Tomatoes were probably first domesticated in the Andean region of Peru and Ecuador. From there, cultivation spread to Mexico, where conquistadors found them, returning with them to Europe in the seventeenth century.
In the years since, we have bred them to produce larger fruit, to resist diseases, and to retain their shape and color in neat supermarket pyramids. But the initial domestication event also selected an agriculturally advantageous trait—it slowed down the plant's circadian clock so it could thrive in the long sunny days of the new latitudes it found itself in.
Circadian clocks are present in all kingdoms of life. They function to coordinate organisms' metabolic and other activities with the external environment, notably the 24-hour light-dark cycle. Circadian clocks are known to regulate plant physiology and development and therefore almost certainly affect the agricultural fitness of crops; shockingly, they have not yet been intentionally manipulated.