Tangor Research Articles

Antimicrobial activity evaluation of combinations of essential oils, thymol and R-limonene against food-borne pathogens and spoilage agents

The application of essential oils has been shown to be an effective and sustainable alternative against the multiplication of spoilage and pathogenic microorganisms in food. The aim of this work was to study the antimicrobial activity effect of Cerrado Rosemary (Baccharis dracunculifolia DC.), Pepper Rosemary (Lippia sidoides Cham.), Mandarin (Citrus nobilis Lour.), Mexican Lime (Citrus aurantifolia Swingle) essential oils, and the thymol and R-limonene compounds against strains of Penicillium expansum, Pichia kudriavzevii, Salmonella Thypimurium and Staphylococcus aureus. The essential oils were characterized in terms of their chemical composition, the Minimum Inhibitory Concentration, and Minimum Bactericidal and Fungicidal Concentration; using the microdilution method in 96-well plates. In addition, effects from mixtures of the essential oils, and the isolated compounds in sub-inhibitory concentrations were performed. The Pepper Rosemary essential oil and thymol, separately, showed the lowest Minimum Inhibitory Concentration values against all the microorganisms evaluated, with the lowest ranging from 0.03 to 1.25 mg. mL−1 for P. expansum and 0.31–1.25 mg. mL−1 for S. Thypimurium. Mandarin and Mexican lime, have an enhanced antimicrobial effect when used in mixture. The R-limonene compound showed a synergistic additive effect when combined with the essential oils, against S. aureus strains only. The application of thymol and Lippia was able to reduce growth by 3 log10 for S. aureus and S. Typhimurium in 24 h. Therefore, the Pepper Rosemary essential oil, applied freely or in combination with the thymol compound, has greater potential for use as an antifungal and bactericidal agent, against the microorganisms evaluated.

Characterization of Bacterial Population Associated with Deterioration of Stored Kinnow Fruits (Citrus nobilis x Citrus deliciosa)

Fresh and spoiled Kinnow fruits were collected from local market in Kharar, Punjab, India to isolate and identify the microbial factors that causes deterioration of stored Kinnow (Citrus reticulata), as well as to study the impact of temperature to fruits at different storage conditions. Several microorganisms, including bacteria and fungus, may thrive in ideal condition present within the fruits. Using the pour plate method, the infected portion of the fruit was utilised to isolate the bacteria by serial dilution. Healthy colonies were selected and sub-cultured. Two types of bacteria have been isolated. Following morphological analysis and biochemical characterization, Staphylococcus spp. and Escherichia coli were determined to be the responsible organism.

Characterization of Citrus × Poncirus Embryo Rescued Hybrids as Rootstock Candidate using Morphological Markers

In generally, there are both of nucellar and zygotic embryos in the citrus seeds after cross breeding. Since genetic variations are very important for success of plant breeding, morphological traits of individuals are evaluated to identify diversity. The present study aimed to characterization of citrus hybrids for new rootstock genotypes based on its morphological characters at seedling stage. A total of 335 putative interspecies hybrids, derived from 3 crosses [Common sour orange (Citrus aurantium L.) × Troyer citrange (Citrus sinensis L. × Poncirus trifoliata L.), Common mandarin (Citrus deliciosa Ten.) × Troyer citrange (Citrus sinensis L. × Poncirus trifoliata L.) and King mandarin (Citrus nobilis L.) × Carrizo citrange (Citrus sinensis L. × Poncirus trifoliata L.)], were observed by their plant morphology. The eight qualitative and five quantitative characteristics of hybrid plants such as seedling growth, leaf and thorniness characteristics were evaluated. The average plant height of the population was found between 70.2 cm and 133.2 cm. The average stem diameter varied between 5.9 mm and 8.0 mm. Hybrid seedlings were separated on the basis of dominant trifoliate leaf marker. There was wide diversity among the accessions with respect to quantitative leaf characters. In terms of leaf division, 268 genotypes have bifoliate and 67 were trifoliate in all combinations, and many intermediate forms were also observed. In addition 66 of the genotypes were thornless while 269 of the genotypes were thorny. The genotype No. 4, has been assessed as triploid, from Common mandarin × Troyer citrange combination, has the longest and dense spines. Morphological markers data were analysed by clustering method to compare similarities of hybrids. The dissimilarity index was observed between 0.004 and 17.318 within three hybridization combinations. The hybrids obtained at 110 days after pollination were more distant relative to each other all hybridization combination.

Implementation of laser-light backscattering imaging for authentication of the geographic origin of Indonesia region citrus

Citrus fruit (Citrus nobilis Lour.) from the Indonesian region is reported to have high economic value due to attractive nutritional, nutraceutical, and sensory attributes. However, authenticating the geographic origins is challenging because of adulteration and similarity in visual appearance. Therefore, this study aimed to develop an effective method based on laser-light backscattering imaging (LLBI) for authentication of the geographic origin of the region citrus. A total of 200 citrus samples were collected from Medan, Malang, Jember, and Banyuwangi regions, which were the four main citrus-producing areas in Indonesia. Approximately three different laser wavelengths, namely 450, 532, and 648 nm were beamed to produce the backscattering image. Furthermore, a combination of the gray-level co-occurrence matrix (GLCM) method and support vector machine (SVM) algorithm was applied to extract texture features and build a classification model, respectively. In this context, three kernel functions, such as linear, radial basis function, and polynomial, were compared in authenticating the geographic origin of citrus. The results showed that the proposed technique achieved 96.667 % accuracy and 3.333 % apparent error for authentication of the geographic origin. The proposed LLBI technique applied a laser wavelength of 450 nm and a polynomial kernel function as the best combination to produce reliable predictive power. This study held valuable implications for advancing sensing technology devices to authenticate geographic origin, specifically citrus fruit.

Preservation effect of sodium alginate-based edible coating enriched with Siam Pontianak tangerine peel oil on chemical and microbiological properties of strawberry during refrigeration storage

Abstract Strawberry is one of the most popular, nutritious, and valuable fruits. However, it has a short shelf life. Preservation by sodium alginate-based edible coating enriched with tangerine peel oil could maintain the physical quality of strawberries during refrigeration storage. However, its effect on chemical and microbiological properties has yet to be reported. This research evaluated the effect of sodium alginate-based edible coating enriched with Siam Pontianak tangerine (Citrus nobilis var. Microcarpa) peel oil at various concentrations (0%, 0.3%, 0.5%, and 0.7%) on strawberries’ chemical and microbiological properties during six days of storage in a refrigerator. The non-coated sample was also prepared as a control. The results showed that the treatments affected the quality of strawberries, including pH, vitamin C, total titratable acidity, and total plate count, except moisture content. The incorporation of 0.5 and 0.7% Siam Pontianak tangerine peel oil into an edible coating based on sodium alginate is a better approach to preserving strawberry quality than other methods. This finding suggests that the Siam Pontianak tangerine peel essential oil can be used as a natural preservative agent to extend the shelf life of strawberries.

A comparative study of gallium doping on electrochemical and optical properties of green synthesized FeO–MgO nanoparticles using Citrus Nobilis

A comparative study of gallium doping on electrochemical and optical properties of green synthesized FeO–MgO nanoparticles using Citrus Nobilis

EMS induced in vitro mutagenesis for solid mutant induction and validation of mutants using morphological and molecular tools in kinnow mandarin (Citrus nobilis × Citrus deliciosa)

EMS induced in vitro mutagenesis for solid mutant induction and validation of mutants using morphological and molecular tools in kinnow mandarin (Citrus nobilis × Citrus deliciosa)

Validity of e-handout diversity bacterial colonies in rhizosphere Citrus nobilis at Karang Bunga Agrotourism Barito Kuala

Digital handouts, or e-handouts, are learning tools students can use to learn more efficiently and flexibly. This study aimed to assess the validity of e-handouts on bacterial diversity in the rhizosphere of Citrus nobilis as Microbiology enrichment material. This research uses the Research and Development (R&D) method with the ADDIE model, which is limited to the development stage. The subjects in the study consisted of validation tests by three validators, namely material experts. As many as two people are lecturers in the Microbiology and Plant Physiology Course of Biology Education FKIP ULM Banjarmasin and one media expert from a lecturer in Educational Technology FKIP ULM Banjarmasin. In the e-handout validation test, the material validator was rated as very valid with a percentage of 86.15%, and the developed media validator showed the e-handout was very valid with a percentage of 100%. It can be concluded that the e-handout of bacterial colony diversity in the rhizosphere of Citrus nobilis meets the category of very valid, and suggestions for further research can be carried out until the product implementation stage. Abstrak. Handout digital, juga dikenal sebagai e-handout, adalah alat pembelajaran yang dapat digunakan siswa untuk belajar agar lebih efisien dan fleksibel. Tujuan dari penelitian ini untuk menilai kevalidan e-handout tentang keragaman bakteri yang ada di rizosfer Citrus nobilis sebagai bahan pengayaan Mikrobiologi. Penelitian ini menggunakan metode Penelitian dan Pengembangan (R&D) dengan model ADDIE yang dibatasi sampai tahap pengembangan (development). Subjek pada penelitian terdiri dari uji validasi oleh 3 orang validator, yakni ahli materi sebanyak 2 orang yang merupakan dosen Pengampu Mata Kuliah Mikrobiologi dan Fisiologi Tumbuhan Pendidikan Biologi FKIP ULM Banjarmasin dan 1 ahli media dari dosen Teknologi Pendidikan FKIP ULM Banjarmasin. Pada uji validasi e-handout oleh validator materi dinilai sangat valid dengan persentase sebesar 86,15%, dan validator media yang dikembangkan menunjukkan e-handout sangat valid dengan persentase 100%. Dapat disimpulkan bahwa e-handout keragaman koloni bakteri pada rizosfer Citrus nobilis memenuhi kategori sangat valid dan saran untuk penelitian selanjutnya bisa dilakukan sampai tahap implementasi produk.

Assessment of Land Quality for Siamese Orange (Citrus nobilis var. microcarpa) Development in Pacitan Regency, Indonesia

Siamese oranges are one of the most widely developed horticultural crops in Indonesia. Arjosari and Ngadirojo are some of the sub-districts that produce Siamese orange in Pacitan Regency. One of the factors that can affect the development of citrus is land quality. This study aims to obtain land quality index data and improvement efforts for developing Siamese orange. Soil samples were taken from 25 land mapping units (LMUs) with 87 sample points. The soil sampling points were determined based on area or sampling density. Data analysis used for soil quality assessment includes correlation, principal component analysis (PCA), minimum data set (MDS), and calculation of climate quality index. The parameters used in this study are bulk density, porosity, moisture content, texture, pH, electrical conductivity (EC), cation exchange capacity (CEC), base saturation, total N, available P, available K, soil organic carbon (SOC), microbial biomass carbon (MBC), evapotranspiration, temperature, and solar radiation. Based on the results of soil quality analysis in the study area, it has a value range of 0.28 to 0.37, including low class, while the climate quality index is 1.39 with moderate class. The land quality index has a very low to low class with a value of 0.39 to 0.51. Intrinsic, extrinsic, and anthropogenic factors can influence soil quality. The study area’s limiting factors for developing Siamese oranges are EC, total N, and available P, which can be improved by making furrow ponds, adding organic fertilizer, using urea fertilizer, and SP36 according to the dosage.

Application of response surface methodology on optimization of textural properties in the development of gelatin-based jelly candy from honey orange (Citrus nobilis) and purple passion fruit (Passiflora edulis Sims)

Jelly candy is a type of confectionery made from a mixture of fruit juices or flavores syrups and gelling agent such as gelatin which produced chewy candy with variety of flavors and shapes. Honey orange and purple passion fruit are both the trademark fruits in North Sumatera. This study examined changes of fruit juice ratio and gelatin concentration toward the gumminess, hardness, chewiness, cohesiveness, springiness and adhesiveness which are textural properties of jelly candy. The test was carried out with the use of texture analyzer. The change of fruit juice ratio and gelatin concentration gives effect to change of gumminess, hardness, chewiness, cohesiveness, springiness and adhesiveness. Optimal fruit juice ratio and gelatin concentration using the response surface methodology (RSM) randomized with central composite design (CCD) occur at ratio of honey orange juice and purple passion fruit of 70 : 30 with a gelatin concentration of 12.923% with the textural properties of gumminess, hardness, chewiness, cohesiveness, springiness and adhesiveness are 508.291 g, 265.736 g, 20.932 mJ, 1.160, 2.696 mm and 0.0000 mJ, respectively.

Biological and molecular characterization of citrus bent leaf viroid

Background and aimCitrus bent leaf viroid (CBLVd) is one of the emerging and widely distributed viroids in citrus-growing areas of the world, including Pakistan. Previously, CBLVd has been reported in Pakistan for the first time in 2009. Therefore, characterization of CBLVd is required to monitor the viroid status in the citrus orchards concerning citrus decline. MethodsBiological and molecular characterization of CBLVd was studied through biological indexing and confirmation through RT-PCR, followed by phylogenetic analysis of selected CBLVd isolates. Among four citrus cultivars viz., Kinnow (Citrus nobilis × Citrus deliciosa), Mosambi (C. sinensis), Futrell's Early (C. reticulata) and Lemon (C. medica) used as indicator plants for two transmission trials viz., graft inoculation and mechanical inoculation. Graft inoculation was more efficient than mechanical inoculation. ResultsSymptoms such as mild mosaic, slight backward leaf bending, and leaf curling were observed after eight months’ post-inoculation. Citrus nobilis × Citrus deliciosa, C. reticulata and C. sinensis were more sensitive to CBLVd as compared to C. medica. Inoculated plants were reconfirmed through RT-PCR amplicons of 233 bp. The phylogenetic tree of submitted sequences showed more than 90% relevance of CBLVd in Pakistan compared to the rest of the world. ConclusionsThere was slight genetic variability, but more than 90% relevance was found among the submitted and already reported CBLVd isolate from Pakistan. Scanty literature is available regarding the biological and molecular studies of CBLVd in Pakistan. Therefore, the transmission and molecular characterization of CBLVd in Pakistan were studied for the first time.

Effect of different coating material and packaging materials on quality and shelf life of Kinnow (Citrus nobilis x Citrus deliciosa) fruit

Effect of different coating material and packaging materials on quality and shelf life of Kinnow (Citrus nobilis x Citrus deliciosa) fruit

Extração e avaliação de atividades antimicrobianas de óleos essenciais de casca de laranja (Citrus nobilis) cultivada no município de Can Tho, Vietnã

ABSTRACT: This study determined the extraction conditions, chemical composition, and antimicrobial activities of the essential oils of Citrus nobilis. The results illustrated that soaking in the 9% (w/v) NaCl solution for 2 h with a sample and solvent ratio of 1:3 (w/v) and a subsequent extraction time of 45 min yielded the highest extraction efficiency, reaching 3.66% (w/w). The main chemical components of the essential oils were limonene (90.42%), β-myrcene (4.7%), and α-pinene (1.22%). The minimum inhibitory concentration (MIC) at the density of 5x104, 5x105, and 5x106 cells/mL of Escherichia coli were 100, 125, and 125 mg/mL, respectively; for Staphylococcus aureus were 75, 100, and 125 mg/mL, respectively; and for Bacillus cereus were 50, 75, and 100 mg/mL, respectively. The minimum bactericidal concentration (MBC) at densities of 5x104, 5x105, 5x106 cells/mL of E. coli were 175, 225, 225 mg/mL, S. aureus were 150, 200, 225 mg/mL, and B. cereus were 125, 175, 200 mg/mL, respectively. The inhibitory activities of Aspergillus flavus of orange essential oils according to the agar dilution method at concentrations of 0.025-0.1%) on the 5th day were 8.84-30.61%.

Mapping the Geospatial Distribution of Citrus Greening Disease in District Layyah, Pakistan

Citrus greening disease is one of the established causes of citrus decline in tropical and subtropical areas of the world, including Pakistan. Citrus greening disease is being recognized based on its characteristic symptoms in the field. Symptomatology and Iodo-starch test are the parameters for rapid disease indexing in the field and laboratory and are also helpful for disease mapping. A study was carried out to record the incidence and severity of citrus greening disease within the area of new citrus plantations of Layyah district, including the tehsils viz., Layyah and Karror. The Layyah tehsil showed an incidence of 18%, while Karror showed an incidence of 5.5%. Among the cultivars, the highest disease incidence was attributed to Kinnow (Citrus nobilis x C. deliciosa) at 33% followed by Mosambi (C. sinensis) at 16% and Feutrall’s early at 5%. The highest disease severity was recorded at Layyah with 22.2%. The lowest was observed at Karror with 13.3%. Among the cultivars, Kinnow showed the highest severity, ranging from 27.22% to 36.6% and the least disease severity was recorded in Feutrall’s early of 8.3% at ± 0.05 level of significance. The present study not only helped establish the relationship between the symptomology and quick indexing of disease through iodo-starch test but also provided information through disease mapping in the new citrus plantation of Layyah district for the first time

Determination of physical properties of siamese oranges (Citrus nobilis var. Microcarpa): sphericity, roundness, volume, and density

Siamese oranges are a member of the tangerines which have the scientific name Citrus nobilis var.Microcarpa. It is called Siamese orange because it comes from Siam (Muangthai). The quality of Siamese oranges is determined by their physical properties. These physical properties include size, weight, volume and diameter. Post-harvest technology for Siamese oranges can be done by grading to obtain quality Siamese oranges according to standards. This research aims to determine the physical properties of Siamese oranges used in the grading process. Determination of sphericity and roundness is measured using a caliper. Determination of volume and density is measured using a beaker. Analysis of research data used a one-way z-test normal distribution to the left. The results of data analysis show that the z-count value of roundness, roundness, volume and density is 1.05; 0.79; 0.55; 0.53 and -ztable of -1.645. This means zcount ≥ -ztable, where the average value of the physical properties of Siamese oranges is greater than or equal to the research object, roundness is 0.92, roundness is 0.93, volume is 87 cm3 and density is 1.02 g/ cm3. Thus, the results of these physical properties can be used as a reference when grading Siamese oranges code size 2.

In Vitro Shoot Culture Growth of Pontianak Orange (Citrus nobilis var. microcarpa) with the Addition of Naphthalene Acetic Acid and 6-Benzyl Amino Purine

Pontianak siam orange (Citrus nobilis var. microcarpa) is an important agricultural commodity unique to Sambas Regency, West Kalimantan. The demand for Pontianak siam oranges has been steadily increasing over the years, yet the production of Pontianak oranges has not been able to meet the domestic demand. The limited availability of superior seedlings is one of the reasons for this situation. Therefore, efforts are needed to fulfill the demand for Pontianak siam oranges by producing a large quantity of superior seedlings in a short period. One of the strategies that can be employed is in vitro propagation. This research aims to observe the growth of Pontianak Siamese orange shoot explants after administration of NAA (Naphthalene Acetic Acid) and BAP (6-Benzyl Amino Purine). This research was conducted from January to June 2023 at the Tissue Culture Laboratory of the Department of Biology, Faculty of Mathematics and Natural Sciences, Tanjungpura University. The study employed a Completely Randomized Design (CRD) with two treatment factors namely NAA concentrations with 4 levels (0; 0.25; 0.5; 0.75 mg/L), and BAP concentrations with 5 levels (0; 0.5; 1; 1.5; 2 mg/L). Parameters observed were the emergence time of shoot, shoot number, height of shoot, and the number of leaves. The results showed that single NAA, single BAP, and combination treatment of NAA and BAP significantly affected all growth parameters. Treatment with the addition of 0.25 mg/L NAA and 1 mg/L BAP (A1B2) was the treatment with the fastest shoot emergence time (2.80 days after planting), the largest number of shoots (2.60 shoots)the tallest shoots (1.50 cm), , and the greatest number of leaves (2.60 leaves).

Structural Characterization, Antioxidant, Antidiabetic and Antimicrobial Activities of Citrus Limettarisso, Citrus Nobilis X Citrus Deliciosa and Citrus Maxima

Background: The pharmacological properties of citrus fruits have long been recognized in traditional medicine, with recent scientific studies corroborating their potential as sources of natural bioactive compounds. Citrus limettarisso, Citrus nobilis x Citrus deliciosa, and Citrus maxima, in particular, have garnered attention for their antioxidant, antidiabetic, and antimicrobial properties. Prior research has highlighted these species' capabilities, with various studies reporting on their significant health benefits. Objective: This study aims to evaluate and compare the antioxidant, antidiabetic, and antimicrobial activities of essential oils extracted from the peels of Citrus limettarisso, Citrus nobilis x Citrus deliciosa, and Citrus maxima, thereby contributing to the understanding of their potential therapeutic applications. Methods: Essential oils were extracted from the peels of the three citrus species using hydro distillation. The antioxidant activity was assessed through Total Phenolic Content (TPC), Total Flavonoid Content (TFC), and DPPH Radical Scavenging Assay. Antiglycation potential and alpha-amylase inhibition were evaluated for antidiabetic properties, while antimicrobial activity was determined using the Agar Well Diffusion Method. Results: Citrus limettarisso showed the highest TPC (301.4474 ± 2.930402 mg GAE/100g) and significant antioxidant activity (68.26347% DPPH scavenging). Citrus maxima exhibited a high TFC (143.8727 ± 5.454545 mg CE/100g) but lower TPC (115.8333 ± 3.553444 mg GAE/100g). Citrus nobilis x Citrus deliciosa demonstrated considerable TPC (244.1667 ± 5.862774 mg GAE/100g) and TFC (50.17576 ± 0.457566 mg CE/100g). Antiglycation and alpha-amylase inhibition assays revealed Citrus limettarisso as the most potent antidiabetic agent with the highest inhibition percentages. All three species showed significant antimicrobial activity. Conclusion: The study confirms the substantial pharmacological potential of Citrus limettarisso, Citrus nobilis x Citrus deliciosa, and Citrus maxima, particularly in terms of their antioxidant and antidiabetic properties. Citrus limettarisso emerged as the most potent in most assays, underscoring its potential for therapeutic use. These findings support the use of these citrus species as natural sources of bioactive compounds for health and medical applications. It carries special importance for public health advancements.

BIOLOGY AND MORPHOMETRICS OF PAPILIO DEMOLEUS L. (CITRUS BUTTERFLY) ON NURSERY PLANTS OF KINNOW UNDER LABORATORY CONDITIONS AT TALWANDI SABO BATHINDA, PUNJAB

The present study was carried out at Guru Kashi University in 2019?2020 on the biology and morphometrics of Papilio demoleus L. (the Citrus butterfly) on nursery plants of Kinnow. The Citrus butterfly goes through first to fifth instars with a span of 2.3, 2.6, 2.63, 3.57, and 5.03 days, respectively. The total larval period was 16.13 ? 0.278 days, and the pupal stage lasted between 8 and 9 days. Compared to female butterflies, male butterflies had shorter lifespans. Each female produced 96.87 ? 1.534 eggs with an oviposition period of about 4?5 days. The incubation period of the butterfly lasted between 2 and 5 days, with a total lifespan of 26?32 days. The smooth, cream-yellow colored eggs were 0.96?1.16 mm in diameter, averaging 1.009 ? 0.223 mm. First, second, third, fourth, and fifth instars? average larval lengths were 4.475 ? 0.231, 8.755 ? 0.143, 13.61 ? 0.211, 24.728 ? 0.685, and 38.655 ? 0.509 mm, respectively. The pupae were primarily green and varied from 27.75 to 37.5 mm. Body length measurements for males and females were 28.02 ? 0.499 and 29.43 ? 0.465 mm, respectively, with wingspans around 91.925 ? 2.152 and 99.8 ? 1.783 mm.. KEYWORDS :Biology, Citrus delicosa, Citrus nobilis, Morphometry, Papilio demoleus

Defluoridation of Water by Biowaste Material – A Study of Adsorption Kinetics and Isotherms

Human beings experience adversative effects due to the large fluoride concentrations present in potable water. Because of the low cost and simple operation, the extensively acknowledged process is adsorption. The objective of this study is to investigate the performance of some of the prepared carbons from bio-waste materials viz., Citrus limon, Citrus nobilis, Pithecellobium dulce, and Bombax malabaricum sheaths in defluoridation. Initial concentration, particle size, agitation time, adsorbent dose, and pH were the different parameters chosen to study their effect on adsorption. Studied the adsorption kinetics. Further suitability to adsorption isotherms was reviewed.

First report of Colletotrichum siamense causing Fruit Drop in Kinnow mandarin (Citrus nobilis x Citrus deliciosa) in Punjab, India

Kinnow, a hybrid developed by crossing two cultivars of mandarin i.e. King (Citrus nobilis) x Willow leaf (Citrus deliciosa) accounts for its high economic productivity and possess high processing quality along with great aromatic flavour. Kinnow mandarin cultivation occupies 4,73,000 ha of land in India with an annual production of 62,65,000 MT (Anonymous, 2021) and Punjab is the leading Kinnow producing state in India. Fruit drop is a major problem in Kinnow mandarin causing serious damage in the quality and yield of the fruit. During 2020–21, the symptoms of fruit drop were observed in Kinnow orchards of Punjab as; drying of twigs from the tip downwards, brown discoloured circular areas on stem-end of the fruit, rotting, and dropping of the fruit. To identify the casual agent, the infected fruit tissue bits (2 mm) was surface sterilized with 1% mercuric chloride solution for 30–40 s and given three washings of distilled water and placed on whatman filter paper-1 to soak all the excessive moisture. The bits was placed on Potato Dextrose Agar (PDA) plates and incubated at 25 ± 1 °C. The colony colour ranged from creamy white to light gray with orange conidial mass in the centre. Based on various morphological characteristics i.e., conidial shape, size, spore production, presence or absence of fruiting body and size of fruiting body the fungus was identified as Colletotrichum siamense. For molecular confirmation ITS region, actin (ACT) and beta-tubulin2 (TUB2) genes were amplified using primers ITS-6/ITS-4, ACT-512F/ACT-783R and T1/Bt2b, respectively. PCR amplicons for three loci (ITS, ACT and TUB2) were sequenced and sequences were deposited in GenBank as accession numbers OQ857285, OQ983464 and OQ983465 for isolate no. C-4 and OQ888798, OQ983466 and OQ983467 for isolate no. C-19, respectively. The BLAST analysis and multigene phylogenetic analysis showed that the isolates collected in present study were phylogenetically similar to the C. siamense. Thus, based on morphological, phylogenetic analysis and pathogenicity assays, the causal agent was identified as Colletotrichum siamense. This is the first report of C. siamense causing fruit drop of kinnow mandarin in Punjab, India.