Climate change poses a significant threat to agricultural productivity, particularly in low-input systems where resilient cultivars are crucial. Traditional pepper (Capsicum annuum L.) landraces represent a valuable genetic reservoir for adaptation, yet their agronomic and nutritional potential remains underexplored. In this study, twenty-five Greek pepper landraces and commercial varieties were comprehensively evaluated for morphological traits, early and total yield characteristics, and key fruit quality parameters. The results revealed substantial phenotypic diversity in both vegetative and reproductive traits, as well as considerable variation in fruit nutritional composition across the tested genotypes. Notably, ‘Skopos’, ‘Mesoropi’, and ‘Lygaria’ demonstrated superior yield performance, while ‘Pogoniou’, ‘Lyra’, and ‘Kantanou’ excelled in several nutritional quality traits, including high phenolic content, vitamin C, and antioxidant capacity. Heatmap analysis further identified ‘Pogoniou’, ‘Filuria’, ‘Lyra’, ‘Lagada’, and ‘Lygaria’ as consistently ranking among the top performers across yield and quality traits. These findings highlight the dual agronomic and nutritional value of traditional pepper landraces, underscoring their importance as a genetic resource for breeding programs. Overall, the study highlights the importance of conserving and utilizing local pepper germplasm as a sustainable approach to improve productivity, nutritional quality, and resilience in the face of climate change and low-input cultivation systems.

The agricultural industry faces increasing environmental degradation due to the intensive use of conventional chemical fertilizers, leading to water pollution and alterations in soil composition. In addition, root-knot and cyst nematodes are major constraints to cucumber production, causing severe root damage and yield losses worldwide, underscoring the need for sustainable alternatives to conventional fertilization and pest management. Under greenhouse conditions, a four-month cultivation trial evaluated vegetable oil-, micronutrient-, and activated flavonoid-based biostimulants, applying Key Eco Oil^® (Miami, USA) via soil drench (every 15 days) combined with foliar sprays of CropBioLife^® (Victoria, Australia) and KeyPlex 120^® (Miami, USA) (every 7 days). Results showed reduced parasitic nematodes by 66% in soil and decreased gall formation by 41% in roots. Chlorophyll fluorescence and infrared gas analysis revealed higher oxygen-evolving complex efficiency (38%), increased PSII electron transport, improved the fluorescence decrease ratio, also known as the vitality index (Rfd), and higher CO₂ assimilation compared to conventional treatments. Processed cucumbers showed higher sugar and nearly double ascorbic acid content, with improved flesh consistency and color. Therefore, the application of these bioactive products significantly reduced nematode infestation while enhancing plant growth and physiological performance, underscoring their potential as sustainable tools for crop cultivation and protection. These results provide evidence that sustainable bioactive biostimulants improve plant resilience, productivity, and nutritional quality, offering also an environmentally sound approach to pest management.

Plant biostimulants may alter photosynthetic energy use and leaf structure, but their effects on complementary PSII energy partitioning in both cucumber leaves and fruits remain insufficiently characterized. Using plant material from a commercial greenhouse trial previously reported for agronomic outcomes, we evaluated a combined CropBioLife^®, KeyPlex 120^®, and Key Eco Oil^® application protocol relative to conventional management. Chlorophyll Content Index (CCI), chlorophyll fluorescence imaging, and leaf anatomical traits were assessed. Under low light (LL; 455 μmol photons m⁻² s⁻¹), the combined-treatment greenhouse showed higher ΦPSII than the conventional-control greenhouse by 22% in fruits and 50% in leaves; fruit ΦNPQ was 17% higher, whereas ΦNO was 12% lower in fruits and 26% lower in leaves. Under high light (HL; 973 μmol photons m⁻² s⁻¹), differences in ΦPSII were smaller, while leaf ΦNO remained 17% lower. CCI was 38% higher in fruits and 52% higher in leaves. In leaves, spongy parenchyma thickness increased from 110 ± 3.4 to 135 ± 4.1 μm, palisade parenchyma thickness from 75 ± 2.1 to 78 ± 1.8 μm, total leaf thickness from 230 ± 4.6 to 245 ± 5.2 μm, and intercellular air-space area from 420 ± 18 to 610 ± 22 μm². The parallel physiological and anatomical differences are consistent with a possible functional association, but gas exchange, mesophyll conductance, ROS, and water-use efficiency were not measured in the present dataset. Because the two management regimes occupied separate, non-replicated greenhouses and received different crop-protection inputs, the findings should be interpreted as treatment-associated differences rather than causal effects attributable to individual products.