Miguel Leiva-Brondo

The role of traditional varieties of tomato as sources of functional compounds

BACKGROUND Traditional varieties of tomato, usually associated with excellent organoleptic quality, are increasingly appreciated in European quality markets. A collection of 126 populations of 16 traditional varieties from the east of Spain (a secondary diversity center for tomato) have been evaluated over 2 years in order to determine their potential value as sources of functional compounds, including ascorbic acid, lycopene, β-carotene and total phenolic content. RESULTS Population and population × year interaction significantly affected lycopene and ascorbic acid contents, while year effect was also significant for β-carotene. Despite finding some global trends in certain varieties concerning their functional value, high levels of variation have been found at the intra-varietal level. Populations with high levels of the compounds analysed have been found, as well as different levels of intra-population and inter-year variation. Maximum mean contents for both years have reached 308 mg kg(-1) ascorbic acid, 130 mg kg(-1) lycopene, 30 mg kg(-1) β-carotene and 89 mg caffeic acid 100 g(-1) total phenolic contents, though it is difficult to identify accessions with joint high values of the three compounds. CONCLUSION These results open the possibility to promote traditional materials as sources of functional compounds, thus strengthening their quality niches and consolidating their price premium. Additionally, these materials could also be used in breeding programs for quality.

Genetic Analyses Indicate Superiority of Performance of Cape Gooseberry (Physalis peruviana L.) Hybrids

ABSTRACT The use of hybrids as a new type of cape gooseberry (Physalis peruviana L.) cultivars could improve yield in this crop, but little or no information is available on hybrid perfomance. We studied several vegetative characters, yield, fruit weight and fruit shape, soluble solids content (SSC), titratable acidity (TA) and ascorbic acid content (AAC) in three hybrids of cape gooseberry and their parents grown outdoors and in a glasshouse. The highest yields were obtained with hybrids, specially in a glasshouse. Interaction dominance X environment for yield was very important; a higher dominance effect was detected in the glasshouse, than that observed outdoors. Quality characters were highly affected by the environment and showed variable results for the different families. For fruit composition traits, the additive and additive X environment interactions were most important. Broad-sense heritability for all characters was high to medium (0.48-0.91), indicating that a high response to selection would be expected. Hybrids can improve cape gooseberry yield without impairing fruit quality.

Influence of controlled deficit irrigation on tomato functional value

The effect of controlled deficit irrigation (CDI) on the accumulation of carotenoids, polyphenols and l-ascorbic acid was studied in conventional and high lycopene tomato cultivars. Plants were initially irrigated to cover 100%ETc and after the fruit set phase, the dose was reduced to 75% or 50% of ETc. CDI had no significant effect on the accumulation of carotenoids, while it increased the levels of the hydroxycinnamic acids chlorogenic and ferulic acids, the flavonoid rutin and l-ascorbic acid. Nevertheless, there were important interactions and this effect was highly dependent on the year and site of cultivation. Certain growing areas would be more favorable to supply high quality markets, and, fortunately, CDI would maximize polyphenol (100-75%ETc) and l-ascorbic acid (100-50%ETc) in these areas. A combination of the best genotype and growing area with CDI would offer high quality products, preserving a scarce resource: water.

New opportunities for developing tomato varieties with enhanced carotenoid content

The development of varieties with a high content of antioxidant compounds, such as carotenoids, has become a major focus in the marketing of tomato. Several mutants have been used in the development of high pigment varieties, but the significant influence of the environment on carotenoid content and the presence of negative side effects in vegetative growth and yield have limited the success of these variants. Consequently, the identification of alternative sources of variation in the quest for high carotenoid content is ongoing. In this study, 12 accessions of Solanum lycopersicum (including the former var cerasiforme) and S. pimpinelifolium have been evaluated in three different environments: open field and glasshouse cultivation at two sites. Three accessions (BGV6195 of S. pimpinellifolium, LA1423 of the former var cerasiforme and LA3633 a possible hybrid between S. pimpinellifolium and S. lycopersicum) showed outstanding and stable lycopene content, that doubled in all three environments the content of the positive control LA3538, with the high pigment-1 mutation (hp1). In addition, accession CATIE14812 would also be interesting as regards improvement of β-carotene content. These materials offer new opportunities in the development of tomato varieties with enriched and reliable carotenoid content and the close taxonomic relationship of these accessions with cultivated tomato will facilitate their use in breeding programs.

Sugar and acid profile of processing tomato cultivars grown under conventional or organic conditions

The optimization of tomato taste has gained importance during the last years following consumer demands of higher quality. At the same time consumers also demand a minimum impact on the environment during cultivation. The effect of conventional and organic cultivation on the sugar and acid profile of processing cultivars has been studied in the two main growing regions in Spain. Standard and high lycopene cultivars have been used in order to study the possibility of combining organoleptic and functional quality. High differences in the acid profile (malic vs. citric) and in the sugar accumulation of the cultivars were found. In some cases, the higher values in the content of taste-related compounds coincide with previously described high lycopene contents. The cultivation system had no significant effect on malic and citric acid accumulation, but it affected sugar accumulation and the sucrose equivalents (SEq) to citric and glutamic acid ratios. On average, 7.7 and 10.4% higher contents of glucose and fructose respectively were obtained with the organic cultivation system. The SEq to citric acid and SEq to glutamic acid ratios were consequently higher with this system (8.3 and 46.3% respectively). Organic cultivation of high lycopene cultivars might be an excellent selection to combine high organoleptic and functional quality targeted to quality markets.

Differences in Colour Development and Earliness Among Pepino Clones Sprayed with Ethephon

Most pepino (Solanum muricatum Aiton) clones have a long fruit ripening period. This hampers the introduction of this crop in intensive crop rotations [2]. Time elapsed between the fruit has reached its full size and ripeness can be extremely long, up to several months. Prohens et al. [3] have found that sprayings of 2-chloroethyl phosphonic acid (ethephon) can advance ripening of cv’ sweet Round’ between 1 and 3 weeks. However, several evidences suggest that there are differences amog different clones in the response to ethephon [4]. Here we study, in several clones, the differences induced by ethephon applications on fruit colour, which is the most common used maturity index for the pepino [1].