text: Picking and ripening To facilitate transportation and storage, tomatoes are often picked unripe (green) and ripened in storage with ethylene.
  A machine-harvestable variety of tomato (the "square tomato") was developed in the 1950s by University of California, Davis's Gordie C. Hanna, which, in combination with the development of a suitable harvester, revolutionized the tomato-growing industry. This type of tomato is grown commercially near plants that process and can tomatoes, tomato sauce, and tomato paste. They are harvested when ripe and are flavorful when picked. They are harvested 24 hours a day, seven days a week during a 12- to 14-week season, and immediately transported to packing plants, which operate on the same schedule. California is a center of this sort of commercial tomato production and produces about a third of the processed tomatoes produced in the world.
  In 1994, Calgene introduced a genetically modified tomato called the FlavrSavr, which could be vine ripened without compromising shelf life. However, the product was not commercially successful, and was sold only until 1997.
  Yield
  The world dedicated 4.8 million hectares in 2012 for tomato cultivation and the total production was about 161.8 million tonnes. The average world farm yield for tomato was 33.6 tonnes per hectare in 2012.