In Georgia, geneticists found that the gene variant called Cell Size Regulator is responsible for the size of various cultivated and wild tomatoes. They pinpointed the CSR gene that regulates how large or small the tomatoes’ individual cells are, which determines the tomatoes’ total size and if it will become a big beefsteak tomato, or tiny salad grape tomato. The gene is mutated in cultivated tomatoes compared to wild tomatoes and took thousands of years of farmers specifically choosing plants that had large fruit and strong structural support for the heavier fruit.
Professor Esther van der Knaap, a professor at the Institute of Plant Breeding, Genetics and Genomics at University of Georgia told Newswise, “The knowledge of the gene will now open up avenues of research into how fruit size can be increased further without negatively impacting other important qualities such as disease resistance and flavor.”