Growing conditions and seasonal fluctuations are critical factors affecting fruit and vegetable nutritional quality. The effects of two partially overlapping cropping seasons, early (ECS; January–May) and full (FCS; March–July), on the main carpometric traits and bioactive components of different watermelon fruits were investigated in the open field. Four watermelon genotypes, comprising of three commercial cultivars ‘Crimson Sweet’, ‘Dumara’, ‘Giza’, and the novel hybrid ‘P503 F1’, were compared. The carpometric traits varied significantly between genotypes. Soluble solids and yield were higher under FCS than ECS. The variation affecting colour indexes between the two growing seasons exhibited a genotype-dependent trend. The antioxidant components and radical scavenging activity of watermelon fruits were also significantly affected by differences in received solar energy and temperature fluctuations during the trial period. The average citrulline, total phenolics and flavonoid contents were 93%, 71% and 40% higher in FCS than in ECS. A genotype-dependent variation trend was also observed for lycopene and total vitamin C between cropping seasons. The hydrophilic and lipophilic radical scavenging activities of the pulp of ripe watermelon fruits of the different genotypes investigated varied between 243.16 and 425.31 µmol Trolox Equivalent (TE) of 100 g⁻¹ of fresh weight (fw) and from 232.71 to 341.67 µmol TE of 100 g⁻¹ fw in FCS and ECS, respectively. Our results, although preliminary, show that the functional quality of watermelon fruits is drastically altered depending on the environmental conditions that characterize the ECS and LCS.

Tomato landraces have progressively faded into obscurity, making way for new hybrids and elite tomato cultivars. This study presents a comprehensive evaluation of the agronomic attributes, physicochemical properties, and functional traits across seven cultivars, comprising two high-pigment varieties, ‘HLT−F81’ and ‘HLT−F82’, as well as five underutilized ancient-tomato genotypes considered as landraces. Most of the studied genotypes exhibited satisfactory horticultural and processing traits. The average fruit weight ranged from 73.3 g in ‘Rimone’ to 91.83 g in ‘HLT−F81’, while the soluble solids content ranged from 4.66 °Brix in ‘Justar’ to 6.08 °Brix in ‘HLT−F81’. The functional quality and the content of most antioxidants, as well as the antioxidant activity in both hydrophilic and lipophilic fractions, proved to be the most discriminating parameters among the tomato genotypes. The content of β−carotene and lycopene spanned from 2.94 mg kg⁻¹ fw in ‘Rio Grande’ to 13.94 mg kg⁻¹ fw in ‘HLT−F82’ and 227.8 mg kg⁻¹ fw in ‘HLT−F81’, yielding large variations compared to ‘Rio Grande’. The total phenolic content ranged from 139.83 mg GAE kg⁻¹ fw in ‘Rimone’ to 352.41 mg GAE kg⁻¹ fw in ‘HLT-F81’, while the flavonoid content varied from 136.16 mg RE kg⁻¹ fw in ‘Justar’ to 311.23 mg RE kg⁻¹ fw in ‘HLT-F82’. The presence of tocopherol isomers was genotype-dependent, with a higher content in lines carrying the high-pigment mutations. Among the tested tomato genotypes, the high-pigment tomato line ‘HLT−F81’ achieved the highest hydrophilic and lipophilic antioxidant activity values. This study primarily focused on the recovery and valorization of tomato genetic resources and landraces. It also aimed to identify desirable horticultural (yield, low-input, and low-water demand), processing (°Brix and titratable acidity), and quality (rich antioxidant berries) traits for introgression into new tomato cultivars better suited to the evolving climate conditions of the near future.

Landraces are considered a crucial component of biodiversity conservation, serving as a reservoir of genetic diversity. Consequently, the collection, cultivation, and detailed characterization of such landraces constitute an inherent aspect of the world’s natural resource heritage. This effort holds promise for the development of elite varieties capable of thriving amidst continuous global climate fluctuations. In this context, we conducted a comprehensive assessment of the main agronomic attributes, physico-chemical properties, and functional quality traits of the major hot pepper landraces adapted to diverse climatic conditions in Tunisia. These landraces include ‘Dhirat’, ‘Semmane’, ‘Beldi’, ‘Nabeul’, ‘Jerid’, ‘Mahdia’, ‘Cayenne’, ‘Kairouan’, and ‘Baklouti’. Most of the pepper landraces exhibited satisfactory yields, ranging from 1163.25 to 1841.67 g plant⁻¹ in ‘Jerid’ and ‘Kairouan’, respectively, indicating robust productivity, especially under prevailing climatic changes and high temperatures during both growing cycles. The levels of antioxidants comprising capsaicinoids, carotenoids, phenolics, and tocopherols, as well as radical scavenging activity, emerged as key discriminating factors among pungent pepper landraces. Irrespective of genotype, capsaicin and dihydrocapsaicin constituted the major capsaicinoids, accounting for 44–91% of the total capsaicinoids content. Total capsaicinoids ranged from 1.81 µg g⁻¹ fw to 193.71 µg g⁻¹ fw, with ‘Baklouti’ and ‘Jerid’ identified as the most pungent landraces. Total carotenoids ranged from 45.94 µg g⁻¹ fw to 174.52 µg g⁻¹ fw, with ‘Semmane’ and ‘Jerid’ exhibiting the highest levels. Considerable variation was observed in β-carotene content, spanning from 3% to 24% of the total carotenoids. α-Tocopherol content ranged from 19.03 µg g⁻¹ fw in ‘Kairouan’ to 30.93 µg g⁻¹ fw in ‘Beldi’, exerting a notable influence on the overall tocopherol content. Conversely, the β- and γ-tocopherol isomers were detected at very low concentrations. The total vitamin C content ranged from 132 mg 100g⁻¹ fw in ‘Mahdia’ to 200 mg 100 g⁻¹ fw in ‘Nabeul’, indicating relatively low genetic variability. However, large variability was detected in total phenolics content, ranging from 168.58 mg GAE kg⁻¹ fw in ‘Beldi’ to 302.98 mg GAE kg⁻¹ fw in ‘Cayenne’. Landraces such as ‘Dhirat’, ‘Nabeul’, ‘Semmane’, ‘Kairouan’, ‘Cayenne’, and ‘Mahdia’ appear suitable for both fresh consumption and processing, owing to their favorable average fruit weight, soluble solids content, and bioactive content. Among the pepper landraces tested, ‘Cayenne’ achieved the highest value of radical scavenging activity in both hydrophilic and lipophilic fractions (RSAHF and RSALF), with variations ranging from 59% to 120% for RSAHF and from 4% to 63% for RSALF. This study aims to preserve and enhance the value of local genetic resources and contribute to identify desirable traits for incorporation into breeding programs to develop high-quality, high-yielding landraces and elite lines.

Landraces are considered a crucial component of biodiversity conservation, serving as a reservoir of genetic diversity. Consequently, the collection, cultivation and detailed characterization of such landraces constitute an inherent aspect of the world’s natural resource heritage. This effort holds promise for the development of elite varieties capable of thriving amidst continuous global climate fluctuations. In this context, we conducted a comprehensive assessment of the main agronomic attributes, physico-chemical properties, and functional quality traits of the major hot pepper landraces adapted to diverse climatic conditions in Tunisia. These landraces include ‘Dhirat’, ‘Semmane’, ‘Beldi’, ‘Nabeul’, ‘Jerid’, ‘Mahdia’, ‘Cayenne’, ‘Kairouan’ and ‘Baklouti’. Most of the pepper landraces exhibited satisfactory yields, ranging from 1163.25 to 1841.67 g plant-1 in ‘Jerid’ and ‘Kairouan’, respectively, indicating robust productivity, especially under prevailing climatic changes and high temperatures. Landraces such as ‘Baklouti’, ‘Beldi’, ‘Nabeul’, ‘Semmane’, ‘Kairouan’ and ‘Mahdia’ appear suitable for both fresh consumption and processing, owing to their favorable average fruit weight and soluble solids content. Functional quality and the levels of antioxidants, as well as radical scavenging activity, emerged as key discriminating factors among pepper landraces. Irrespective of genotype, capsaicin and dihydrocapsaicin constituted the major capsaicinoids, accounting for at least 87% of the total. Total capsaicinoids ranged from 1.81 µg g−1 to 193.71 µg g−1, with ‘Baklouti’ and ‘Jerid’ identified as the most pungent landraces. Total carotenoids ranged from 45.94 µg g−1 to 174.52 µg g−1 with ‘Semmane and ‘Jerid’ exhibiting the highest levels. Considerable variation was observed in β-carotene content, spanning from 3% to 24% of the total carotenoids. α-Tocopherol content ranged from 19.03 µg g-1 fw in ‘Kair-ouan’ to 30.93 µg g-1 fw in ‘Beldi’, exerting a notable influence on the overall tocopherol content. Conversely, the other isomers were detected at very low concentrations. The total vitamin C content ranged from 132 mg 100g-1 fw in ‘Mahdia’ to 200 mg 100 g-1 fw in ‘Nabeul’, indicating relatively low genetic variability. However, large variability was detected in total phenolics content, ranging from 168.58 mg GAE kg-1 fw in ‘Beldi ‘to 302.98 mg GAE kg-1 fw in ‘Cayenne’. Among the pepper landraces tested, ‘Cayenne’ achieved the highest value of radical scavenging activity in both hydrophilic and lipophilic fractions (RSAHF and RSALF), with variations rang-ing from 59% to 120% for RSAHF and from 4% to 64% for RSALF. This study aims to: 1) preserve and enhance the value of local genetic resources, 2) identify desiderable traits for incorporation into breeding programs, and 3) develop high-quality, high-yielding cultivars capable of with-standing climate variations.