BACKGROUND: The agricultural production system and cultivation practices are critical factors in determining yield and food nutritional quality. Controversy remains regarding whether or not organic foods have a nutritional advantage when compared with their conventionally produced counterparts. In this study the effect of conventional and organic production systems on yield, physicochemical and nutritional properties of four field tomato cultivars (Perfectpeel, Rio Grande, Hypeel 108 and Firenze) was determined. In the organic system, different fertiliser combination treatments were used.

This study investigates the antioxidant components [lycopene, total phenolics, total flavonoids, ascorbic acid (AsA) and dehydroascorbic acid (DHA)] as well as antioxidant activities of the hydrophilic and lipophilic fractions (AAHF and AALF) of peel, pulp and seed fractions isolated from red-ripe berries of the ordinary tomato cultivar Rio Grande and the two high-lycopene tomato breeding lines HLT-F61 and HLT-F62 simultaneously grown in an open-field of Northern Tunisia. Significant differences (p < 0.05) were found among cultivars for each trait studied. All fractions isolated from the red-ripe berries of HLT lines showed higher lycopene, total phenolics and total flavonoid contents, as well as higher AAHF and AALF, than those isolated from Rio Grande. Regardless of the fraction, HLT-F61 had the highest lycopene content (893.0 mg per kg fw, 280.0 mg per kg fw, and 47.5 mg per kg fw in peel, pulp and seed fractions, respectively) and total phenolics at least 2-fold and 3-fold higher than HLT-F62 and Rio Grande, respectively. Peel and seed fractions from HLT-F61 red-ripe tomato berries had the highest AsA content (345 mg per kg fw and 115 mg per kg fw, respectively), while no significant difference was found in the seed fraction between HLT-F62 and Rio Grande. The HLT-F62 pulp fraction showed the highest content of AsA (186 mg per kg fw) and DHA (151 mg per kg fw) among all the assayed cultivars. Except for the peel fraction, where HLT-F61 had similar AAHF values to HLT-F62, the high-lycopene line HLT-F61 showed higher AAHF values than HLT-F62 and Rio Grande. Regardless of the fraction, the highest AALF values were recorded in HLT-F61 berries. Thus, both HLT tomato lines are promising for the introduction, as advanced hybrids, in either fresh market or processing industry.

The antifungal activity of chitosan against Fusarium spp. was investigated based on in vitro and in vivo assays, and its possible modes of action were also explored. Chitosan applied at 4.0 g/L of acetic acid‐distilled water solution significantly decreased the mycelial growth of Fusarium oxysporum, Fusarium sambucinum and Fusarium graminearum by 88.4%, 89.0% and 89.8%, respectively. Tuber treatment by chitosan (4.0 g/L) of acetic acid‐distilled water solution, prior to inoculation, reduced dry rot severity induced by F. oxysporum and F. sambucinum by 60.0% and 48.2%, respectively. When tested as plant treatment, potato plants inoculated with Fusarium species, exhibited 33.5%–45.3% less wilting severity as compared to the control. This abiotic treatment improved the phenolic compounds activities and defence‐related enzymes such as peroxidase and polyphenoloxidase in potato tubers inoculated with Fusarium spp. Results clearly demonstrated that chitosan could be explored as an alternative agent to chemical fungicides for the control of tuber dry rot and Fusarium wilt through induction of the plant defence system.

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Organic tomato cultivation is growing all over the world due to its healthy functional properties and environmental concerns. Recently, some new varieties with increased functional properties, particularly high lycopene, have been developed. However, few were assessed under organic farming systems. The objective of this study was to evaluate physico-chemical properties and the main bioactive compound contents, as well as lipophilic, hydrophilic and total radical scavenging activities of a recently developed high lycopene tomato variety homozygous for hp-2dg genes (HLT-F71) grown under organic conditions for two non-consecutive years (2019 and 2021) compared to the ordinary control ‘Nemador’ variety. The lycopene, β-carotene, total phenol, flavonoid, vitamin C, radical scavenging activity and tocopherols were analyzed by using spectrophotometric and HPLC methods, respectively. The high lycopene content variety presented suitable marketable yield, average fruit weight, pH, titratable acidity, firmness and higher °Brix, pulp color than the control. Additionally, it has significantly higher lycopene, β-carotene, total phenol, flavonoid, vitamin C and particularly considerable α-tocopherol contents, as well as radical scavenging activity. The high lycopene tomato variety with hp genes proved to be an effective sustainable variety for enhancing tomato fruit yield and functional properties even under organic grown conditions.

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