The allocation of sugars from leaf to fruit is a major determinant of tomato yield. This process consists of numerous transport and metabolic steps; all regulated by a multitude of feed forward and feedback control mechanisms. This complex regulatory system ensures that carbon acquisition in source leaves is balanced and integrated with plant growth and development, which ultimately determine agricultural productivity. In our work we use the leaf starch-to-sugar ratio as a metabolic index of whole plant carbon status. A single starch granule consists of millions of efficiently packed sugar molecules, and the flux of sugars in and out of the granule in the leaf may affect the sugars available for export to the fruit. We used this ratio as a proxy to identify lines altered in carbon allocation in a biochemical screen of a large proprietary collection of transgenic tomatoes. These lines were genetically engineered to each ectopically express 1 of 1700 Transcription Factors (TF) cloned from Arabidopsis. Our hypothesis was that TFs involved in controlling or integrating carbon allocation with yield, harvest index or fruit quality could be selected from this population based on changes in leaf starch. Three lines so identified were subjected to careful eco-physiological measurements to evaluate how growth and development may have changed as well as important agronomic traits