Mature Fruit Research Articles

The Identification, Separation, and Clamp Function of an Intelligent Flexible Blueberry Picking Robot

Identifying fruit maturity accurately and achieving damage-free harvesting are challenges in designing blueberry-picking robots. This paper presents an intelligent flexible picking system. First, we trained a deep learning-based YOLOv8n network to locate the position of the fruit and determine fruit ripeness. We used a neural network to establish the relationship between fruit hardness and shape parameters, achieving an adaptive gripping force for different fruits. To address the issue of dense clusters in some blueberry varieties, we designed a fruit separation subsystem using a combination of flow field analysis and pressure-sensitive experiments. The results show that the mean average precision can reach 84.62%, the precision is 94.49%, the recall is 83.85%, the F1 score is 88.85%, and the test time is 0.12 s, which can meet the requirements for blueberry fruit recognition accuracy and speed. The spacing between closely packed fruits can increase by 4 mm, and the damage-free picking rate exceeds 92%, achieving stable, damage-free harvesting.

Genetic Characterization and Fruit Quality Analysis of New Mandarin Hybrids

Mandarin fruits with good physicochemical quality are desired for the fresh fruit market. The ease of crosses among citrus taxa has been used to expand genetic variability and select new varieties for different fruit markets. With the aim of selecting new commercial varieties, eleven hybrids obtained from the cross between Murcott tangor and Ponkan mandarin were grafted on Rangpur lime rootstock and evaluated for genetic and phenotypical characteristics. It was observed that there are significant differences in the fruit shape, content, and organoleptic characteristics in juice and differential responses to Alternaria alternate, the causal agent of the Alternaria brown spot (ABS) disease. The phenotypic and molecular characterization showed two groups of hybrids, those that resemble Ponkan and others with characteristics closer to the parental Murcott. There are significant differences in the period of fruit maturation among the hybrids and their parents. Considering the parents stand out as the main commercial varieties in the Brazilian mandarin fresh fruit market, these new hybrids have great potential for commercial acceptance and could be an excellent option to extend the period of supply of mandarins. Genetic and phenotypical information will be fundamental for the registration and/or protection of new varieties, which are essential steps that precede the commercial release to the producer.

Demonstration of Local Honeybee Flora “Mentesie” (<i>Becium grandflorum</i>) Propagation Techniques in Wag - Himra Zone, Ethiopia

The demonstration of local honeybee flora "Mentesie" (<i>Becium grandiflorum</i>) propagation techniques was carried out over two rainy seasons in the Gazgibla district, Debreweyla watershed closure area of the Northeastern Amhara region. The shrub has numerous benefits for the community, including honey production, fuel use, and soil and water conservation. However, it has been gradually declining. To preserve these valuable shrubs, various propagation techniques were tested. The objectives of the experiment were to demonstrate the propagation techniques of <i>Becium grandiflorum</i> to beekeepers and to generate wider demand for its plantation among beekeepers and extension workers. The experiment compared two selected propagation techniques with local farmers’ traditional planting practices, under the guidance of forestry researchers. The treatments included seeds and cuttings. Seeds were collected from mature fruits, and cuttings were taken early in the morning from natural, mature, young, and healthy mother plants at a height of 40 cm during 2020/21. These materials were packed in perforated polyethylene bags. The average mean of flower numbers, branch numbers, and canopy cover for the enhanced propagation techniques (seedlings with pots) were 4107, 21.81, and 92.5, respectively. These values were higher than those for the comparative propagation technique, which had flower numbers of 2462, branch numbers of 19.4, and a canopy cover of 92.5. There were significant differences (p<0.05) among the propagation techniques in terms of canopy cover, height, number of flowers, and branches per plant. Farmers recognized the higher flower biomass, canopy cover, and potential for greater plant height of the enhanced techniques, which are beneficial for bee forage and soil and water conservation. Therefore, planting seedlings using pots were found to be the best method for the wider production of <i>B. grandiflorum</i> in its natural growing areas.

Quantification and histochemical localization of secondary metabolites during development in Annona muricata L. (Annonaceae).

Histolocalization and quantification of secondary metabolites established the occurrence of alkaloids, phenols and acetogenins in various plant organs of A. muricata at different stages of plant growth. Annona muricata L. possesses broad assemblage of ethno-pharmaceutical and therapeutic upsides ascribed to biosynthesis of secondary metabolites. Currently, the bioactivity is characterized by the production of acetogenins (ACGs), and also by the biosynthesis of alkaloids, primarily benzylisoquinolines derived from tyrosine and phenolic compounds. As a result of high variability of metabolite production in A. muricata, the present study evaluated the histochemical analysis of various plant parts at different developmental stages of growth. Presences of phytometabolites were determined using in-situ histochemical localization of alkaloids, phenolic compounds and acetogenins, while its estimation employing spectroscopic quantification techniques to understand structure, development, time-course deposition, content and distribution of secondary phytoconstituents. Study revealed distinct presence of secondary metabolites in cells and tissues of all plant organs in various intensities and patterns. Alkaloids and acetogenins occurred mostly in secretory cavities or idioblast cells while sparsely associated with other cells or tissues. Phenolic compounds emerged widely, with no confined distribution patterns occurring in storage cells and tissues. Quantitative analysis revealed highest accumulation of alkaloids, phenols and acetogenins in mature root-barks, mature unripe fruit rind and mature leaf respectively. Secondary metabolites generally occurred in young stages at low concentrations as compared to matured growth stages of plant parts. Such in-situ histochemical and biochemical approach will help in identifying the cells and tissues responsible for synthesis, storage and biological effects of potential secondary metabolites which could be further used for culturing and enhancing its production with biotechnological aids.

Precision harvesting: comparative analysis of machine learning and generative AI-based classifiers for guava fruit maturity assessment using thermal imaging

ABSTRACT Guava is a highly nutritious fruit with abundance of health benefits and is medically recommended for daily consumption. Therefore, quality assessment of guava is of significance. Manual quality grading of fruits is being performed for a long time which suffers from subjective biases. Consequently, development of a computer vision-based automated system for quality grading of fruits is essential. In this paper, maturity assessment of guava is performed using various machine learning classifiers, including neural network, fuzzy logic system, and generative AI models. Thermal images of guava are used for maturity assessment. Performance of these models is evaluated by determining the confusion matrix and classification report, considering both class-wise and overall classification. After careful observation, FLS-based ANFIS is highly recommended for grading the guava on the basis of its maturity level. Furthermore, thermal imaging is also very significant for the development of a holistic computer vision-based fruit quality assessment model.

Vegetative and reproductive morphology of Othniophyton elongatum (MacGinitie) gen. et comb. nov., an extinct angiosperm of possible caryophyllalean affinity from the Eocene of Colorado and Utah, USA.

Eocene foliage formerly attributed to the extant araliaceous genus Oreopanax was found attached to twigs bearing inflorescences and infructescences unlike those of Araliaceae. Using newly observable characters of phyllotaxy, vegetative and floral buds, infructescences and seeds, we sought to reassess the affinities of this strange angiosperm. Fossils were studied from the Parachute Creek Member of the Green River Formation from near Bonanza, Utah and Douglas Pass, Colorado (ca. 47 Ma). Macrofossil impression remains were investigated by low angle reflected light and subtle details of the vegetative and floral buds, stamens, mature fruits, and seeds were revealed by optical shadow effect microscopy documenting previously obscure topographic surface features. Othniophyton elongatum (MacGinitie) Manchester, Judd, Correa-Narvaez gen. et comb. nov. has simple, short-petiolate, elongate, entire-margined leaves with thick midveins, pinnate, brochidodromous secondaries, common intersecondary veins and finely reticulate higher order venation. Inflorescences are small axillary cymes; flower buds are subglobose and pedicellate, in bract axils. The flowers are actinomorphic, bisexual, with ca. five imbricate perianth parts, ca. 24 stamens with elongate anthers and short filaments, arising from a hypanthium. The whorl of stamens persists to fruiting stage. The ovary is superior, with probable basal placentation and five stigmatic arms. Fruits are pedicellate berries with a cup-shaped hypanthium and contain ca. 15 lensoidal reniform seeds, each with a curved embryo and ornamented with concentric ridges. The combined characters refute the prior placement in Araliaceae, and rule out affinities with most extant clades of angiosperms. The distinctive combination of observed features does not coincide with any extant family. Among extant orders of Eudicots, the fossil seems to conform most closely to the order Caryophyllales, but key differences remain. This example indicates that the vegetation of ca. 47 million years ago included some taxa that cannot readily be placed in modern families and genera.

Morphological, molecular and 3D synchrotron X-ray tomographic characterizations of Helicascus satunensis sp. nov., a novel mangrove fungus.

A new species of Helicascus satunensis sp. nov. was collected on mature dead fruits of the Nypa palm in Satun Province, southern Thailand. Its morphological characteristics are similar to those of the genus Helicascus. Recently, a genus Helicascus with three species from marine habitats worldwide was studied. The morphology of this fungus was investigated and combined with multigene sequence analyzes of small subunit (SSU), large subunit (LSU), internal transcribed spacer (ITS) ribosomal DNA, translation elongation factor 1-alpha (TEF-1α) and RNA polymerase II (RPB2) genes. Morphologically, H. satunensis sp. nov. is characterized by semi-immersed, lenticular ascomata, multilocules, a bitunicate ascus and smooth, obovoid, dark brown ascospores that are one-septate and unequally two-celled. In addition, 3D visualization using synchrotron X-ray tomography was performed to investigate the interaction between fruiting body and substrata. Molecular phylogeny with multigene revealed that H. satunensis sp. nov. belongs to the family Morosphaeriaceae, order Pleosporales, class Dothideomycetes. Furthermore, H. satunensis sp. nov. forms a well-supported clade with Helicascus species described from marine habitats. Based on the unique morphological and molecular evidence, we propose this fungus, H. satunensis sp. nov., as a new species for Helicascus.

Scab Intensity in Pecan Trees in Relation to Hedge-Pruning Methods.

Pecan is a valuable nut crop cultivated in the southeastern United States. Among the major yield-limiting factors in the region is scab, caused by the plant pathogenic fungus Venturia effusa. Managing scab in tall trees (15 to 25+ m) in pecan orchards is challenging because of the limitations of getting sufficient spray coverage throughout the canopy. We explored the effects of hedge pruning on scab in three orchards: 14-m-tall cv. Desirable trees winter hedge pruned on alternate sides to 11 m (site 1), 18-m-tall cv. Stuart trees hedge pruned on both sides simultaneously to 11 m (site 2), and 15-m-tall cv. Caddo trees winter hedge pruned in winter versus summer to 11 m (site 3). At site 1 and 2, hedge-pruned trees were compared with nonpruned control trees. All trees received recommended fungicide applications to control scab via an air-blast sprayer. Disease incidence and/or severity was assessed at different sample heights on shoots, foliage, and fruit during three seasons (2020, 2021, and 2022). At site 1 the hedge-pruned trees often had significantly or numerically more severe scab on foliage and fruit compared with the control trees, although the differences were mostly small. The frequency of mature fruit with scab severity <10% was greatest on control trees in 2021 and 2022. At site 2, there were few differences between hedge-pruned and control trees (on fruit, scab severity was either significantly less on hedge-pruned trees or not different from the control), but the frequency of mature fruit with scab severity <10% was consistently greatest on hedge-pruned trees. At site 3, scab intensity was low, and there were no significant differences in scab severity between winter- and summer-pruning treatments. At sites 1 and 2, there was generally more severe scab at greater sample heights compared with low in the canopy. At site 3 there was little effect of height on disease. The benefit of hedge pruning likely increases with tree height in scab-susceptible cultivars. If a tree is taller than ∼15 m, a greater proportion of the fruit will be within reach of efficacious spray coverage from air-blast sprayers.

Genome-Wide Analysis of the Common Fig (Ficus carica L.) R2R3-MYB Genes Reveals Their Structure, Evolution, and Roles in Fruit Color Variation.

The R2R3-MYB transcription factor (TF) family is crucial for regulating plant growth, stress response, and fruit ripening. Although this TF family has been examined in a multitude of plants, the R2R3-MYB TFs in Ficus carica, a Mediterranean fruit species, have yet to be characterized. This study identified and classified 63 R2R3-MYB genes (FcMYB1 to FcMYB63) in the F. carica genome. We analyzed these genes for physicochemical properties, conserved motifs, phylogenetic relationships, gene architecture, selection pressure, and gene expression profiles and networks. The genes were classified into 29 clades, with members of the same clade showing similar exon-intron structures and motif compositions. Of the 54 orthologous gene pairs shared with mulberry (Morus notabilis), 52 evolved under negative selection, while two pairs (FcMYB55/MnMYB20 and FcMYB59/MnMYB31) experienced diversifying selection. RNA-Seq analysis showed that FcMYB26, FcMYB33, and FcMYB34 were significantly overexpressed in fig fruit peel during maturation phase III. Weighted gene co-expression network analysis (WGCNA) indicated that these genes are part of an expression module associated with the anthocyanin pathway. RT-qPCR validation confirmed these findings and revealed that the Tunisian cultivars 'Zidi' and 'Soltani' have cultivar-specific R2R3-FcMYB genes highly overexpressed during the final stage of fruit maturation and color acquisition. These genes likely influence cultivar-specific pigment synthesis. This study provides a comprehensive overview of the R2R3-MYB TF family in fig, offering a framework for selecting genes related to fruit peel color in breeding programs.

Multi-omics analysis provides insights into the mechanism underlying fruit color formation in Capsicum

Fruit color is a crucial attribute of fruit quality in peppers (Capsicum spp.). However, few studies have focused on the mechanism of color formation in immature pepper fruits. In this study, the light-yellow color observed in immature CSJ009 fruits compared to CSJ010 could be attributed to decreased chlorophyll and carotenoid pigments. Through integrated analysis of the transcriptome and metabolome of CSJ009 and CSJ010, we identified 23,930 differentially expressed genes (DEGs) and 345 differentially accumulated metabolites (DAMs). Furthermore, integrated analysis revealed a strong correlation between the HCT-like gene and metabolite MWS0178 (chlorogenic acid). Paraffin section assay revealed that the epidermal cells of immature CSJ010 fruits exhibited a more compact arrangement with significantly greater length than those of CSJ009. Quantitative determination of carotenoids showed that lutein emerged as the predominant carotenoid in immature pepper fruits. Additionally, missense mutation of LCYB2 is likely to lead to a decrease in β-carotene content in immature CSJ009 fruits, whereas CCS may directly catalyze the conversion of lycopene to β-carotene in mature fruits. The null mutation in CCS promoted the biosynthesis of β,ϵ-branch carotenoids leading to lutein being the most abundant carotenoid found in orange CSJ010 fruits. These findings provide important insights into the mechanism underlying color formation in pepper fruits and establish a foundation for the further exploration of color-related genes.

Metabolome and transcriptome reveal the biosynthesis of flavonoids and amino acids in Isatis indigotica fruit during development.

Isatis indigotica Fort. is a famous medicinal plant that is also used as a natural dye and functional vegetable. The characteristics of the I. indigotica fruit during development are largely unknown, information that is essential for the exploitation and seedlings cultivation of I. indigotica. In this study, the biochemical, metabolite characteristics and gene expression profiling of I. indigotica at four developmental stages were investigated. A total of 428 metabolites were detected and categorized into 17 categories. High contents of anthocyanins, especially cyanidin 3-glucoside, might contribute to the purple colouration of I. indigotica fruits. Moreover, dozens of flavonoid components, including taxifolin, quercetin, astragalin and isovitexin 2″-O-beta-D-glucoside, and several other active components were also up-regulated in mature fruits. The abundance of antioxidants might endow a significantly stronger antioxidant activity of mature I. indigotica fruits compared to many other reported species. Enrichment analyses revealed that flavonoid and anthocyanin biosynthesis genes were mostly enriched in up-regulated gene sets during fruit development. The up-regulated structural genes, including IiCHS, IiCHI, IiF3H, IiDFR, IiANS, IiFLS, IiUGT, and transcription factors such as IiMYBs, IibHLHs and IiNACs were identified as candidate regulators of flavonoid and anthocyanin biosynthetic pathway. Furthermore, biosynthesis of amino acids was enriched in all pairwise comparisons of metabolites in fruits at four developmental stages. The differential accumulation of amino acids might result from the differentially expressed genes involved in amino acid biosynthesis. Taken together, these findings provide a comprehensive understanding of metabolite profiling and gene expression patterns in I. indigotica fruit during maturity, which is useful for pharmaceutical extractions and seedling cultivation of I. indigotica.

ZF protein C2H2-71 regulates soluble solids content by inhibiting LIN5 in tomato

Soluble solids content (SSC) plays an important role in determining the flavor of tomato fruits. Tomato fruit SSC has been shown to be transcriptionally regulated via sugar metabolism. Previous studies have been predominantly focused on the role of C2H2-type zinc finger proteins in tomato growth and development. However, the specific regulatory mechanism of C2H2 in the accumulation of soluble solids in tomato fruits are yet to be fully understood. This study involved the selection of eight tomato accessions with varying levels of SSC to study the expression of SlC2H2 family genes in red ripe fruits. The study found that the levels of SlC2H2-71 expressions were significantly reduced in high-SSC accessions compared to low-SSC accessions. The Slc2h2-71 mutant lines were developed using the CRISPR-Cas9 system, leading to elevated levels of soluble solids, fructose, glucose, malic, and citric acids in mature red ripe fruits. However, sucrose content in the edited Slc2h2-71 mutant lines generally decreased. RNA-seq analysis revealed that fruits from the mutant lines had altered expression of genes related to sugar and acid metabolic pathways, which was further confirmed by quantitative real time PCR. Specifically, there was an observed increase in the expression of SlLIN5 encoding the cell wall invertase (CWIN). The yeast one-hybrid (Y1H) assay, 35S::UAS-GUS, dual-luciferase reporter systems and electrophoretic mobility shift assay (EMSA) demonstrated that SlC2H2-71 regulates tomato sugar metabolism by directly binding to the promoter region of SlLIN5, culminating in the repression of its transcriptional activity. The activity of acid invertase in the SlC2H2-71 knock-out lines exhibited a significantly higher level compared to that observed in the control lines. In summary, the regulation of tomato fruit SSC by SlC2H2-71 involves the inhibition of SlLIN5 expression.

Drought-mediated oxidative stress and its scavenging differ between citrus hybrids with medium and late fruit maturation

Drought stress is a major environmental factor limiting citrus productivity. Still, differences in drought sensitivity between citrus hybrids of different maturation periods have so far not been reported. Here, we selected a medium-maturing (Fertile orange: FO (Citrus reticulata cv. Fertile orange) and a late-maturing citrus hybrid (Newhall Navel orange: NO (Citrus sinensis Osbeck cv. Newhall) and determined the physiological and biochemical traits of leaves, roots, wood and bark. Our results showed that drought significantly decreased net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of citrus leaves. Oxidative stress upon drought was indicated by enhanced foliar malondialdehyde (MDA) and hydrogen peroxide contents, as well as a stimulation of the anti-oxidative system. This stimulation included the contents of dehydroascorbic acid (DHA), glutathione (GSH) and oxidized glutathione (GSSG) in leaves, roots, wood and bark, as well as activities of antioxidative enzymes of glutathione reductase (GR), dehydroascorbate reductase (DHAR), superoxide dismutase (SOD) and peroxidase (POD). The late maturing NO hybrid not only showed better general physiological performance as indicated by increased Pn in leaves, but also higher biochemical ROS scavenging and osmotic capacity as indicated by increased ascorbic acids (ASA), DHA, and proline contents, as well as activities of enzymes of SOD, POD, ASA/DHA and GSH/GSSG ratios in the investigated tissues compared to the FO hybrid under drought and control conditions. Analysis of molecular mechanisms of signaling, regulatory and functional genes expression are suggested for future studies to elucidate the complex interplay of molecular, biochemical and physiological responses of citrus hybrids to drought.

Relationships Between Organic Acid Metabolism and the Accumulation of Sugars and Calcium in Fruits of Cerasus humilis During Different Development Stages.

Cerasus humilis fruit is known for its high acidity, surpassing that of most other fruits. The metabolism of organic acids in these fruits significantly influences sugar and calcium accumulation. However, research on this metabolic process is limited. This study investigates the organic acid metabolism and the accumulation patterns of sugars and calcium during the development of Cerasus humilis fruits. Using low-acid and high-acid varieties from Inner Mongolia, we compared organic acid components and the activity of relevant metabolic enzymes during fruit maturation. We also measured the content and proportions of various sugars and calcium forms, performing correlation analyses. Throughout the development and ripening of Cerasus humilis fruits, organic acids, sugars, and calcium exhibited consistent patterns of change across the two acidity types. Malic acid emerged as the most significant organic acid, while fructose was the primary sugar, and active calcium was the dominant calcium component. Correlation analyses indicated that malic acid and total acid positively correlated with sugar and water-soluble calcium content, negatively regulating other calcium forms. Conversely, NADP-ME, citric acid, and oxalic acid negatively correlated with sugars and water-soluble calcium, while positively affecting other calcium forms. In conclusion, the metabolism of organic acids during the development and maturation of Cerasus humilis fruits is closely linked to the accumulation of sugars and calcium. Malic acid, primarily regulated by NAD-MDH and NADP-ME, promotes the accumulation of sugars and water-soluble calcium but inhibits other calcium forms, while citric and oxalic acids inhibit sugar accumulation and promote non-water-soluble calcium forms.

Advances in Lycium Barbarum Polysaccharide in the Prevention and Treatment of Ophthalmic Diseases

Lycium barbarum is the dried mature fruit of Ningxia wolfberry, family Solanaceae. Chinese medicine believes that wolfberry has the effect of nourishing the liver and kidney, benefiting the essence and brightening the eyes. Lycium barbarum polysaccharide (LBP) is a proteoglycan isolated from Chinese medicine goji berry, which is the most important active ingredient in goji berry extract, with antioxidant, anti-inflammatory, anti-aging, anti-tumor, protection of the nervous system, protection of the retina, hypoglycemia, hypolipidemia, enhancement of immunity and other effects. In recent years, research results about LBP in the prevention and treatment of ophthalmic diseases have been emerging, such as cataract, glaucoma, diabetic retinopathy, macular degeneration has a certain preventive and therapeutic effects. This paper analyzes and reviews the relevant literature on LBP in the prevention and treatment of ophthalmic diseases.

Characterization of Free and Glycosidically Bound Volatile and Non-Volatile Components of Shiikuwasha (Citrus depressa Hayata) Fruit.

Shiikuwasha, a citrus fruit native to Okinawa, Japan, has various cultivation lines with distinct free volatile and non-volatile components. However, the glycosylated volatiles, which are sources of hidden aromas, remain unknown. This study aimed to characterize the chemical profiles of free and glycosidically bound volatile as well as non-volatile components in the mature fruits of six Shiikuwasha cultivation lines: Ishikunibu, Izumi kugani-like, Kaachi, Kohama, Nakamoto seedless, and Ogimi kugani. Free volatiles were analyzed using solid-phase microextraction-gas chromatography-mass spectrometry. Glycosides were collected via solid-phase extraction and hydrolyzed with β-glucosidase, and the released volatiles were measured. Additionally, the non-volatile components were determined using non-targeted proton nuclear magnetic resonance analysis. Total free and bound volatiles ranged from 457 to 8401 µg/L and from 104 to 548 µg/L, respectively, and the predominant free volatiles found were limonene, γ-terpinene, and p-cymene. Twenty volatiles were released from glycosides, including predominant 1-hexanol and benzyl alcohol, with Kaachi and Ogimi kugani showing higher concentrations. Principal component analysis (PCA) revealed that taste-related compounds like sucrose, citrate, and malate influenced line differentiation. The PCA of the combined data of free and bound volatile and non-volatile components showed flavor component variances across all lines. These findings provide valuable insights into the chemical profiles of Shiikuwasha fruits for fresh consumption and food and beverage processing.

Mapping and cloning of pepper fruit color-related genes based on BSA-seq technology.

Fruit color is an important qualitative trait that greatly influences the marketability of peppers. Fruit color can be divided into two categories. Green fruit color denotes commercial maturity, whereas ripe fruit indicates physiological maturity. Herein, segregation populations were created using the 'D24' with pale green in the green fruit stage, orange in the mature fruit stage, and 'D47' with green in the green fruit stage and red in the mature fruit stage. BSA-seq and genetic linkage map analysis revealed green fruit color was linked to (gyqtl1.1) on Chr1 and (gyqtl10.1) on Chr10, while mature fruit color was linked to Chr6. Using functional annotation, sequence, and expression analysis, we speculate that an SNP mutation in the CapGLK2 gene at the gyqtl10.1 interval could initiate premature termination of translation, thus yielding green to pale green fruits in D47. Conversely, the orange color in mature D24 fruits is due to the Indel-mediated premature termination of translation of the CapCCS gene. Our research offers a theoretical foundation for choosing different varieties of pepper fruit based on their color.

Sources and splitting of special fertilizers application in coffee crop

This study assesses special and mineral fertilizers and the splitting of fertilizer application in coffee - a crop with high nutritional requirements for full yield potential. A 4 × 3 factorial scheme was implemented with four fertilizers [mineral, mineral with polymer, organomineral with cellulosic residue (OM-CR), or sugarcane filter cake (OM-FC)] and three application times, or splits (100% at once, 50%+50%, 33.3%+33.3%+33.3%). Coffee plant height, canopy diameter, plagiotropic branch growth, leaf chlorophyll, nutrient contents in the soil and leaves, and harvest yield after fruit maturation were evaluated in two consecutive crop cycles. The results indicated that organomineral fertilizers performed similarly to other fertilizers regarding coffee leaf chlorophyll and plant height. Only one fertilizer application effectively increased canopy diameter in both crop cycles. In the first crop cycle, OM-FC and conventional mineral fertilizers were significantly better for coffee foliar N content. In contrast, in the second crop cycle, mineral-P, OM-CR, and OM-FC achieved satisfactory results with one fertilizer application, whereas conventional mineral fertilizer required three applications for superior results. There are no differences in leaf P content among different sources and frequencies of application. Still, mineral-P and OM-CR had better soil P content than the conventional mineral fertilizer. OM-CR required two applications to reach high levels of leaf K content, while other fertilizers achieved it with one application. Organomineral and protected mineral fertilizers performed similarly in both crop cycles, with two applications resulting in greater coffee yield in the second cycle, regardless of the fertilizer used.

Assessing Nitrogen Fertilization in Processing Pepper: Critical Nitrogen Curve, Yield Response, and Crop Development

Groundwater pollution in intensive horticultural areas is becoming an increasingly important problem. Over-fertilization of these crops, combined with poor irrigation management, leads to groundwater contamination through leaching. Previous research on the effect of N on sweet peppers grown in greenhouses is abundant, but data on outdoor cultivation, especially considering variety and site influences, are lacking. Therefore, this study evaluates nitrogen (N) fertilization in open-field processing-pepper crop in Extremadura, Spain to mitigate this environmental impact. Field trials were conducted in 2020, 2021, and 2022 to determine the optimum N fertilizer rate for processing peppers, with the aim of reducing environmental impacts such as nitrate leaching while maintaining crop yields. The trial consisted of applying different N doses, 0, 60, 120, and 180 kg N/ha in 2020 and 2021 and 0, 100, and 300 kg N/ha in 2022. There were four replications of each treatment, arranged in randomized blocks. Measurements included crop yield, biomass, intercepted photosynthetically active radiation (PAR), and canopy cover. The study also developed a critical nitrogen curve (CNC) to determine the minimum N concentration required for optimal growth. The commercial yield results showed that there were no significant differences between the two treatments with higher N inputs in the three years; therefore, the application of more than 120 kg N/ha did not significantly increase yield. Nitrogen-free treatments resulted in earlier fruit maturity, concentrating the harvest and reducing waste. In addition, excessive N application led to environmental problems such as groundwater contamination due to nitrate leaching. The study concludes that outdoor pepper crops in this region can achieve optimal yields with lower N rates (around 120 kg N/ha) compared to current practices, taking into account that initial soil N values were higher than 100 kg N/ha, thereby reducing environmental risks and fertilizer costs. It also established relationships between biomass, canopy cover, and N uptake to improve fertilization strategies. These data support future crop modeling and sustainable fertilization practices.

Detection, counting, and maturity assessment of blueberries in canopy images using YOLOv8 and YOLOv9

Blueberry growers currently rely on manual or subjective approaches to harvest decision-making and yield estimation. Canopy image-based, pre-harvest blueberry detection provides a promising means for automated harvest maturity assessment, fruit counting, and yield estimation to optimize crop management and reduce labor costs. Data-driven deep-learning-based object detectors, especially the YOLO (You Only Look Once) series models, have emerged as a powerful tool for a diversity of computer vision tasks in agriculture. However, the detection of such small, densely populated objects as blueberries in unstructured scenes can pose great challenges, especially given the lack of dedicated datasets for model development. This study, therefore, presents the first publicly available dataset of blueberry canopy images with 17,955 ripe and unripe blueberries, which were captured in diverse orchard conditions, and performance evaluation of YOLOv8l (large) and YOLOv9-c (compact) with comparable complexity for blueberry detection and whereby fruit counting and ripe fruit percentage estimation. At the input image resolution of 2560 × 2560 pixels, both models performed similarly in terms of detection accuracy with around 91 % mAP@50, except that YOLOv9-c was far more time-consuming to train. Trained with the input of higher resolution images of 3520 × 3520 pixels, YOLOv8l achieved an overall mAP@50 of nearly 93 %, and an RMSEs (root-mean-square errors) of 10.4 in fruit counting and 3.62 % in estimating the percentage of ripe fruit of each image. Both the blueberry dataset11https://zenodo.org/records/14002517 and software programs22https://github.com/vicdxxx/BlueberryDetectionAndCounting of this study have been or will be made publicly available, which are expected to be useful for promoting greater community efforts for further algorithm development.