According to Official Guinness Records,
The most tomatoes harvested from a single plant in one year weighed 522.464 kg (1151.84 lbs). The tomato plant is at the Epcot Science project at Walt Disney World Company in Lake Buena Vista, Florida, USA. The harvest started on 24 May 2005 and ended on 20 April 2006. 32,194 tomatoes were harvested.
For a complete list of 2006 records, please visit 2006 Guinness Records in United States.