Tomato, Chapter 1.

LABATE J. A., GRANDILLO S., FULTON T., MUÑOS S., CAICEDO A. L., PERALTA I., JI Y., CHETELAT R. T., SCOTT J. W. ET AL.

Genome Mapping and Molecular Breeding in Plants, Volume 5, Vegetables

Springer-Verlag

Lugar: Berlin Heidelberg; Año: 2007; p. 1 - 125

Tomato, Chapter 1 1.1 Introduction Tomatoes (Solanum lycopersicum) are consumed as either fresh fruit by themselves, in salads, as ingredients in many recipes, or in the form of various processed products such as paste, whole peeled tomatoes, diced products, and various forms of juices and soups. The tomato is a favorite garden plant in many parts of the world, an important source of vitamins and nutrients (see Sect. 1.14), and an economically important agricultural commodity (see Sect. 1.3.3). Tomato was among the first crops for which molecular markers (isozymes) were suggested for marker-assisted selection (MAS) in breeding (Rick and Fobes 1974; Tanksley and Rick 1980). Tanksley (1983) discussed the viability of using isozymes for MAS in tomato and concluded that DNA-based markers would probably be utilized for the next iteration of MAS in tomato. The most daunting challenge of effectively implementing MAS in cultivated tomato has been the low frequency of easily identifiable molecular polymorphisms within S. lycopersicum (Stevens and Robbins 2007) (see Sect. 1.4). This impediment was recognized as quickly as the theoretical concepts of using MAS were developed (Tanksley 1983; Helentjaris et al. 1985). In 1985, Helentjaris et al. demonstrated that DNA-based molecular markers in the form of restriction fragment length polymorphisms (RFLPs) could effectively identify differences between cultivated tomato and wild tomato species. Two years later, Nienhuis et al. (1987) demonstrated that MAS could identify quantitative trait loci (QTL) associated with insect resistance derived from Solanum habrochaites in an interspecific cross. The clear demonstration that polymorphic markers were relatively abundant between cultivated tomato and its wild relatives opened a new line of MAS utilizing DNA-based markers. Young et al. (1988) exploited the abundance of polymorphisms derived from linkage drag surrounding genes introgressed from S. peruvianum into tomato. They utilized near-isogenic lines (NIL) to identify two RFLP markers tightly linked to the Tm-2a viral resistance gene. Tomato’s importance as a crop and role as a model for genetics, fleshy fruit development, secondary metabolism, disease resistance, domestication, and evolution, has led to concerted efforts to develop genetic and genomic resources for this species. These efforts have rapidly advanced tomato genome mapping and MAS, and have culminated in the adoption of tomato as the model genome (see Sect. 1.6, 1.18) for the commercially important (e.g., potato, pepper, eggplant) Solanaceae family.