Figure: Colourful mixture - Tomato breeding offers a wide variety.

© MPI-MP, S. Osorio Algar

To gain new insights into tomato breeding and their consequences, a group of researchers from China, USA, Bulgaria, and Germany analyzed the metabolic constitution and the genetic background of tomato fruits. In a paper published in the journal Cell, they presented an overview about the human influence on the chemical composition of a crop plant for the first time.

Tomatoes are from South and Middle America, where their wild relatives are small, and partly bitter tasting. Alkaloids are responsible for bitter-tasting compounds, and plants use them for protection against herbivore attacks. Domestication and modern breeding programs reduced the bitter tasting compounds of tomato and larger fruits were selected.

The research team analyzed and compared the genetic and metabolic composition of up to 610 tomatoes of different origins, said Professor Alisdair Fernie of the Max Planck Institute of Molecular Plant Physiology (MPI-MP). The comparison of wild and cultivated tomatoes is decisive here, because small berry-like fruits of the wild species were transformed into red tomatoes, which were nearly hundred times larger. The breeding process passed through two main stages. First, the plants were domesticated and secondly, they were improved. The researchers found that these two phases seemed to have had a different influence on the chemical composition of the fruit.

For more information, read the press release from MPI-MP.