Agronomic Performance and Nutraceutical Quality of a Tomato Germplasm Line Selected under Organic Production System

Organic tomato production is increasing worldwide, thus making necessary the development of varieties adapted to this farming system. It is now well known that the implementation of local tomato plant breeding programs for organic farming is required to increase the performance of varieties in this typology of cultivation regime. In this research, the agronomic performance, nutraceutical contents, and radical scavenging activity of a tomato germplasm line (OSTGL), selected under organically grown conditions, were evaluated for two consecutive years (2018 and 2019) in comparison with the variety ‘Rio Grande’, frequently grown organically in Tunisia. Carotenoids, phenolics, vitamin C, and radical scavenging capacity were assayed spectrophotometrically, while tocopherols were analyzed by HPLC. All data were not affected by year-to-year variability. The OSTGL line showed significantly higher marketable yield, total phenol, flavonoid, vitamin C, α-tocopherol and γ-tocopherol contents, along with radical scavenging activity. The OSTGL red-ripe berries also showed comparable values for average weight, soluble solids, pH, titratable acidity, firmness and coloration, as well as lycopene and β-carotene contents. This open pollinated tomato germplasm line demonstrated to be an effective sustainable variety for improving fruit yield, agronomic, and nutraceutical characteristics under an organic management system

Bioactive compounds and antioxidant activities of different watermelon (Citrullus lanatus (Thunb.) Mansfeld) cultivars as affected by fruit sampling area

This investigation reports the variability of antioxidant components and antioxidant activities of six watermelon cultivars (cvs) (four commercial cvs Aramis, Crimson Sweet, Dumara, Giza, and two new selections P503 and P403 produced by the National Agricultural Research Institute of Tunisia) as influenced by sampling area. All cvs were simultaneously grown in an open-field and subjected to identical horticultural practices in order to minimize the effects of environmental conditions and maximize those related to genotype. Significant differences were found between watermelon cvs for lycopene, phenolics, flavonoids, ascorbic acid (AsA), dehydroascorbic acid (DHA) and total vitamin C (AsA + DHA) contents, as well as in the antioxidant activity of their hydrophilic and lipophilic fractions. P503 cv showed the highest lycopene and flavonoid contents. Crimson Sweet and Giza cvs showed the highest HAA and LAA when TEAC was used as assay method, while the highest HAA and LAA were detected in Giza and Dumara cvs and in P503 cv, respectively, when FRAP assay was used. This study demonstrates that the amount of each specific antioxidant, as well as the HAA and LAA, were both influenced by genotype and sampling area, emphasizing the need to evaluate watermelon biodiversity in order to improve its nutritional value