Fruit Growth in Tomato and Its Modification by Molecular Breeding Techniques

The fruit is a specialized organ which results from the development of the ovary after successful flower pollination and fertilization and provides a suitable environment for seed maturation and seed dispersal mechanisms. Due to their importance in human nutrition and their economic inference, fleshy fruit species have been the subject of developmental studies, especially using tomato (Solanum lycopersicum Mill.) as a model species due to its favourable biological cycle and all the available genetic and molecular resources. Tomato fruit growth results from the interplay between cell division and cell expansion. These two developmental processes are under the control of complex interactions between internal signals (due to hormones) and external factors (carbon partitioning, environmental influences), which altogether contribute to the establishment of crucial determinants for fruit quality such as the final size, weight and shape of fruits as well as the organoleptic and nutritional traits of the ripe fruit. This chapter aims at describing recent advances in the knowledge of molecular breeding applied to modify tomato fruit growth.