Search Results (17)

Fruit color serves as a crucial visual indicator in chili peppers and is closely linked to the bioactive components that determine their economic and nutritional value. However, the specific components and potential molecular mechanisms that impact fruits’ development and color changes are less thoroughly understood. Here, we utilized three chili pepper varieties (CS03, CS29, and L816) at different developmental stages (young fruit stage, turning color stage, and mature stage) as research materials and integrated transcriptome and non-targeted metabolome analyses to explore the variation in bioactive components and color to explain the molecular regulatory mechanisms underlying different colors of chili peppers during the young fruit stage. Our results showed that flavonoids were the most enriched differential metabolites; aromadendrin 4′-glucoside, diospyrin, precarthamin, kaempferol-3-O-rutinoside, and kaempferol-3-O-Glucoside were significantly enriched in the young fruit stage of pepper CS03; and cyanidin, delphinidin, and cyanidin 3-glucoside were major contributors to the color formation. The upregulation of anthocyanin was related to the structural genes CaC4H, Ca4CL, CaCHS, CaF3H, CaANS, and CaUFGT, and key transcription factors such as CaMYBs and CabHLHs may have contributed to the differential accumulation of anthocyanins in CS03; in addition, RT-qPCR validation was correlated with anthocyanins, but also with flavonoids. This article mainly focuses on the changes in chili pigments, particularly anthocyanins, and explores the molecular mechanisms involved. This provides a reference for research on color in solanaceae vegetables and lays a theoretical foundation for further research on the bioactive components of chili peppers, as well as for optimizing harvesting practices and dietary recommendations. Full article

Chili pepper (Capsicum annuum L.), a globally important economic crop, faces production challenges characterized by high labor intensity, cost, and inefficiency. Intelligent technologies offer key opportunities for sector transformation. This review begins by outlining the diversity of major chili pepper cultivars, differences in key quality indicators, and the resulting specific harvesting needs. It then reviews recent progress in intelligent perception, recognition, and automation within the chili pepper industry. For perception and recognition, the review covers the evolution from traditional image processing to deep learning-based methods (e.g., YOLO and Mask R-CNN achieving a mAP > 90% in specific studies) for pepper detection, segmentation, and fine-grained cultivar identification, analyzing the performance and optimization in complex environments. In terms of automation, we systematically discuss the principles and feasibility of different mechanized harvesting machines, consider the potential of vision-based keypoint detection for the point localization of picking, and explore motion planning and control for harvesting robots (e.g., robotic systems incorporating diverse end-effectors like soft grippers or cutting mechanisms and motion planning algorithms such as RRT) as well as seed cleaning/separation techniques and simulations (e.g., CFD and DEM) for equipment optimization. The main current research challenges are listed including the environmental adaptability/robustness, efficiency/real-time performance, multi-cultivar adaptability/flexibility, system integration, and cost-effectiveness. Finally, future directions are given (e.g., multimodal sensor fusion, lightweight models, and edge computing applications) in the hope of guiding the intelligent growth of the chili pepper industry. Full article

Mechanized chili harvesting is essential for improving efficiency, reducing costs, and alleviating labor intensity in production. However, issues such as low harvesting efficiency, high rates of breakage, and contamination continue to severely hinder the development of mechanized chili harvesting. This study provides an overview of global chili production regions and varieties, examining three harvesting approaches: single-pass, multi-stage, and multi-pass approaches. It describes the operational principles of key harvesting mechanisms, including the helical spiral-type, drum finger-type, long-rod comb-type, and belt-mounted comb finger-type mechanisms, and summarizes research progress in major producing countries, such as the United States and China. The paper evaluates both airflow-based and mechanical cleaning–separation devices, highlighting the combined airflow mechanical systems as the most promising approach and reviews their current development status. It also addresses structural challenges in chassis, frameworks, and conveyance systems. Finally, the paper analyzes solutions to the existing challenges, emphasizing the integration of intelligent technologies to resolve mechanical issues, and outlines the future prospects of intelligent development in mechanized chili harvesting. Full article

To address issues such as leaf occlusion, misalignment of the harvesting robotic arm, and limited harvesting range in hillside chili fields, this paper designs an intelligent harvesting system based on 3D point cloud reconstruction and multi-mechanism collaborative leveling. The system integrates real-time data from a LiDAR and IMU inertial navigation system to reconstruct the chili point cloud occluded by leaves from multiple perspectives. To address issues such as misalignment of the robotic arm caused by terrain undulations, the system integrates an adaptive leveling platform and an H-shaped planar slide, combined with a gyroscope to dynamically adjust the arm’s posture in real time, ensuring arm stability while expanding its workspace. In addition, to ensure harvesting efficiency and pepper integrity, an integrated cutting–gripping flexible end effector is designed to achieve synchronized cutting and collection operations. The experiment shows that the system achieves recognition accuracy of 81.95% for occluded chili peppers and 89.04% for non-occluded chili peppers. The harvesting success rate is 86.33%, with a single harvesting operation taking 13.17 s. During prolonged operation, the harvesting success rate can be maintained at approximately 85.1%. In summary, the intelligent harvesting system based on 3D point cloud reconstruction and multi-mechanism collaborative leveling provides a feasible solution for automated pepper harvesting. Full article

Chili pepper, a widely cultivated and consumed crop, faces challenges in accurately determining maturity due to issues such as occlusion, small target size, and similarity between fruit color and background. This study presents an enhanced YOLOv8n-based object detection model, YOLO-ALW, designed to address these challenges. The model introduces the AKConv (Alterable Kernel Convolution) module in the head section, which adaptively adjusts the convolution kernel shape and size based on the target and scene, improving detection performance under occlusion and dense environments. In the backbone, the SPPF_LSKA (Spatial Pyramid Pooling Fast-Large Separable Kernel Attention) module enhances the integration of multi-scale features, facilitating accurate differentiation of peppers at various maturity stages while maintaining low computational complexity. Additionally, the Wise-IoU (Wise Intersection over Union) loss function optimizes bounding box learning, further improving the detection of peppers in occluded or background-similar scenarios. Experimental results demonstrate that YOLO-ALW achieves a mean average precision (mAP_0.5) of 99.1%, with precision and recall rates of 98.3% and 97.8%, respectively, outperforming the original YOLOv8n by 3.4%, 5.1%, and 9.0%, respectively. Grad-CAM feature visualization highlights the model’s improved focus on key fruit features. YOLO-ALW shows significant promise for high-precision chili pepper detection and maturity recognition, offering valuable support for automated harvesting applications. Full article

Chili peppers are globally cultivated for their rich bioactive compound profile. This study investigates the impact of two biostimulants, Humix^® and Energen, on Capsicum chinense ‘Habanero Orange’ and Capsicum annuum ‘Kristian’, focusing on quantitative and qualitative parameters. Conducted over two years with three annual harvests, the research assesses the effects of biostimulant application on yield, fresh fruit number, fruit weight, drying ratio, capsaicin, dihydrocapsaicin, and ascorbic acid content (via HPLC-DAD analysis), as well as carotenoid levels (via spectrophotometric analysis). Biostimulant application significantly increased (p ≤ 0.05) total yields and capsaicin levels. Harvest timing also influenced dihydrocapsaicin and capsaicin levels, with the third harvest showing the highest values (p ≤ 0.001). The effects on ascorbic acid and carotenoids were variable and depended on genotype, harvest, and treatment. Thus, our study provides insights into the dynamic responses of Capsicum species to biostimulants under variable climatic conditions, contributing new knowledge to agricultural practices and the scientific understanding of biostimulant effects in Capsicum production. Full article

In response to the low accuracy and slow detection speed of chili recognition in natural environments, this study proposes a chili pepper object detection method based on the improved YOLOv8n. Evaluations were conducted among YOLOv5n, YOLOv6n, YOLOv7-tiny, YOLOv8n, YOLOv9, and YOLOv10 to select the optimal model. YOLOv8n was chosen as the baseline and improved as follows: (1) Replacing the YOLOv8 backbone with the improved HGNetV2 model to reduce floating-point operations and computational load during convolution. (2) Integrating the SEAM (spatially enhanced attention module) into the YOLOv8 detection head to enhance feature extraction capability under chili fruit occlusion. (3) Optimizing feature fusion using the dilated reparam block module in certain C2f (CSP bottleneck with two convolutions). (4) Substituting the traditional upsample operator with the CARAFE(content-aware reassembly of features) upsampling operator to further enhance network feature fusion capability and improve detection performance. On a custom-built chili dataset, the F_0.5-score, mAP_0.5, and mAP_0.5:0.95 metrics improved by 1.98, 2, and 5.2 percentage points, respectively, over the original model, achieving 96.47%, 96.3%, and 79.4%. The improved model reduced parameter count and GFLOPs by 29.5% and 28.4% respectively, with a final model size of 4.6 MB. Thus, this method effectively enhances chili target detection, providing a technical foundation for intelligent chili harvesting processes. Full article

China’s Guizhou is a typical karst landscape province with high production of chili pepper, but it is mostly planted in mountainous areas, while manual harvesting of chili pepper has the deficiencies of high labor intensity, low efficiency, and high labor cost; in addition, there is no harvesting machinery applicable to the dense planting pattern of the chili pepper in mountainous areas in China. The fully hydraulic mountain track-based self-propelled pepper harvester 4JZ-1.0A is designed to solve the above problems. The pepper harvester spiral comb picking head is an important part of the whole machine design, the design of the hydraulic system of the working circuit of the picking head is the key to realizing the hydraulic control part of the whole system. In this paper, the working principle diagram of the improved load-sensitive hydraulic system is designed and analyzed for the study of whether the working circuit of the pepper picking head of the pepper machine can meet the requirements of mountain operation, taking the working circuit of the mountain pepper harvester as the research object. In addition, the load-sensitive pump model and the simulation model of the whole working circuit are established by the AMESim platform 2019.2 (Siemens simcenter amesim). The operating performance of the system under variable flow conditions, variable load conditions, and an improved sensitive system is analyzed. The simulation results show that the improved load-sensitive system can effectively reduce the oscillation and cavitation during cylinder operation and improve the system efficiency and the performance and service life of the components. The performance of the hydraulic system of the working circuit of the mountain pepper harvester was verified in the test, meeting the requirements of working use. This provides a theoretical basis for the improvement and optimal design of a mountain pepper harvester hydraulic system. Full article

The commercial and nutritional quality of chili peppers deteriorates rapidly after harvest. So far, little is known about the effect of temperature on postharvest chili pepper quality. This study elucidated the effects of two temperatures (20 °C and 30 °C) on chili peppers’ postharvest firmness, flavor, and nutritional attributes. We found that compared to 20 °C, 30 °C escalated the decline in fruit firmness, capsaicin content, and dihydrocapsaicin content, while enhancing the increment in water loss and electrical conductivity, as well as total carotenoids and ascorbic acid content. The contents of most amino acids (AAs) decreased significantly during postharvest storage compared to their initial values, whether stored at 20 °C or 30 °C; however, 30 °C had a more substantial impact than 20 °C. Meanwhile, as for soluble protein and amino acid compositions, the effect of storage temperature was genotype-dependent, as reflected by differential changes in total AA contents, single AA contents, essential AA ratio, delicious AA ratio, etc., under the 20 °C or 30 °C treatments. In conclusion, our findings reveal the influence of temperature on pepper quality, showing that the storage temperature of 20 °C was better for maintaining chili quality than 30 °C from the perspective of overall commercial attributes. Full article

Chili pepper is an important vegetable and spice crop with high post-harvest deteriorations in terms of commercial and nutritional quality. Light-emitting diodes (LEDs) are eco-friendly light sources with various light spectra that have been demonstrated to improve the shelf-life of various vegetables by manipulating light quality; however, little is known about their effects on the post-harvest nutritional quality of chili peppers. This study investigated the effects of different LED lightings on the post-harvest firmness and nutritional quality of chili peppers. We found that red and blue light could increase the content of capsaicinoids, whereas white and red light could increase the essential and aromatic amino acid (AA) content in pepper. Nonetheless, the influence of light treatments on AA contents and compositions depends strongly on the pepper genotype, which was reflected by total AA content, single AA content, essential AA ratio, delicious AA ratio, etc., that change under different light treatments. Additionally, light affected fruit firmness and the content of nutrients such as chlorophyll, vitamin C, and total carotenoids, to varying degrees, depending on pepper genotypes. Thus, our findings indicate that LED-light irradiation is an efficient and promising strategy for preserving or improving the post-harvest commercial and nutritional quality of pepper fruit. Full article

The winnowing machine of chili pepper harvesters was developed to reduce the potential problem of low pepper stem and fruit separation. The developed winnowing machine was combined with two impellers and a center bearing to prevent a strain on the drive shaft and to ensure durability. The terminal velocity of chili pepper was measured, and an aerodynamic analysis was conducted based on this winnowing machine. A CFD (Computational Fluid Dynamics, Ansys Fluent 2020 R1) analysis was conducted for three levels of discharge port guide form (0, 3, and 5 guides) and three levels of rotating speed (1600, 1800, and 2000 RPM) of a winnowing machine designed utilizing aerodynamic analysis results. A validation test was conducted by fabricating a winnower test device. As for aerodynamic analysis conducted using measured values of terminal velocity, chili pepper fruits were collected at an outlet wind speed lower than 17.5 m/s and chili pepper branches were separated at a speed higher than 12.5 m/s. As a result of CFD analysis, the wind speed deviation at outlets of the 0-, 3-, and 5-guide depending on the rotating speed appeared to be 15.8, 1.4, and 1.0 m/s on average, respectively. The result of the CFD analysis showed values higher than wind speeds of the actual winnower test device by a minimum of 0 and a maximum of 2.4 m/s. Through the CFD analysis and the wind speed validation test of the winnower test device, optimal conditions to separate foreign materials were found to be a winnowing machine at a rotating speed of 1800 RPM with a discharge port having three guides or a winnowing machine at a rotating speed of 2000 RPM with a discharge port having five guides. Full article

The chili pepper harvester has shown potential problems of low pepper stem separation and a high pepper damage rate. The low pepper stem separation has required additional labor, which consists of separating the pepper and stem after pepper harvesting. To improve the stem separation and sorting function of pepper harvesters, three-shaft and four-shaft drum-type stem-separation devices were manufactured, and performance tests were conducted to assess these devices. In an attempt to reduce the damage rate, a brush was used as the teeth in the drum-type stem-separation device. In the factor test, the rotational speeds of shaft 1(A), shaft 2(B), shaft 3(C), and the conveyor for the three-shaft drum were 0.9, 2.7, 1.3, and 0.5 m/s, respectively. The rotational speed of the four-shaft drum was the same as that of the three-shaft drum except for shaft 4(D), and the rotational speed of this additional D was set to 1.3 m/s, which was the same as that of C. In the non-moving status during the non-picking operation of the pepper harvester, the average stem-separation efficiency (SSE) of the four-shaft drum increased by 1.2%, the average pepper with twig rate (PTR) decreased by 5.9%, and the average damage rate (DR) increased by 3.7% compared to the three-shaft drum. In the moving status during the picking operation of the pepper harvester, the SSE of the four-shaft drum increased by 3.6%, the PTR decreased by 9.1%, and the DR increased by 3.8% compared to the three-shaft drum, so an improvement in the pepper stem-separation capacity was observed. Full article

Water supply is a primary contributor to the growth and phytonutrient composition in chili peppers. Several physiological stress factors can influence phytonutrients in chili peppers, resulting in their differential synthesis. Maintaining the right and exact amount of water through a drip system can promote an effective fruit set and crop quality. Four pepper cultivars (‘Hetényi Parázs’; HET, ‘Unikal’; UNIK, ‘Unijol’; UNIJ and ‘Habanero’; HAB) were investigated under different water supply treatments: RF or rain-fed, DI or deficit irrigation, and OWS or optimum water supply. The two-year experiment was carried out in May 2018 and 2019 under open field conditions. Physiological parameters (relative chlorophyll content, chlorophyll fluorescence, and canopy temperature) were measured during the growth stage and phytonutrients (vitamin C, capsaicinoids and carotenoids) analyzed using high-performance liquid chromatography (HPLC) at harvest in September. The study revealed that, due to higher precipitation and rainfall interruption, increased water supply affected physiological response and phytonutrients in the cultivars. HAB under OWS had a lower response during the growth period when compared to HET, UNIK, and UNIJ. As water supply increased, measured individual carotenoid concentration increased in some cultivars. On the other hand, as water supply decreased, vitamin C and capsaicinoids concentration increased. Even though cultivars responded to the water supply treatments differently, HET exhibited a more uniform and stable composition in all treatments. Full article

The species belonging to the genus Capsicum have been widely used as decorative vegetables, however only a few genotypes are available for this purpose. The goal of the present work was the agro-morphological characterization of several chili pepper accessions cultivated into different pot sizes (10, 14, 18 or 20 cm diameters). The agro-morphological characterization of 19 accessions was performed following IPGR (International Plant Genetic Resources Institute) descriptors: plant height (PH), plant canopy width (PCW), PH/PCW ratio, plant growth habit, plant visual quality, first flower emission, fruiting start, end of harvest, fruit number, fruit length, fruit width, fruit color at mature stage and fruit shape. Analysis of Variance (ANOVA) for all observed traits showed statistical significant differences among the genotypes tested. Results of the heat map complementarily secured the frequency of multiplicity highlighted from the ANOVA analysis. Furthermore, the present study pointed out that A33, A27, G1 and A1 chili pepper accessions achieved optimal performances in terms of plant visual quality, which is a crucial trait for ornamental purposes. Full article

Chili pepper is produced by family farmers in central Chile incorporating modern technologies and maintaining traditional practices. Although chili pepper is deeply rooted in the local culture, the agricultural system supporting its production and the germplasm involved are poorly studied. This work focused on two main landraces lacking information about what features (agronomic, morphological and chemical) distinguish them and how distinct they are. It is also of high importance to deepen our understanding of the agricultural system and the aspects that may affect its sustainability. An integrated approach was applied for the evaluation of social characteristics of farmers, the growing system, morphological traits, and selected chemical components. Between landraces, flower and fruit morphology was clearly distinct. Total phenolic content, antioxidant capacity and total carotenoid content showed higher values in fruits of cacho de cabra than in chileno negro. Both landraces had a higher total phenolic content than other Capsicum cultivars in the world. Farmers ascribe distinct attributes for the landraces regarding agronomic performance, fruit quality and processing applications. Characteristics that may affect the sustainability of the agricultural system are small farm size, relatives working as employees, and low farmers’ educational attainment. The study landraces are distinct and represent unique genetic material produced in an agricultural system facing important challenges where farmers have adapted to socio-economic pressures, externalizing plant production, reducing harvest costs, and developing innovations in product and marketing. Full article