Tomato’s Genetic Secrets Are Peeled Away

Scientists have made a genetic map of the tomato. Tomatoes are second only to potatoes as the world’s most valuable vegetable crop. Eight years of work went intomaking the map, or genome. Three hundred scientists around the world took part in the project to sequence the tomato’s DNA code. 

Giovanni Giuliano, a researcher in Italy, is part of the Tomato Genome Consortium. He says they started as ten countries and now have fourteen. Having the tomato’s genetic map will help growers who are always trying to produce a better tomato. Mr. Giuliano says they now know not only what genes are there, but their order. Researchers published the genome of a tomato used by Heinz, the American food company famous for its tomato ketchup. Ketchup is a thick sauce used on hamburgers, hot dogs and other foods. 

Heinz’s research manager, Rich Ozminkowski, says the company knows what it wants in a tomato. “Traits like sugars and, for Heinz, viscosity, or the juice thickness, and the redness of the tomatoes are all very critical traits for us,” he says. Those are all controlled by a lot of different genes within the tomato. Mr. Ozminkowski says genome sequencing takes away much of the guesswork for breeders of tomatoes or other crops that have been mapped. In his words, “By having the genome information, we can pick out those tomato plants that have more of those genes.” Until the late nineteen sixties, the tomatoes that Heinz used to make ketchup often cracked open on the vine after a heavy rain. Heinz wanted to to develop a variety that would resist that cracking. Breeders used the traditional methods of mating generations of different varieties. 

The tomatoes they were trying to develop not only had to resist cracking. They also had to resist disease. And they had to be easy to harvest mechanically. Finally the company came up with the tomato it wanted, called the Heinz 1706. Mr. Ozminkowski says the job would have been much easier if there had been a genetic map to follow. There were no genetic tools at the time. But the work today is not just about making better ketchup. Climate change may force many crops to adjust to new conditions. And Mr. Ozminkowski says researchers are already using the new genetic tools to help fight new plant diseases. The researchers published the tomato genome in the journal Nature.