Genetic modification of food has happened for thousands of year. Tomatoes would still be the size of your thumb without genetic modification.
A 2012 study may mean tomatoes of the future could get that much better. They're big business, on the order of 15 million tons of the fruit for processing and fresh-market sales annually, so for decades food scientists in the tomato industry have selected varieties that are uniformly light green before they ripen, in order to produce tomatoes that can be harvested at the same time. But this characteristic is accompanied by an unintended reduction in sugars that compromises the flavor of the fresh fruit and its desirability for processing.