Citrus Reticulata Research Articles

Adoption of soil conservation practices by mandarin (Citrus reticulata B.) farmers in Gulmi, Nepal

Mandarin has a tremendous potential for export and increased income for farmers of Nepal. However, in the recent years, soil degradation and erosion are the major challenges faced by the citrus enterprises especially in the hilly region of Nepal. The declining status of production and productivity cannot be checked without the transfer of site-specific and commodity-based knowledge and skills to the corresponding farmers. A study was carried out in 2023 to examine the soil conservation practices and status of technology adoption among the mandarin farmers. A total of 80 households from three wards of Dhurkot rural municipality of Gulmi district were selected on purpose for the study. Data were collected through interviews, key informant interviews, and focus group discussion, using semi-structured questionnaire, then the descriptive analysis was done using MS Excel and SPSS (Version 23.0). The results revealed that mainly three types of soil were presented in the study areas viz. luvisols, cambisols and sandy gravel, which are highly prone to soil erosion. The average area under mandarin cultivation was reported to be 0.74 hectare, with an estimated productivity of 7.6 metric tons per hectare. Approximately 95% of the respondents were familiar with soil degradation and its consequences in mandarin production. Accordingly, 96.2% of the respondents had adopted some forms of soil conservation practices like sod culture (40%), minimum tillage (36.2%), liming (40%), terracing and cover cropping (95%) and integrated plant nutrient system (31.2%), alongside the traditional stone bunds and mulching. The findings suggested that an increased participation in trainings and contact with extension agents has a significant influence on the importance of capacity building of the farmers regarding sustainable soil conservation technology, innovative cultivation practices, and ensuring frequent extension services to the farmers. Implementing these measures is expected to enable mandarin farmers in Nepal to check annual losses of soil fertility due to soil erosion and landslides, thereby contributing to commercialization of citrus.

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.

Chemical Quality Parameters of Mandarin (Citrus reticulata Blanco.) Fruits Influenced by different Organic Sources

A field experiment was carried out during the year 2021-22 and 2022-23 on 12 years old mandarin plants at the Instructional Farm, Department of Fruit Science, College of Horticulture and Forestry, Jhalawar. The experiment was consisting of 21 treatments of different organic source of NPK viz., vermicompost, cotton fortified vermicompost, neem cake, cotton cake, mustard cake and bio fertilizers such as PSB and VAM with three levels of recommendation dose of fertilizers. The experiment was laid out in randomized block design with three replications. Among different treatments, treatment T9 (75 % RDF + 10 kg Vermicompost + 7.5 kg Neem cake + 50 g PSB) was found best with regards to maximum pooled TSS (11.74 0B), reducing sugar (6.30%) non-reducing sugar (2.62%), total sugar (8.92%) per cent, sugar/acid ratio (14.40), ascorbic acid (53.08mg/100g) and juice (46.57%). Therefore, based on two years experimentation, use of organic source of nutrients with bio-fertilizers favoured biochemical compounds of Nagpur Mandarin fruits.

Association of greening bacterium with fruit morphological disorder ‘Waywar’ in monsoon cropping of Nagpur mandarin (Citrus reticulata Blanco) grown in central India

Abstract In the Vidarbha region of Maharashtra and the surrounding parts of central India, Waywar (citrus greening bacterium) fruit disorder, also known as wasteful fruit disorder, is a common manifestation of Nagpur mandarin fruit. In Vidarbha, the condition is also known as cock bund, while in China, it is called ‘Red Nose.’ According to early research, this condition is caused by abiotic stress factors, such as poor nutrition, too much moisture in the root zone, and other incorrect cultural practices. Recent research, however, has unequivocally shown that Candidatus Liberobacter asiaticus, the citrus greening bacterium, is responsible for this illness. When compared to normal growing fruits (0.82–0.89), the length to diameter ratio of Waywar fruits at the peak of incidence was reported in the range of 0.95–1.09, indicating their oblong shape. Premature Waywar fruits had higher acidity levels (1.75 to 2.04%) than normal fruits (1.65 to 2.03%) and produced seeds that were not viable. The cultural treatments applied to reduce the ill effects of the disorder improved the physico-chemical characteristics of Nagpur mandarin fruit at the time of harvesting. When compared to the untreated control, foliar spraying with growth regulators 2,4-D (15 ppm) and GA3 (15 ppm) enhanced the amount of fruit retained per plant at harvest. The critical fruit quality parameters like TSS (10.10%) and vitamin C (39.37 mg/100 ml) were highest in GA3 treated fruits. Maximum TSS/Acid ratio (14.00) and minimum acidity (0.69%) were noted with phosphorus applied at three times the RDF level at harvest.

A comparison of pericarp anatomy and antioxidant responses after mandarin (Citrus reticulata Blanco) and orange (Citrus sinensis Osbeck) fruits sunburned

A comparison of pericarp anatomy and antioxidant responses after mandarin (Citrus reticulata Blanco) and orange (Citrus sinensis Osbeck) fruits sunburned

Spatiotemporal diversity of bacterial endophyte microbiome of mandarin (Citrus reticulata) in the northern Persian Gulf and its HCN production and N2 fixation.

Endophytes are symbionts that live in healthy plants and potentially improve the health of plant holobionts. Here, we investigated the bacterial endophyte community of Citrus reticulata grown in the northern Persian Gulf. Bacteria were isolated seasonally from healthy trees (root, stem, bark, trunk, leaf, and crown tissues) in four regions of Hormozgan province (i.e., Ahmadi, Siyahoo, Sikhoran, Roudan), a subtropical hot region in Iran. A total of 742 strains from 17 taxa, 3 phyla, and 5 orders were found, most of which belonged to Actinobacteria (Actinobacteriales) as the dominant group, followed by Firmicutes (Bacillales), Proteobacteria (Sphingomonadales, Rhizobiales), and Cyanobacteria (Synechoccales). The genera included Altererythrobacter, Arthrobacter, Bacillus, Cellulosimicrobium, Curtobacterium, Kocuria, Kytococcus, Methylopila, Mycobacterium, Nocardioides, Okiabacterium, Paracraurococcus, and Psychrobacillus. The most frequently occurring species included Psychrobacillus psychrodurans, Kytococcus schroetri, and Bacillus cereus. In addition, the overall colonization frequency and variability of endophytes were higher on the trunks. The leaves showed the lowest species variability in all sampling periods. The frequency of endophyte colonization was also higher in summer. The Shannon-Wiener (H') and Simpson indices varied with all factors, i.e., region, season, and tissue type, with the maximum in Roudan. Furthermore, 52.9% of the strains were capable of nitrogen fixation, and 70% produced antagonistic hydrogen cyanide (HCN). Thus, C. reticulata harbors a variety of bioactive bacterial endophytes that could be beneficial for host fitness in such harsh environments.

Economics of cultivation of mustard varieties (Brassica juncea L.) under Nagpur mandarin (Citrus reticulata Blanco.) based agroforestry system in South-Eastern Rajasthan

Economics of cultivation of mustard varieties (Brassica juncea L.) under Nagpur mandarin (Citrus reticulata Blanco.) based agroforestry system in South-Eastern Rajasthan

The stir-frying process of Citrus reticulata 'Chachi': process optimization, physical and chemical properties, and spectrum-activity relationship

The stir-frying process of Citrus reticulata 'Chachi': process optimization, physical and chemical properties, and spectrum-activity relationship

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.

Transformation of Ponkan Mandarin (Citrus reticulata Blanco) by CRISPR/Cas-9-gRNA-CsCS to increase plant resistance to huanglongbing disease

Transformation of Ponkan Mandarin (Citrus reticulata Blanco) by CRISPR/Cas-9-gRNA-CsCS to increase plant resistance to huanglongbing disease

Toxicity Test of Essential Oil from Kintamani Slayer Orange Peel (Citrus Reticulata) With Zero Waste Application to Support Ecotourism

Kintamani slayer orange peel can be extracted into essential oil because it contains terpenoids, sesquiterpenoids, alkanes, alkyl alkanoates, and steroid alcohols. Orange peel contains active substances that can help heal wounds, such as essential oils, ascorbic acid, vitamin E, vitamin A, flavonoids, and polyphenols, and has antioxidant and antibacterial activity. Kintamani orange peel contains flavonoids, alkaloids, saponins, tannins, terpenoids, and essential oils. The main goal of this study is to identify the waste by-product characteristics of Kintamani slayer orange peel in order to achieve zero waste. Essential oils in Kintamani slayer orange peel (Citrus reticulata) are toxic to Artemia salina Leach shrimp larvae. The GC results on Kintamani slayer orange peel essential oil obtained twelve (12) compound peaks

Application of UV irradiation in preserving Canh oranges (Citrus reticulata)

Application of UV irradiation in preserving Canh oranges (Citrus reticulata)

Impact of Kinnow Production on the Socio-economic Conditions of Farmers in the Agra Region

The cultivation of Kinnow, a hybrid mandarin fruit, in the Agra region has significantly impacted the socio-economic conditions of local farmers. This study examines the effects of Kinnow production on farmer livelihoods in 10 selected villages within the Agra district. Data collected from 100 Kinnow-growing farmers revealed that the crop contributes substantially to income generation, improving the financial stability of farmers. Factors such as landholding size, access to credit, and market linkages influence the profitability of Kinnow orchards. Despite challenges like market fluctuations and environmental conditions, the introduction of Kinnow has provided an alternative source of income for farmers in a semi-arid region. Additionally, this study outlines the costs involved in establishing and maintaining Kinnow orchards, highlighting the initial high investments required, followed by a significant return as orchards mature. The findings suggest that Kinnow production is a viable and profitable agricultural enterprise that can contribute to both economic growth and social development in the region.

Leguminous Green Manure Intercropping Promotes Soil Health in a Citrus (Citrus reticulata) Orchard

The intercropping of green manure is an important and sustainable production method in citrus orchards (Citrus reticulata). However, few studies focus on the impact of annual and perennial green manure on soil health, particularly soil microbiome and properties in acid soil. Our research objective was to explore the potential effects on soil health by intercropping with annual and perennial leguminous green manures in acid soil citrus orchards of southwestern China. The leguminous green manures used were alfalfa (Medicago sativa) and hairy vetch (Vicia villosa). The results showed that intercropping with green manure increased the total nitrogen, nitrate nitrogen, and available phosphorous in the soil by 48.67~74.67%, 50.00~96.67%, and 44.48~45.04%, respectively. Intercropping with alfalfa significantly increased the activity of soil sucrase 63.75%, and intercropping with hairy vetch increased the activity of β-1,4-glucosidase 44.38% in the soil compared to the monoculture treatment. Intercropping hairy vetch and alfalfa altered the diversity and composition of the soil microbial community and enriched the soil with beneficial fungi and bacteria, including Mortierella and Streptomyces. The richness increased by 58.72% and 17.90% in alfalfa intercropping treatment. In conclusion, intercropping leguminous green manure improved the nutrients and activity of the enzymes in the soil and enriched the antagonistic microbiome in the soil, promoting soil health in the citrus orchard.

Fruit Distortion in Nagpur Mandarin (Citrus Reticulata Blanco): A Concern to be Addressed

Fruit Distortion in Nagpur Mandarin (Citrus Reticulata Blanco): A Concern to be Addressed

Immunomodulatory Effects of Citrus Species Ethanol Extracts on Cellular Immune Responses in Wistar Rats and Mice

Currenty, Citrus reticulata has been found to modulate RAW 264.7 macrophage cell line. In the present study, the immunomodulatory effects of Citrus species peel extracts, including Citrus microcarpa, C. limon L., C. sinensis L. and C. hystrix were investigated on cellular immune responses in Wistar rats and mice. Mice were treated with ethanol extracts of Citrus species orally at dosages of 25, 50 and 100 mg/kg bw for 7 days. The phagocytosis activity of the extracts was examined using the carbon clearance method. Meanwhile, oral administration of Citrus species ethanol extracts at dosages of 17.5, 35 and 70 mg/kg bw was administered to Wistar rats to assess the effect of extracts on the delayed-type hypersensitivity (DTH) response using paw edema-method. Thin Layer Chromatography (TLC)-densitometry analysis was also performed. In both animal models, all extracts enhanced the cellular immune responses. Amongst the samples, C. sinensis, at the dose of 100 mg/kg bw in mice and 70 mg/kb bw in rats, demonstrated the highest stimulation on phagocytosis activity and DTH response, respectively. Except C. microcarpa, rutin was found in all Citrus species. The results indicate that Citrus species, particularly C. sinensis, have the potential to be developed into a potent immunostimulatory agent. HIGHLIGHTS The immunomodulatory effects Citrus species were investigated using mice and rats as animal models. Citrus microcarpa, C. limon, C. sinensis L. and C. hystrix were able to stimulate phagocytosis in mice and delayed-type hypersensitivity response in rats. Citrus sinensis demonstrated the highest stimulation on phagocytosis activity and delayed-type hypersensitivity response. Rutin was found in all Citrus species, except in microcarpa peels extract. GRAPHICAL ABSTRACT

Calcium carbonate treatments affect cultivation environment around the fruit surface and mitigate sunburn formation and rind puffing of satsuma mandarin fruits

Calcium carbonate treatments affect cultivation environment around the fruit surface and mitigate sunburn formation and rind puffing of satsuma mandarin fruits

A Comparison of DNA-Methylation during Protoplast Culture of Ponkan Mandarin (Citrus reticulata Blanco) and Tobacco (Nicotiana tabacum L.)

The epigenetic variation in protoplast regeneration is a topic that has attracted interest recently. To elucidate the role of DNA methylation in the regeneration of protoplasts from the ponkan (Citrus reticulata), this study employs the methylation-sensitive amplification polymorphism (MSAP) molecular marker technique to analyze changes in DNA methylation levels and patterns during the isolation and culture of protoplasts from ponkan and tobacco. Additionally, differential DNA methylation fragments are cloned, sequenced, and subjected to bioinformatics analysis. The results reveal that, for non-regenerable ponkan mesophyll protoplasts, DNA methylation levels increase by 3.98% after isolation and then show a trend of initial decrease followed by an increase during culture. In contrast, for regenerable ponkan callus protoplasts and tobacco mesophyll protoplasts, DNA methylation levels decrease by 1.75% and 2.33%, respectively, after isolation. During culture, the DNA methylation levels of ponkan callus protoplasts first increase and then decrease, while those of tobacco mesophyll protoplasts show an opposite trend of initial decrease followed by an increase. Regarding DNA methylation patterns, ponkan mesophyll protoplasts exhibit primarily hypermethylation changes accompanied by a small amount of gene demethylation, whereas ponkan callus protoplasts are dominated by demethylation changes with some genes undergoing hypermethylation. The methylation exhibits dynamic changes in protoplast isolation regeneration. By recovering, cloning, sequencing, and performing BLASTn alignment analysis on specific methylation modification sites in the ponkan, 18 DNA sequences with high homology are identified which are found to be involved in various biological functions, thereby establishing a foundational basis for genetic editing in protoplasts.

Citrus yellow vein clearing virus infection triggers phloem remobilization of iron- and zinc-nicotianamine in citrus.

Citrus yellow vein clearing virus (CYVCV) is a worldwide and highly destructive disease of citrus, but the mechanisms involved in CYVCV-inhibited plant growth are not well understood. This study examined nutrient levels and their cellular distribution in different organs of healthy and CYVCV-affected citrus (Citrus reticulata 'Kanpei') plants. We found that CYVCV-infected plants exhibit characteristic symptoms, including a significant reduction in iron (Fe) and other elemental nutrients in the shoots. Our data suggest that CYVCV-induced chlorosis in citrus leaf veins is primarily due to iron deficiency, leading to reduced chlorophyll synthesis. Further analysis revealed a marked decrease in iron concentration within the pith and xylem of citrus petioles post-CYVCV infection, contrasting with increased Fe and zinc (Zn) concentrations in the phloem. Moreover, a substantial accumulation of starch granules was observed in the pith, xylem, and phloem vessels of infected plants, with vessel blockage due to starch accumulation reaching up to 81%, thus significantly obstructing Fe transport in the xylem. Additionally, our study detected an upregulation of genes associated with nicotinamide metabolism and Fe and Zn transport following CYVCV infection, leading to increased levels of nicotinamide metabolites. This suggests that CYVCV-infected citrus plants may induce nicotinamide synthesis in response to Fe deficiency stress, facilitating the transport of Fe and Zn in the phloem as nicotinamide-bound complexes. Overall, our findings provide insight into the mechanisms of long-distance Fe and Zn transport in citrus plants in response to CYVCV infection and highlight the role of nutritional management in mitigating the adverse effects of CYVCV, offering potential strategies for cultivating CYVCV-resistant citrus varieties.

Carboxymethyl cellulose based edible nanocomposite coating with tunable functionalities and the application on the preservation of postharvest Satsuma mandarin fruit

This study introduces an innovative carboxymethyl cellulose (CMC)-based edible nanocomposite coating, with two-dimensional layered double hydroxide nanosheets (2D LDH-NSs) and shellac, engineered to address challenges in fruit preservation. The synergistic integration of shellac and LDH-NS into the CMC matrix is strategically designed with tunable functionalities, encompassing wettability, gas barrier, and tensile properties. Our findings reveal that incorporating shellac and LDH-NS significantly improves the coating's wettability on the mandarin fruit surface, thus bolstering its adherence and uniformity, alongside enhancing its water vapor barrier efficacy and influencing the oxygen permeability. The application of this novel edible nanocomposite coating on Satsuma mandarin (Citrus unshiu Marc.) fruits has yielded promising outcomes in prolonging postharvest shelf life while preserving essential quality attributes, including peel surface morphology, weight loss, hardness, color retention, and nutritional values. Our work signifies a significant leap forward for the edible coating technology and bolsters the postharvest preservation of perishable fruits.