivated.
These voyages would change the tomato forever. Growers from Ceja de Montaña did not use pure Mesoamerican plants, but rather admixtures created by crossing the newly arrived plants with wild varieties from coastal Peru and Ecuador. This hybridization between Mesoamerican and Ecuatorial plants was necessary for the adaptation of northern tomatoes to the climate and latitude of Ecuador.
These complex movements between Mesoamerican and Ecuatorial territories were only the beginning of the tomato’s trip around the world. After being introduced in Europe in the 16th century by the Spanish conquistadores, many more different genetic varieties were and continue to be created according to various people’s needs, uses, and tastes. From a secondary crop used mainly to prepare sauces by some Mesoamerican populations, the tomato spread around the world and became one of the most famous and widely consumed vegetable.
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By Andrei Ionescu, Earth.com Staff Writer
