The characterization of Lycopersicon germplasm for internal quality properties is essential to choose suitable donor parents for breeding programs. When donor parents belong to species of subgenus Eulycopersicon, which are phyletically closer to L. esculentum Mill., the recovery of agronomic traits is faster. When using these materials, a careful selection of donor parents which could improve several internal quality properties allows the acceleration of these breeding programs. In this work, we combine general determinations, such as soluble solid content, titratable acidity, pH, total sugars, pectic substances and total protein contents with precise high-performance liquid chromatography (HPLC), quantitations of individual compounds (vitamin C; citric, malic, fumaric and oxalic acids; glucose, fructose, and sucrose), in order to obtain a more complete characterization of flavor intensity and nutritional properties in Lycopersicon germplasm. The multidimensional analysis of all these variables allows classification of several accessions of L. esculentum Mill. and L. pimpinellifolium (Jusl.) Mill., according to their usefulness for internal quality breeding programs of fresh tomato. The classification obtained and the comparison of accessions quality characteristics with selected controls show that five of the L. pimpinellifolium (Jusl.) Mill. accessions tested can be of great usefulness for being used in breeding for internal quality characteristics. A flavor intensity ≈625% higher than commercial hybrids was obtained in the best accession tested. Some of these L. pimpinellifolium (Jusl.) Mill. accessions showed better flavor intensity properties than a high SSC L. cheesmanii Riley control, traditionally used in internal quality breeding. In addition, three of the L. esculentum Mill. accessions tested with medium-to-high flavor intensity value could be useful in advanced stages of breeding programs.

A capillary zone electrophoresis (CZE) procedure for the simultaneous determination of the major organic acids (oxalate, malate and citrate) and carbohydrates (fructose, glucose and sucrose) in Lycopersicon fruits is reported. Comparison of this method with routine HPLC methods indicates that the CZE method offers several attractive features (speed, resolution, sensitivity and cost) which significantly improve the determination of these compounds. Detection limits were better than 1.6 mg ml À1 for organic acids and from 13 to 24 mg ml À1 for carbohydrates; repeatabilities were better than 2.1% for migration times and between 1.4 and 7.3% for peak areas. The proposed protocol is very useful to characterise large series of tomato samples not only in breeding programmes but also in systematic and routine analysis in the tomato industry.

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The genetic potential of accessions from Solanum section Lycopersicon (S. lycopersicum L., S. lycopersicum var. cerasiforme, S pimpinellifolium L., and S. habrochaites Knaap & Spooner) for breeding tomato taste has been studied in three environments with clonal replicates. The environment clearly affected the accumulation and level of variation of sugars and acids and derived variables through a direct effect. It seems that photosynthetically active radiation would exert a major effect on sugar accumulation while in the case of organic acids the effect of temperature might be more important. Even more, important genotype × environment interactions can considerably modify the real value of germplasm, being considerably higher in wild species. The environment affected not only mean contents but also the levels of variation. Thus, the need to develop multienvironmental screening programs is suggested to identify solid sources of variation. An important intraaccession variability was also found in wild germplasm, emphasizing the need to analyze a high number of plants per accession in order to identify sources of variation. Accessions with a significant genotypic contribution to the accumulation of sucrose within the Lycopersicon group were identified and may be interesting to analyze the regulation of vacuolar invertase. Accessions with different genotypic contributions to citric, malic, and glutamic acid accumulation have also been identified. These accessions will be valuable for the development of breeding programs considering the acid component of taste. Additionally, these genetic resources will be interesting to study the regulation of the tricarboxylic acid cycle and the gamma-aminobutyric acid shunt.

Tomato breeders have hitherto selected for yield, uniformity and disease resistance rather than for internal qualities such as taste that depend on appropriate amounts and proportions of many different constituents. In order to improve internal quality it is necessary to find balanced donor parents with high contents of these individual constituents in order to develop this strategy. A methodology to evaluate all constituents together is also necessary. This work characterizes and classifies accessions of Lycopersicon to assist the selection of parents for several internal qualities. Thirty-eight accessions of L. esculentum, L. pimpinellifolium, L. hirsutum, L. pennellii and L. peruvianum have been studied, and their taste and vitamin C content characteristics have been measured. Some of the variables studied are complex since many chemical constituents are involved (pH,°Brix (SSC), titratable acidity), whereas other variables are individual constituents (vitamin C, oxalic acid, malic acid, citric acid, fructose, glucose and sucrose). Therefore, individual taste components in Lycopersicon accessions have been analysed by using precise analytical techniques (capillary zone electrophoresis) and statistical methods (principal component, cluster and GGE biplot analyses) for comparisons to be made not only among these, but also among controls (four breeding lines and one commercial hybrid). All analyses performed have allowed both for a good classification and for a selection of materials to be made. Two L. pimpinellifolium accessions are very interesting to use as donor parents in the first steps of tomato taste breeding programmes, since they are balanced and have shown three times the taste intensity of controls. Furthermore, characterization by individual constituents (citric, malic, oxalic and ascorbic acids, glucose, fructose, sucrose, etc.) has been found to be a precise tool to classify and select Lycopersicon germplasm for internal quality attributes.