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... Additionally, various natural and anthropogenic disturbances in NEI have led to the reduction of wild populations, and many species are currently under the threat of extinction, warranting immediate study. The number of Citrus species recognized based on morphological traits ranges from three to four (Linnaeus 1753; Hooker 1875), or 145 to 162 (Tanaka 1954(Tanaka , 1969(Tanaka , 1977. Two of the commonly used taxonomical treatments by Swingle and Reece (1967) and Tanaka (1977) recognize 16 and 162 species, respectively. ...
... The number of Citrus species recognized based on morphological traits ranges from three to four (Linnaeus 1753; Hooker 1875), or 145 to 162 (Tanaka 1954(Tanaka , 1969(Tanaka , 1977. Two of the commonly used taxonomical treatments by Swingle and Reece (1967) and Tanaka (1977) recognize 16 and 162 species, respectively. In a phylogenetic study using 146 morphological and biochemical characters, Barrett and Rhodes (1976) recognized only three true species within cultivated Citrus, namely, C. medica L. (citron), C. reticulata Blanco (mandarin), and C. grandis (L.) Osbeck (pomelo). ...
... Leaf samples of 24 Citrus species (112 accessions) were collected from Assam, Meghalaya, Mizoram, and Arunachal Pradesh of NEI. The identification of collected samples was based on the comparison of morphological characters with those of herbarium specimens and following taxonomic monographs on Citrus (Swingle 1943;Tanaka 1954Tanaka , 1977Bhattacharya and Dutta 1956;Swingle and Reece 1967;Mabberley 2004). Samples collected for the present study included all major Citrus species (sweet and sour orange, mandarin, citron, pomelo, and grapefruit) and four species of the subgenus Papeda (Table 9.1). ...
With the increase in human population, over exploitation of bioresources and climate change, there is an ever-growing threat to biological resources and biodiversity. Numerous species of plants and animals are under constant pressure of being extinct due to habitat loss and degradation. Loss of biodiversity would not only be disruptive to the delicate functioning of ecosystems but also incur huge losses economically affecting food security and public health among others. Understanding the inter-dependencies between life forms and their microbiomes is one of the many facets of conservation strategies that can aid in sustainable utilisation of bioresources. This chapter highlights the importance of metagenomics in elucidating roles of microbial (bacterial and fungal) communities whether it be in the gut of an animal, the rhizosphere of a plant or soil in a tropical forest. Due to the unculturability of most microbial species, metagenomics proves to be an effective approach in identifying the microbial wealth as well as their role in the ecological niches. In metagenomics, the total DNA of the collected sample is extracted followed by amplification of certain conserved genes, for example, 16S rDNA in bacteria and ITS regions in fungi. Knowledge of these phylogenetic profiles can be integrated with other existing data to assess host physiology and metabolism, which are known indicators of threat to biodiversity.
... The classification criteria are mainly based on morphological characteristics. There are two principal systems of Citrus taxonomy: Swingle and Reece's (1967) system [9], and Tanaka's (1977) system [10]. These two authors presented two different concepts of classification. ...
... The classification criteria are mainly based on morphological characteristics. There are two principal systems of Citrus taxonomy: Swingle and Reece's (1967) system [9], and Tanaka's (1977) system [10]. These two authors presented two different concepts of classification. ...
... Thus, the main differences between Swingle and Tanaka classification concern the recognition of Citrus hybrids, cultivars, bud spots, and variant taxa as true botanical species. Tanaka (1977) considered them as absolute botanical species; on the other hand, Swingle and Reece did not accept them as true taxonomic species. ...
Citrus species are one of the world's popular fruit crops, cultivated all over the world for their economic and nutritional values. Citrus, like other fruits and vegetables, are an important source of several antioxidant molecules (polyphenols, ascorbic acid, and carotenoids) that can inhibit the harmful effects of free radicals on the human body; due to their functional values and health-promoting properties, Citrus species are considered valuable fruits not only in agri-food industry , but also in pharmaceutical industry. Flavonoids are among the major constituents of poly-phenols found in different parts of Citrus fruits (skin, peels, seed, pulp membrane, and juice). Fla-vonoids have different biological properties (antiviral, antifungal, and antibacterial activities). Several studies have also shown the health-related properties of Citrus flavonoids, especially antioxi-dant, anticancer, anti-inflammation, anti-aging, and cardiovascular protection activities. In the present review, attempts are made to discuss the current trends of research on flavonoids in different Citrus species.
... There are approximately 160 genera belonging to the family Rutaceae, and Citrus is the most important genus from an economic perspective. There are several systems of Citrus classification which vary widely; the Swingle and Reece (1967) and Tanaka (1977) classification systems are accepted widely, which differentiate based on the number of recognized species [3,4]. Barrett and Rhodes (1967) [5] reported that the true species of Citrus are: Citron (C. ...
... There are approximately 160 genera belonging to the family Rutaceae, and Citrus is the most important genus from an economic perspective. There are several systems of Citrus classification which vary widely; the Swingle and Reece (1967) and Tanaka (1977) classification systems are accepted widely, which differentiate based on the number of recognized species [3,4]. Barrett and Rhodes (1967) [5] reported that the true species of Citrus are: Citron (C. ...
Citrus, belonging to the Rutaceae family, is a commercial fruit worldwide, and it is mainly recognized for its nutritional, anti-oxidant, and significant medicinal properties. Citruses are a group of multifaceted fruit crops with a rich traditional knowledge, deeply rooted in ethnic culture, and the fruits have been considered to be health-protecting and health-promoting food supplements since ancient times. The presence of secondary metabolites and their bioactivities has led to the development of new alternative drugs in recent years. Diverse secondary metabolites such as flavonoids, alkaloids, carotenoids, phenolic acids, and essential oils and their high bioactive properties have imparted great value to human health based on their anti-oxidative, anti-inflammatory, anti-cancer, cardiovascular protective, and neuroprotective effects. The indigenous Citrus species of India—mainly Northeast India—have distinctive and valuable genetic traits, such as resistance to biotic and abiotic stress, distinctive aroma, flavor, etc. Hence, these species are considered to be repertoires of valuable genes for molecular breeding aimed at quality improvement. There is a need for awareness and understanding among the citrus-producing countries of the exploitation of biodiversity and the conservation of Citrus for sustainable development and bioprospecting. The current review presents a holistic view of Citrus biodiversity from a global perspective, including phytochemical constituents and health benefits. Advanced biotechnological and genomic approaches for Citrus trait improvement have also been discussed to highlight their relevance in Citrus improvement.
... The Rutaceae are a large, widely distributed family of trees and other woody plants comprising about 150 genera and some 180 species. 1 The genus Citrus has been variously described as consisting of from 1 to 162 species. 2,3 The most widely accepted taxonomic systems today are those of Swingle (1946) and Tanaka (1977) who recognized 16 and 162 species, respectively. Relationships among taxa are complicated by several factors such as a high frequency of bud mutation, a long history of cultivation, and wide crosscompatibility. ...
... The Rutaceae are a large, widely distributed family of trees and other woody plants comprising about 150 genera and some 180 species. 1 The genus Citrus has been variously described as consisting of from 1 to 162 species. 2,3 The most widely accepted taxonomic systems today are those of Swingle (1946) and Tanaka (1977) who recognized 16 and 162 species, respectively. Relationships among taxa are complicated by several factors such as a high frequency of bud mutation, a long history of cultivation, and wide crosscompatibility. ...
Lemon, lime, orange, grapefruit, bergamot, mandarin and bitter orange species which have major characteristic specialities of Rutaceae family, have antimicrobial activities on pathogene microorganisms. Probiotic microorganisms have valuable effects on human body and inhibition of probiotics causes many diseases. In this present study, it was aimed to determine indicate probiotic resistance against natural antimicrobial agents (as essential oils) compare to pathogenes in previous studies. Analysis of essential oils (Eos) from were analyzed by GC-FID and GC/MS, analysis of Eos antimicrobial and antifungal activity from were analyzed by Microdilution test. Limonene (%95.29) and Linalool (%34.94) were found as major compounds of EOs respectively. All essential oils have antimicrobial activities on probiotic microorganisms.
... The taxonomy of the citrus fruits is complicated by hybridity and apomixis with many stable hybrids lines being accorded species status. Though many taxonomists classified Citrus, Swingle's andReece, 1967 andTanaka's, 1977 classifications are widely followed. While, Swingle's recognized 16 species, Tanaka recognized 162 species. ...
Efficient identification and characterization of the accessions is highly required for the conservation and sustainable use of plant genetic resources. Since the entire plant kingdom cannot be covered under sequencing projects, molecular markers and their correlation to phenotypes provide us with requisite landmarks for classification and genetic variation. Various molecular techniques such as Random Amplified Polymorphic DNA (RAPD), Amplified Fragment Length Polymorphism (AFLP), Sequence-Related Amplified Polymorphism (SRAP), Inter Simple Sequence Repeats (ISSR), Simple Sequence Repeats (SSR) and Single Nucleotide Polymorphisms (SNPs) have recently been used for fruit plant characterization. The construction of genetic maps using RFLP was the first reported molecular marker technique in the detection of DNA polymorphism (Botstein et al., 1980). The projects of genome sequencing for several fruit crops such as citrus, apple, peach and strawberry has good results in molecular characterization. Attempts were made to classify citrus using molecular markers like RFLP and RAPD (Federici et al., 1998; Baig et al., 2009). AFLP markers have the advantages over other molecular markers like, SSR, RFLP and RAPD.
... The process by which mandarin citrus were disseminated to Southeast Asia, especially to Indonesia, still needs to be clarified. According to Swingle (1943) system, siam citrus or King mandarin was classified as Citrus reticulata, while Tanaka (1977) system classified it as Citrus nobilis. Molecular analysis using RAPD and SCAR markers reported by Nicolosi et al. (2000) clustered C. nobilis in mandarin cluster together with all mandarin (C. ...
Citrus is one of the prominent horticultural crops that is highly consumed by people around the world. Being located near the equator, Indonesia has several mandarin citrus genotypes, including siam and keprok citrus, which remain poorly characterized. Hence, assessing of their genetic diversity will help us identify genotypes that possess important traits suitable for breeding programs. The objective of this study were to analyze the genetic diversity of Indonesia’s local mandarin citrus genotypes using Simple Sequence Repeat (SSR) and Start Codon Targeted (SCoT) markers and compare the robustness of those markers in genetic diversity analysis. Thirty-seven mandarin genotypes consisting of 7 siam cultivars, 28 keprok cultivars, and 2 cultivars derived from their hybridization, were subjected to genetic diversity analysis using 20 SSR and SCoT markers. The number of alleles detected by SCoT markers was higher than by SSR markers. SCoT markers accounted for 119 alleles, while SSR markers accounted for 99 alleles. The number of alleles at each locus detected by SCoT and SSR markers varied from 4 to 9 and 2 to 7, respectively. In addition, 15 SCoT and 13 SSR markers with Polymorphic Information Content (PIC) values greater than 0.5 were identified, which indicated their potential as highly informative markers in citrus breeding programs. The phylogenetic tree and principal coordinate analysis (PCoA) plot constructed from SSR and SCoT markers revealed differentiation between the siam and keprok cultivars. The analysis of molecular variance (AMOVA) results indicated that there was greater genetic variation within populations than among populations, thus suggesting extensive cross-pollination in the citrus genotypes studied. The population structure, as indicated by the highest delta K value of K = 2 in SSR markers and K = 3 in SCoT markers, showed evidence of gene flow occurred among citrus populations. The findings have implication for future citrus breeding.
... With 162 species, the genus citrus is one of the most significant taxonomic components of the Rutaceae family. It is abundant in edible fruits like oranges, lemons, tangerines, mandarins, and limes [3,4]. In terms of economic, social, and cultural value, citrus are among the main fruit crops traded internationally. ...
Citrus cultivars have various temperature needs for development and output at different times from flowering to harvesting, making climate one of the numerous factors that affect citrus’ productivity and quality. In this study, the yield and heat unit requirements for several commercial citrus species over several seasons from 2010/2011 to 2021/2022 in Egypt were investigated. For this investigation, the time of flowering and the time of fruit harvesting were recorded. However, the required heat units from flowering to fruit harvesting were calculated based on daily records of air temperature, taking into account that all results below zero (negative results) are not used and all maximum air temperatures above 35.0 °C (≥35.1) are changed to 35.0 °C. In addition, the base air temperature of 13.0 °C was utilized for determining the required heat units. The results showed that in the experimental area, the overall mean of minimum air temperature, maximum air temperature, air relative humidity, and precipitation during the experimental periods had values of 15.2 °C, 28.70 °C, 59.3%, and 0.3 mm/day, respectively. Moreover, the lowest number of days required from flowering to fruit harvesting was observed to be 290.0 days for Fremont mandarin. Furthermore, the highest number of days required from flowering to fruit harvesting was observed to be 482 and 440 days, respectively, for Bearss Seedless lime and Valencia orange. Our study has highlighted a notable diversity among the investigated citrus cultivars, particularly highlighting specific cultivars that possess high yield. The cultivar that shows the greatest yield over the investigated seasons of the study was Valencia orange with 147.6 kg/tree. Moreover, the average values of the heat unit requirements for Washington Navel orange, Valencia orange, Murcott mandarin, Fremont mandarin, and Bearss Seedless lime were 3112.7, 3628.3, 3221.9, 3027.6, and 4398.4 °C day, respectively. This is the first report regarding the heat unit’s determination for several citrus cultivars grown in Egypt, and we expect this research will provide a new awareness in accepting and discovering novel locations where citrus cultivars can be positively developed in Egypt. It will also prove to be a source of basic information for the development of the citrus crop model.
... Existem duas classificações do gênero Citrus, a de Swingle (1948), que compreende 16 espécies, e a de Tanaka (1977), que estabeleceu um sistema mais moderno, incluindo 162 espécies, pertencentes à divisão Magnoliophyta, subdivisão Magnoliophytina, classe Magnoliopsida, subclasse Rosidae, ordem Sapindales, subordem Geranineae, família Rutaceae, subfamília Aurantioideae, tribo Citreae e subtribo Citrineae (Passos et al., 2005). Por produzirem frutos semelhantes à laranja ou ao sinensis) e pomelos (C. ...
A região amazônica possui uma vasta área territorial, um exemplo de biodiversidade para o mundo, com sol e chuva durante o ano todo e um grande potencial para conciliar a produção de alimentos em bases sustentáveis e o meio ambiente. Para um ótimo desenvolvimento e produção dos cultivos amazônicos, é primordial respeitar as exigências nutricionais específicas para cada espécie. Ao se deparar com solos de baixa fertilidade, deve-se identificar com precisão os nutrientes deficientes para que seja realizada a fertilização com precisão suficiente para atender à demanda nutricional de cada espécie cultivada, de forma que se atinja a ótima produtividade dos cultivos.
Temos notado uma grande dificuldade para obter informações sobre a nutrição mineral de cultivos amazônicos; esse conhecimento está pulverizado em artigos científicos, capítulos de livros, revistas técnicas, anais de eventos, trabalhos de graduação, dissertações e teses. Nesse cenário, foi oportuno reunir tais informações em uma só obra inédita, Nutrição de cultivos amazônicos.
Além de ser uma obra de fácil leitura e muito esclarecedora, com abordagem aprofundada na nutrição de cada planta, constata-se uma grande amplitude de espécies, reunindo os principais cultivos amazônicos: açaizeiro, cacaueiro, coqueiro, dendezeiro, feijão-caupi, jambu, laranjeira, muricizeiro e pimenta-de-cheiro. Nutrição de cultivos amazônicos é fonte primária para adquirir o conhecimento necessário ao manejo da nutrição desses cultivos, ajudando técnicos, pesquisadores, produtores e estudantes a maximizar o crescimento e a produtividade das culturas e minimizar problemas de doenças e pragas comuns em plantas com desordens nutricionais. Portanto, a acertada abrangência dos temas explorados cobrirá importante lacuna das informações técnico-científicas para o desenvolvimento agrícola sustentável da região amazônica.
... Traditionally, the taxonomic classification of citrus relied heavily on geographical and morphological data. Swingle and Reece (1967) and Tanaka (1977) presented two prominent taxonomic categorization systems for citrus, with Swingle's method recognizing 16 species in the Citrus genus and Tanaka's system identifying 162 species, highlighting their divergent approaches. According to Scora (1975) and Barrett and Rhodes (1976), the Citrus subgenus comprises only three genuine 'basic' citrus varieties: lemon (C. ...
The complexity of citrus phylogeny and taxonomy, influenced by polyembryony, genetic diversity, and extended generation cycles, necessitates assessing genetic relationships for improved production and disease resilience. DNA polymorphism markers are pivotal in genotyping and resolving phenotypic varietal ambiguities through accurate and objective genetic relatedness and distinctiveness assessments. In this study, 27 accessions of kagzi and ornamental lime were evaluated at morphological (based on IPGRI citrus descriptor), biochemical, and molecular levels using DNA-based markers, namely, random amplified polymorphic DNA (RAPD), start codon targeted (SCoT) polymorphism, and simple sequence repeats (SSR). Morphological analysis unveiled significant variation in leaf lamina attachment, shape, margins, fruit characteristics, and texture across all parameters. Biochemical research noted minimal differences, with total soluble solids (TSS) ranging from 5.7° to 8.0° Brix and titratable acidity (TA) from 0.36 to 0.50%. Notably, ornamental lime accessions exhibited higher TSS:TA ratios of 16.00. Molecular markers (RAPD, SCoT, and SSR) corroborated these findings, yielding 115, 74, and 64 amplicons, respectively, with polymorphic percentages varying from 33.33 to 100%. Polymorphic information content ranged from 0.20 to 0.90 for RAPD, 0.41 to 0.99 for SCoT, and 0.07 to 0.67 for SSR markers. Analysis of molecular variance (AMOVA) substantiated significant genetic differences among the kagzi and ornamental lime accessions (RAPD PhiPT = 0.267, SCoT PhiPT = 0.351, SSR PhiPT = 0.107). Furthermore, STRUCTURE software 2.3.4 revealed a ΔK value of two (K = 2), indicating two distinct genetic pools within the accessions, possibly attributable to bud mutations generating varying morphological traits within the same plant. Molecular marker-based germplasm characterization can mitigate confusion linked to morphological characteristics and multiple cultivar registrations.
... The Tanaka system recognizes 162 species (Tanaka 1977), while the classification described by Swingle (1943) displays a spectacular reduction of species compared with Tanaka's one (Carbonell-Caballero et al. 2015). Recently Mabberley (2004) proposed to include three main species and four hybrids for commercial fruits of Citrus and this classification represents a good foundation to which robust phylogenomic data can now be applied (Ollitrault et al. 2020). ...
... It has a long history in agriculture more to 400 years [2]. Citrus Citrus sp is native to the family of saprophytes Rutaceae and consists of (1 -162 ) species [3]. Citrus trees are planted all over the world, in both tropical and subtropical climates, as well as in the transition zones between the two [4]. ...
On Dhi-Qar University’s Department of Horticulture and Garden Engineering used their Saran-covered plastic greenhouse during the 2022 growing season for an experiment. The experiment started on 15 \ 1\ 2022. The experiment was designed as a working experiment according to the design of complete randomized block Design (R.C.B.D, the experiment included two factors, the main factor was the stages of salinity of irrigation water (1, 2, 4) decimens. M ⁻¹ and the second agent is Tocopherol (0 a–, 150, 300 ) mg. L ⁻¹ is produced by the Indian company HIMEDIA with three repeaters. Important findings from the study included the fact that as saline levels in irrigation water increased, most of the attributes under investigation suffered considerable declines, especially the Level (4 decimens M ⁻¹ ), which gave the lowest rates in the qualities (plant height rate, stem diameter rate, branch number rate, leaf number rate, leaf area rate, soft weight rate of the vegetative total, dry weight rate of the vegetative total), as the measurements reached (60.24 CM. Plant ⁻¹ , 5.51 mm Plant ⁻¹ , 4.46 branches. Plant ⁻¹ , 75.11 leaves. Plant ⁻¹ , 965.00 cm2. Plant ⁻¹ , 45.09 G. Plant- ¹ , 15.45 G. Plant ⁻¹ ) respectively, as to add a – Tocopherol sprayed on the vegetative total has a positive moral effect and the treatment exceeded (300) mg. L ⁻¹ gave the highest measurements in the following characteristics (plant height rate, stem diameter rate, branch number rate, leaf number rate, leaf area rate, soft weight rate of the vegetative total, dry weight rate of the vegetative total), reaching (78.17 CM. Plant ⁻¹ , 7.74 mm Plant ⁻¹ , 7.58 branches. Plant ⁻¹ , 88.04 leaves. Plant ⁻¹ , 1661.33 cm2. Plant ⁻¹ , 55.06 G. Plant ⁻¹ , 19.44 G. Plant ⁻¹ ) respectively.
... The genus Citrus was first subdivided into the subgenera Papeda and Eucitrus by Swingle in 1967(Swingle, 1967. However, Tanaka divided the genus Citrus into the subgenera Archicitrus and Metacitrus (Tanaka, 1977), while Zeng Mian, a Chinese expert on Citrus, classified the genus Citrus into the subgenera Papeda, Citron, Cephalocitrus, Aurantium, and Sinocitrus (Zeng, 1962). In addition, Scora, Barrett, and Rhodes believed that C. medica, C. maxima, and C. reticulata are the key species of the genus Citrus based on the essential oil composition of Citrus leaves. ...
Citrus species are fruit trees with great economic value worldwide and have been domesticated and cultivated for several years. Although numerous phylogenetic taxonomy studies have been conducted since the establishment of the genus Citrus, the determination of phylogenetic relationships of Citrus species and the discrimination of Citrus subgenera face some challenges due to species hybridization, polyembryony, and asexual reproduction. In this study, the complete chloroplast genomes of 16 Citrus species were de novo assembled, then several unique characters were identified. For example, infA and rpl22 gene losses occurred in Citrus species; the trnQ-UUG gene may have played a significant role in the evolution of Citrus species; the rpoC1 gene in chloroplast genomes of Citrus species was under positive selection; and several highly variable loci (trnK-UUU–trnQ-UUG, atpF–atpH, trnG-GCC–trnfM-CAU, accD–psaI, petD–rpoA, and rpl32–trnL-UAG) were found in the chloroplast genomes of the Citrus species. These variable loci could serve as potential markers for phylogenetic studies. The genus Citrus was subdivided into seven subgenera based on phylogenetic analyses of the complete chloroplast genomes of Citrus species: Poncirus, Fortunella, Papeda, Citron, Cephalocitrus, Aurantium, and Sinocitrus. This study may help with the identification, taxonomy, use, and evolution of Citrus species.
... Mandarin was reported as the most phenotypically and genotypically heterogenous (Moore, 2001) and was proposed as one of the 'three ancestral species' in cultivated Citrus (Barett and Rhodes, 1976). Swingle and Reece (1967) classified all the mandarins as one species, whereas Tanaka (1977) classified them into 36 species. Barkley et al. (2006) reported that the mandarins were the most polymorphic among the ancestral species. ...
Nepal has very low Citrus fruit production compared to other countries, which is due to lack of elite varieties and cultivars having desirable traits. Therefore, breeding of elite cultivars is crucial to address ever increasing market demand of citrus fruits in Nepal. Genetic diversity characterization of Citrus germplasm at molecular level is important and crucial step for their utilization in breeding and conservation. In the present investigation, we aimed to utilize 12 SSR markers to characterize genetic diversity of forty-five Citrus accessions of Citrus collected from National Citrus Research Program (NCRP), Dhankuta and Kathmandu valley. A total of 60
putative alleles were amplified at 12 SSR loci with an average of five alleles per locus. PIC value ranged from 0.497 with primer TAA 27 to 0.802 with primer TAA 41 with an average value of 0.662. Probability of identity (PI) ranged from 0.075 to 0.383 with an average value of 0.143. Observed Heterozygosity (Ho) ranged from
0.460 to 0.794 and Expected Heterozygosity (He) ranged from 0.460 to 0.794. Shannon’s Information Index (I) ranged from 0.677 to 1.678. Principal co-ordinate analysis (PCO) revealed the first principal co-ordinate axis accounting 20.35% and second axis accounting 11.43% of the total variation. UPGMA clustering using Jaccard’s similarity coefficient grouped 45 accessions into four clusters. The information generated from this investigation will be useful for National Agriculture Genetic Resources Center (Gene bank) of Nepal and other relevant Citrus researchers and breeders for their conservation, Molecular Breeding-based Research & Development and their sustainable future utilization
... The genus Citrus, belonging to the Rutaceae family, is represented by about 160 genera with 16 (Swingle System; [1]) to 162 (Tanaka System; [2]) species that are distributed throughout tropical and subtropical regions worldwide [3]. To date, Citrus has been much appreciated as one of the most important commercial fruit crops, with an estimated global production of lemons and limes above 9 million tons during the period of 2021-2022 [4]. ...
This study evaluates the applicability of enantioselective gas chromatography (eGC) and enantioselective comprehensive two-dimensional gas chromatography (eGC×GC) coupled with flame ionization detection for the stereospecific analysis of designated chiral monoterpenes within essential oils distilled from the leaves of Citrus hystrix (CH), C. limon (CL), C. pyriformis (CP), and C. microcarpa (CM). A cryogen-free solid-state modulator with a combination of enantioselective first-dimension and polar second-dimension column arrangements was used to resolve potential interferences in Citrus spp. leaf oils that can complicate the accurate determination of enantiomeric compositions. Interestingly, considerable variations were observed for the enantiomeric fractions (EFs) of the chiral terpenes. (+)-limonene was identified as the predominant enantiomer (60.3–98.9%) in all Citrus oils, (+)-linalool was the major enantiomer in CM (95.9%), (−)-terpenin-4-ol was the major isomer in CM (66.4%) and CP (61.1%), (−)-α-pinene was the dominant antipode in CL (55.5%) and CM (92.1%). CH contained (−)-citronellal (100%) as the pure enantiomer, while CL and CP have lower proportions (9.0–34.6%), and citronellal is absent in CM. The obtained enantiomeric compositions were compared and discussed with results from eGC using the same enantioselective column. To our knowledge, this work encapsulates the first report that details the EFs of these chiral monoterpenes in Citrus spp. leaf oil.
... Consumers appreciate the ease of peeling, the balance of sweetness and acidity, its juice content and the lack of pips. The flesh is very juicy, very aromatic and slightly acidic Montaigne et al. [23][24][25][26][27][28][29][30][31][32][33][34][35]. ...
Citrus fruits are among the most popular crops worldwide. Its species are cultivated all over the world not only for their economic values and nutritional properties but also for their valuable genetic material in breeding process. In Tunisia, Citrus industry occupies also a paramount importance in the agricultural sector being one of the strategic products. However, little is known about the pomological diversity of Tunisian sweet oranges specifically minor cultivars whose description is mainly given through folk tales. Thus, several investigations were undertaken aiming to collect and to characterize the orange local germplasm. These allowed the identification of 25 different local cultivars including minor ones listed for the first time. Ten quantitative and 19 qualitative traits were measured. The experimental results revealed an overall diversity of the local citrus germplasm based on traits as fruit's dimensions shape and base shape, texture of surface, pulp firmness and vesicle thickness.
... The genus Citrus belongs to the Rutaceae family, which is comprised of about 160 genera and approximately 162 species (according to the Tanaka classification system), which are distributed throughout the world [1,2]. Apart from culinary uses, Citrus spp. ...
The essential oil derived from Citrus plants has long been used for medicinal purposes, due to its broad spectrum of therapeutic characteristics. To date, approximately 162 Citrus species have been identified, and many investigational studies have been conducted to explore the pharmacological potential of Citrus spp. oils. This study investigated the volatile constituents of essential oil distilled from the leaves of C. hystrix, C. limon, C. pyriformis, and C. microcarpa, using gas chromatography–quadrupole mass spectrometry. A total of 80 secondary compounds were tentatively identified, representing 84.88–97.99% of the total ion count and mainly comprising monoterpene (5.20–76.15%) and sesquiterpene (1.36–27.14%) hydrocarbons, oxygenated monoterpenes (3.91–89.52%) and sesquiterpenes (0.21–38.87%), and other minor chemical classes (0.10–0.52%). In particular, 27 compounds (1.19–39.06%) were detected across all Citrus species. Principal component analysis of the identified phytoconstituents and their relative quantities enabled differentiation of the Citrus leaf oils according to their species, with the loading variables contributing to these metabolic differences being identified. The Citrus leaf oils were tested for their antioxidant and antiproliferative activities using 2,2-diphenyl-1-picryl-hydrazylhydrate (DPPH) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. The results indicated that C. limon displayed the highest DPPH radical scavenging ability (IC50 value of 29.14 ± 1.97 mg/mL), while C. hystrix exhibited the lowest activity (IC50 value of 279.03 ± 10.37 mg/mL). On the other hand, all the Citrus oils exhibit potent antiproliferative activities against the HeLa cervical cancer cell line, with IC50 values of 11.66 μg/mL (C. limon), 20.41 μg/mL (C. microcarpa), 25.91 μg/mL (C. hystrix), and 87.17 μg/mL (C. pyriformis).
... It belongs to the family Rutaceae and sub-family Aurantioideae. The genus citrus includes 162 species and is extensively grown in the tropical and sub-tropical parts of the world (Tanaka, 1977). The majority of the species of citrus are originated in tropical and sub-tropical parts of South East Asia, mainly India and China and in the area among these two countries. ...
Scarcity of water is pervasive on earth across all plant grow ping realm. Water is the major constraint for horticulture production in Rajasthan as well as other parts of the country. At the time of peak summer, no drop of water remains available for crop production. Day by day ground water resources are getting deep due to excessive use of aquifer without much concern for its replenishment. During the peak summer no drop of water remains available for horticulture and agriculture in the region. There is a need of water saving technique. The field experiment was conducted deploying 10 treatments in RBD with four replications covering 160 plants in all during two successive years commencing from March, 2019 to February, 2020 and March, 2020 to February, 2021 at the Instructional Farm, Department of Fruit Science, College of Horticulture and Forestry, Jhalawar, Rajasthan. The experiment revealed that among various irrigation schedule treatments, application of treatment I 1 (100% ETc) was found better in improvement of the soil microbial population in soil (Bacteria 18.17 × 10 6 CFU/g soil and Fungi 12.62 × 10 4 CFU/g soil). As regard to individual effect of fertigation, better influence on microbial population (Bacteria 19.33 × 10 6 CFU/g soil and Fungi 13.78 × 10 4 CFU/g soil) was found under treatment F 3 (60% RDF). Among the interaction of irrigation schedule and fertigation levels, soil microbial population (Bacteria 20.75 × 10 6 CFU/g soil and Fungi 15.20 × 10 4 CFU/g soil at 0-15cm depth of soil) had significantly better improvement in treatment I 1 F 3 (Irrigation Scheduling at 100 % ETc + Fertigation 60 % RDF).
... The genus Citrus belongs to the Rutaceae family is economically important and is known throughout the world for its juice and pulp. According to Tanaka (1977), this genus includes 162 species and is grown in tropical and subtropical parts of the world. In India, there are 30 Citrus species (Singh and Chadha 1993) of which at least nine species are available throughout India, while, the northeastern Himalayan region contains 23 species, 1 subspecies, 7 probable natural hybrids, and 68 varieties of citrus (Bhattacharya and Dutta, 1956;Sharma et al., 2004). ...
Khasi Mandarin fruit (Citrus reticulata Blanco) is one of the most important commercial fruit crops of the northeastern hill region of India. The fruit is unique in taste, aroma, and flavour, thus considered as one of the best mandarins. The fruits have several uses including food industries, pharmaceutical industries, etc with the stored house of bioactive compounds for health benefits. Given these, good orchard management practices are very essential for higher yield and quality production of Khasi mandarin fruits. This will indirectly improve the economics of the orchardist.
... Rutaceae and sub-family Aurantioideae. The genus citrus includes 162 species and is extensively grown in the tropical and sub-tropical parts of the world [1]. The majority of the species of citrus originated in tropical and sub-tropical parts of South East Asia, mainly India and China and in the area among these two countries. ...
The field experiment entitled "Effect of Irrigation Schedule and Fertigation Level on Nutrient Uptake and Soil Fertility of Mandarin (Citrus reticulate Blanco.) cv. Nagpur Mandarin" was conducted by deploying 10 treatments in RBD with four replication covering 160 plants in all during two successive years commencing from March 2019 to February 2021 at the Instructional Farm, Department of Fruit Science, College of Horticulture and Forestry, Jhalawar, Rajasthan. The experiment revealed that among various irrigation schedule treatments, the application of treatment I1 (100% ETc) was observed significantly superior over other treatments concerning leaf parameters in which the increase in leaf NPK content particularly N: 2.53%, P: 0.23%, K: 1.72% and soil NPK particularly N: 319.13 kg ha-1 , P:24.58 kg ha-1 , K: 290.92 kg ha-1 at 0-15cm depth were observed under this treatment I1 (100% ETc). As regard to individual effect of fertigation, maximum leaf NPK content (N: 2.56% P: 0.23%, K: 1.75%) and soil NPK particularly N: 322.28 kg ha-1 , P: 26.10 kg ha-1 , K: 295.25 kg ha-1 at 0-15cm depth were observed under the treatment F1 (100% RDF). Among the interaction of irrigation schedule and fertigation levels, leaf and soil parameters were observed significantly superior in treatment I1F1 (Irrigation Scheduling at 100 % ETc + Fertigation 100 % RDF) while treatment I2F1 (Irrigation Scheduling at 80 % ETc + Fertigation 100 % RDF) was registered followed by with it in most of the leaf parameters and soil parameters was observed at par with treatment I2F1 studied. This work is licensed under a Creative Commons Attribution Non-Commercial 4.0 International License.
... Rutaceae and sub-family Aurantioideae. The genus citrus includes 162 species and is extensively grown in the tropical and sub-tropical parts of the world [1]. The majority of the species of citrus originated in tropical and sub-tropical parts of South East Asia, mainly India and China and in the area among these two countries. ...
The field experiment entitled "Effect of Irrigation Schedule and Fertigation Level on Nutrient Uptake and Soil Fertility of Mandarin (Citrus reticulate Blanco.) cv. Nagpur Mandarin" was conducted by deploying 10 treatments in RBD with four replication covering 160 plants in all during two successive years commencing from March 2019 to February 2021 at the Instructional Farm, Department of Fruit Science, College of Horticulture and Forestry, Jhalawar, Rajasthan. The experiment revealed that among various irrigation schedule treatments, the application of treatment I1 (100% ETc) was observed significantly superior over other treatments concerning leaf parameters in which the increase in leaf NPK content particularly N: 2.53%, P: 0.23%, K: 1.72% and soil NPK particularly N: 319.13 kg ha-1 , P:24.58 kg ha-1 , K: 290.92 kg ha-1 at 0-15cm depth were observed under this treatment I1 (100% ETc). As regard to individual effect of fertigation, maximum leaf NPK content (N: 2.56% P: 0.23%, K: 1.75%) and soil NPK particularly N: 322.28 kg ha-1 , P: 26.10 kg ha-1 , K: 295.25 kg ha-1 at 0-15cm depth were observed under the treatment F1 (100% RDF). Among the interaction of irrigation schedule and fertigation levels, leaf and soil parameters were observed significantly superior in treatment I1F1 (Irrigation Scheduling at 100 % ETc + Fertigation 100 % RDF) while treatment I2F1 (Irrigation Scheduling at 80 % ETc + Fertigation 100 % RDF) was registered followed by with it in most of the leaf parameters and soil parameters was observed at par with treatment I2F1 studied. This work is licensed under a Creative Commons Attribution Non-Commercial 4.0 International License.
... This led to major controversy on systematics of species within the Citrus subgenus. Two dissimilar classifications schemes have been developed and adopted; the Swingle system that recognizes 16 species (Swingle and Reece, 1967) and the Tanaka taxonomy that superfluously splits and identifies 162 species in the genus (Tanaka, 1977). However, advanced studies based on biochemical and morphological traits, suggests that there are only three 'true' species, i.e. citron (C. ...
The present study was carried out on five sweet orange Cvs., namely White Khalili, Red Khalili, Succari, Navel and Mazizi to throw Their some light on genetic relationships and fingerprinting Profiles via 5 IRAP-PCR Primers. These primers characterized by their higher to moderate degrees of successful in amplification potentiality for reproducible, polymorphic fragments, specific markers and Co-dominated, as well as their discriminatory power. Obtained data regarding the genetic analysis of the 5 orange Cvs. based on the 5 IRAP primers detected that 59 fragments were amplified from which 37 bands were polymorphic with 63%. In addition, 29 bands of these poly morphic ones were positive unique and considered as specific markers. So there 5 sweet orange Cvs didn't give identical DNA fingerprint. The number of total and polymorphic amplified fragments across the 5 orange Cvs by each IRAP Primer showed a considerable variation. Since, the F10&B6 was the superior (21 total and 18 polymorphic fragments), with the highest Polymorphism % (86). In addition, the number of Positive unique DNA fragments (specific markers) generated by the F10&B6 primer varied greatly from one cultivar to another. Herein Navel Orange cv. occurred the highest number followed by Red Khalili, both (White Khalili & Succary) and finally Mazizi i.e, exhibited 5,4,3,3 and 2 specific markers, respectively.
... Over the last century, many classification systems for citrus taxonomy have been proposed based on geographical and morphological data. Among these, two important but distinct systems by Swingle and Reece (1967) and Tanaka (1977) have gained immense popularity and were widely accepted. Their classification systems were based on the species number they recognized, while Swingle reported only 16 species in the genus Citrus; on the other hand, 162 Citrus species were identified by Tanaka. ...
The highly-demanded commercial citrus fruits of family Rutaceae arose primarily through sexual hybridization between the four ancestral taxa generating a range of nothospecies. The diversity of phenotypic traits in these cultivable groups was mainly due to somatic mutations fixed either by apomixis present in Citrus species or grafting for clonal propagation, leaving behind very scanty evidence to study the process of citrus domestication apart from its genealogy. Moreover, sexual compatibility between Citrus and its related genera is another broad area of controversy leading to a continuous reformulation of citrus taxonomy and phylogeny. Although advanced genomic studies to clarify the phylogenetic relationships of citrus are in progress, a detailed overview of citrus taxonomy, diversity, origin and domestication would enhance our knowledge not only to get an evolutionary framework of citrus phylogeny but also to unravel the history of citrus domestication. Therefore, the review has been presented comprehensively with recent studies emphasizing the identification of specific reproductive, sensory and morphological markers selected as traits during the course of domestication. Hence, studies on identifying genes related to polyembryony, self-incompatibility (SI) and anthocyanin production between wild and cultivated citrus have been discussed to provide new insights on citrus apomixis, SI and citric acid reduction. Further, the correlation of pummelo introgression with fruit size and palatability in cultivable mandarins has also been focused on understanding mandarin domestication.
... M andarin-type citrus comprise a heterogeneous group of east Asian citrus with small and typically easily peelable fruit 1,2 . Because of their consumer-friendly attributes, mandarins have seen the greatest percentage increase in global citrus production 3 .The phenotypic and genomic diversity of mandarin types in the Nanling region of southern China has driven speculations that mandarins first arose and were domesticated in this region 4 . ...
The origin and dispersal of cultivated and wild mandarin and related citrus are poorly understood. Here, comparative genome analysis of 69 new east Asian genomes and other mainland Asian citrus reveals a previously unrecognized wild sexual species native to the Ryukyu Islands: C. ryukyuensis sp. nov. The taxonomic complexity of east Asian mandarins then collapses to a satisfying simplicity, accounting for tachibana, shiikuwasha, and other traditional Ryukyuan mandarin types as homoploid hybrid species formed by combining C. ryukyuensis with various mainland mandarins. These hybrid species reproduce clonally by apomictic seed, a trait shared with oranges, grapefruits, lemons and many cultivated mandarins. We trace the origin of apomixis alleles in citrus to mangshanyeju wild mandarins, which played a central role in citrus domestication via adaptive wild introgression. Our results provide a coherent biogeographic framework for understanding the diversity and domestication of mandarin-type citrus through speciation, admixture, and rapid diffusion of apomictic reproduction. To explore the nature of wild and cultivated mandarins, the authors carry out genomic analysis of diverse east Asian citrus. The discovery of a wild species Citrus ryukyuensis native to the Ryukyu islands and a new population of wild mainland Asian mandarin explains the origin and diversity of mandarins and their ability to reproduce apomictically.
... The most widely known taxonomic systems for citrus are Swingle [16] and Tanaka [17], who documented 16 and 162 species. Sweet orange, mandarin, pummelo, grapefruit, lemon, lime, and various hybrids are among the most commonly grown and economically important fruit tree crops in the genus citrus [18]. ...
Background
Releasing the draft genome of sweet orange provides useful information on genetic structure and molecular marker association with heritable breeding traits in citrus species and their structures. Last decades, microsatellite and retrotransposons are well known as a significant diverse component of the structural evolution. They represented the most potent elements for assessing sustainable utilization of the complicated classification in citrus breeding. Our study was performed to verify the structure analysis and the parentage genetic diversity among the Egyptian citrus rootstocks and the related species.
Results
Here, the performance of 26 SSR and 14 LTR-IRAP in addition to 20 LTR-REMAP markers have been used to conduct the discriminating power and the status of the genetic structure analysis among twenty specimens of citrus genotypes. As a result, the three markers approach exhibited a remarkable variation among the tested genotypes. Overall, the three markers have different discrimination power; the co-dominant SSR markers can differentiate within the group level only in addition to the species level of sour orange, while the dominant markers LTR-IRAP had the ability to discriminate among the group level in addition to species level and the origin of acids. Similarly, LTR-REMAP is suitable for classifying the group level and species level for mandarins as well the origin of Egyptian acids; probably due to it is integration of SSR and LTR-IRAP techniques. Structure and PCoA results of LTR-REMAP marker in strong support for the group structure of citrus species have been divided into four sets: acids, grapefruit/pummelo, mandarin/orange, and sour orange.
Conclusion
Our findings of the genetic structure analysis support the monophyletic nature of the citrus species; are able to provide unambiguous identification and disposition of true species and related hybrids like lemon, lime, citron, sour orange, grapefruit, mandarin, sweet orange, pummelo, and fortunella; and resulted in their placement in individual or overlap groups. The outcomes of these results will offer helpful and potential information for breeding programs and conservation approaches as a key stage toward identifying the interspecific admixture and the inferred structure origins of Egyptian citrus rootstock and acid cultivars.
... ex. Tan) also is considered to be a unique and distinct sub-group of mandarins (Tanaka, 1977). Recently, mandarin King (Citrus nobilis -Citrus deliciosa) has been considered a hybrid Tangor, a cross between mandarin (Citrus reticolata) and sweet oranges (Citrus reshni). ...
The objective of this study was to comparison of volatile compounds (VCs) in the green and yellow-orange stage peels of two mandarin ('King' and 'Tangerina') varieties in Turkey. The VCs were analyzed using solid phase micro extraction (SPME) and gas chromatography-mass spectrometry (GC-MS). A total of 92 VCs were identified in mandarin peels analyzed. The number of volatile compounds was greater in yellow peel than green one. There were seventeen VCs (α-pinene, β-pinene, β-myrcene, α-terpinene, limonene, β-thujene, hexanal, γ-terpinene, p-cymene, octanal, decanal, linalool, octanol, α-terpineol, β-selinene, carvone, thymol) common to all mandarin peels. Among these volatile compounds limonene was found in the greatest level representing 68.74-82.03% of all compounds identified in peel. The other major VCs found in mandarin peel were α-pinene (2.45-5.01%), β-pinene (0.07-1.96%), β-myrcene (5.21-6.96%), γ-terpinene (0.32-10.40%) and linalool (1.46-2.24%). VCs α-pinene, β-pinene, α-terpinene, γ-terpinene and p-cymene were higher in cultivar 'Tangerine' than those in 'King'. There was a significant difference between yellow and green peels, namely it was observed that the yellow peels contained more α-terpinene, limolene, decanol, linalool, octanol, carvol but less in β-myrcene and hexanol, when compared with the green peels. VCs β-ocimene, α-copene, germacrene D, isopulegol and β-cubebene were identified in cultivar 'King' only whereas E-2-octenal and lavandulyl acetate were present in 'Tangerina' only.
... There are two major taxonomic systems, namely, Swingle's 10 species (Swingle, 1967) and Tanaka's 162 species (Tanaka, 1977). In most studies, citrus is categorized as one of the three Compared with wild citrus, the cultivars exhibit decreased fruit acidity, secondary metabolite levels (such as bitterness compounds), and tolerance to biotic or abiotic stresses but increased fruit production and taste, which mainly depends on the sugar/acid ratio. ...
Citrus has been originated from South-East Asia, and it becomes one of the most important fruit crops worldwide. Citrus has a long and obscure history of domestication due to clonal propagation, long-life cycle, wide-sexual compatibility, and complex genetic background. With the availability of genomic information from both wild and cultivated citrus, the domestication and underlying traits or genes are becoming clear. This review outlines the features of genomic information on wild and cultivated species. We propose that reduction of citric acid is a critical trait for citrus domestication. The genetic model representing the change of domestication may be associated with regulatory complex known as WD-repeat-MYB-bHLH-WRKY (WMBW) related to vacuolar acidification and anthocyanins accumulation. The reduction or loss in anthocyanins may be due to hitchhiking effect of fruit acidity selection when mutation occurs on the common regulator of these two pathways in some domesticated types. Moreover, we have summarized the domestication traits and candidate genes for breeding purpose. This review represents a comprehensive summary of the genes controlling key traits of interests such as acidity, metabolism, and disease resistance. This review sheds light on recent advances in early flowering by transgenic studies and provides new perspective for fast breeding in citrus. Our review lays a foundation for future research on fruit acidity, flavor, and disease resistance in citrus.
... Species within the genus Citrus are highly economic and medicinal plants distributed all over the world (Swingle and Reece, 1967). Several taxonomists have classified various kinds of Citrus species into groups and given them valid names (Roxburgh, 1832;Brandis, 1874;Marcovitch, 1926;Swingle, 1943;Swingle and Reece, 1967;Hodgson, 1965and Tanaka, 1936and 1977. Swingle's system appears to be the most useable all over the world (Nicolosi, 2007). ...
The present investigation aims to study the pollen morphology and ultra-structure of pollen grain characteristics for nine Citrus species and three related genera cultivated in Egypt. The pollen grains were photographed by using both light (LM) and scanning electron microscopy (SEM). Twelve qualitative and quantitative pollen morphological characters were used to differentiate among the studied taxa. Statistical analysis of palynological data indicated that the pollen size, shape, colpi length, apertures number and type, ora size, amb shape, mesocolpium diameter and exine ornamentation were the most distinguished characters in the circumscription of the studied taxa and were of taxonomic value. But the characters of P/E, ora shape and exine thickness were of less taxonomic value among the closely related taxa of Citrus, Fortunella margarita, X Citrofortunella floridana and Poncirus trifoliata.
Kuroshima-mikan (synonym: Shimamikan) (Citrus sp.) is a local citrus grown on islands in Kagoshima Prefecture, Japan, located in temperate and subtropical areas: Nagashima, Koshikijima, Kuroshima, Tanegashima, Yakushima, Amami Oshima, Kakeromajima, and Tokunoshima. In general, all six Kuroshima-mikan accessions collected on different islands showed similar fruit characteristics. Although the fruit characteristics of Kuroshima-mikan and Kishu-mikan ‘Sakurajima-komikan’ (C. kinokuni) were similar, differences were observed in the flavor, titratable acidity, and embryony. The embrony of the former was polyembryony and that of the latter was monoembryony. In the six Kuroshima-mikan accessions, the genotype combinations of 16 cleaved amplified polymorphic sequence (CAPS) markers were identical to each other. Kuroshima-mikan was distinguished from all control accessions and was closely related to the Chinese mandarin Sunki (C. sunki). The genetic differences between Kuroshima-mikan and the Chinese mandarin Kishu-mikan ‘Sakurajima-komikan’ were greater than those between Kuroshima-mikan and the Indian mandarin Cleopatra (C. reshni), the Japanese mandarin ‘Ogimi-kuganii’ (C. depressa), and Tachibana (C. tachibana). Kuroshima-mikan was distant from the sweet and sour orange, citron, and pummelo. The results of the CAPS analysis ruled out a parent-offspring relationship between Kuroshima-mikan and ‘Sakurajima-komikan’.
Mosambi belonging to the family Rutaceae is a sweet lime variation best cultivated in India, China, southern Japan, Vietnam, Malaysia, Indonesia and Thailand. In India, Mosambi is extremely popular and often produces fruit in 5–7 years. It contains significant amounts of total polyphenols, flavonoids, and other biocompounds with antioxidant characteristics, including vitamin C, minerals, and water-soluble vitamins. This fruit is progressively gaining popularity around the world due to sweet taste of its juice. Many researchers have looked at the extraction, depectinization, pretreatment and final clarity of preprocessed juice. Mosambi has a numerous health benefits, including aiding digestion and contributing in the treatment of scurvy, diabetes, urinary disorders, and skin problems. Apart from this, it also possesses antioxidant, anti-diarrheal, antimicrobial, antiviral, anticancer, anti-inflammatory, hypoglycemic, hypocholesterolemic, antithrombotic, antimicrobial, antihypertensive and diuretic. Mosambi is a high-fiber, low-glycemic-index fruit. The by-products derived from mosambi wastes provide a source of nutraceuticals, which the food, cosmetics, and pharmaceutical industries can use to make low-cost nutritional dietary supplements. This chapter summarized the detailed description of antioxidant components, their characterization, health benefits and nutritional significance of Mosambi with respect to post harvest technologies, its processing, valuable food products and comprehensive utilization of waste in the value added byproducts.
Tangerine or Citrus reticulata is a small oblate, thin-skinned, bright orange, easy-to-peel type of mandarin indigenous to China and Southeast Asia. Tangerine cultivation slowly spread westwards along trade routes as far as the Mediterraneanwhere, in the 1800s, acquired the name tangerine due to the export of this sweet mandarin from the port of Tangiers in Morocco. Nowadays, tangerine production is distributed in more than 140 countries. However, the vast majority of crops are grown in the northern hemisphere in subtropical regions, namely southern Europe, southern United States, and Southeast Asia, with the major producers being China (the largest, with 27 million metric tons (MMT)), European Union, Turkey, United States of Americaand Japan. Currently, tangerine production plays a crucial role in the agri-food industry, with global production being expected to increase by 2.0 MMT by 2021/22, reaching a groundbreaking record of 37.2 MMT.
Although synonymously used, tangerines and mandarins are not necessarily the same, with the latter encompassing tangerines, clementines, and satsumas. The phytotomy of tangerines consists of an exocarp which entails the epidermis and flavedo (containing oil sacks that produce aromatic oils), the albedo (a sponge-like layer that is a source of flavanones), and the vascular bundles. Segments containing the juice sacs and seeds, with septa running along these segments converging onto the central axis of the tangerine, comprise the endocarp.
Tangerine chemical composition is dependent on maturity level, storage, horticultural, and climate conditions, all of which impact the chemical profile of the fruit. Nonetheless, tangerines possess low amounts of proteins and lipids, with carbohydrates (namely, sucrose, glucose, and fructose) being the most prevalent macronutrient. The albedo is rich in dietary fibers composed of cellulose, lignin, and pectin, with the latter being recognized as a valued gelling agent and cholesterol (low-density lipoprotein; LDL) lowering agent. Concerning organic acids, citric is by far the most predominant in tangerines, although trace amounts of malic acid may also be present. Tangerines also comprise a vast array of secondary metabolites, namely, essential oils, flavonoids, phenol acids, alkaloids, limonoids, and carotenoids, among others. Each of these groups of compounds presents a notable biological activity of considerable therapeutic importance to human health and well-being, with flavonoids (namely hesperidin, the most abundant flavonoid in tangerine peel) possessing potent antioxidant, anticarcinogenic and anti-inflammatory properties, as well as neuroprotective effects. Moreover, tangerine bioactive potential has been documented concerning antidiabetic, antiproliferative, antihypertensive, antiatherogenic, antiviral and antimicrobial properties, as well as skin hydrolipidic balance improvement, gut microbiota modulation and cardiomyopathy prevention.
Owing to increasing awareness of healthy eating habits by the average consumer, citrus fruits are regaining more and more a prime role in the daily diets, either being consumed fresh, in the form of juices, or other processed products. Although 70% of all produced tangerines are allocated to be consumed fresh, roughly 30% of all tangerines are subjected to some form of processing. This processing will undoubtedly lead to the formation of waste residues of either solid (peels and seeds), semi-solid (pulp), or liquid nature (wash waters and other effluents). The solid and semi-solid waste residues are mainly composed of the remains of the endocarp and exocarp (seeds, fibers, membranes, and vesicles).
Conventionally, waste management methods for citrus waste englobe composting, incineration, direct discharge into wells, lakes, or other bodies of water. Although incineration may be used for energy production and composting is a valuable end-product, these disposal methods do not harness the full potential of these added-value byproducts. Consequently, in recent years there has been significant development of new processing methods for the total exploitation of the various tangerine waste products. These waste residues are rich in enzymes, carbohydrates, lipids, dietary fibers, organic acids, amino acids, minerals, essential oils, vitamins, and flavonoids. All of those compounds are of utmost interest to the pharmaceutical, cosmetic, and food industries. Nonetheless, in order to be available for the mentioned purposes, those compounds need to be extracted. In this sense, distinct technologies may be applied to obtain the highest yield and purity. The most conventionally used methodology is solvent extraction, which includes the well-recognized “Soxhlet”, together with emerging technologies, namely, supercritical and pressurized fluid extractions (SFE and PFE, respectively). There are also methodologies associating physical stimuli with posterior, or concomitant, use of solvents. Hence, these techniques are often classified as pre-treatments and not as extraction methods per se. This consideration may be applied to microwave and ultrasound-assisted extractions (MAE and UAE, respectively). Other technologies comprise enzyme-assisted extraction (EAE), high hydrostatic pressure (HHP), and pulsed electric field (PEF), among others. In this sense, besides being utilized to extract compounds from unprocessed tangerine, these methodologies/technologies may also be applied to convert waste residues originated in tangerine processing into added-value products.
Consequently, harnessing the various citrus components will undoubtedly contribute to a reduction in the carbon footprint posed by tangerine orchard waste which, in turn, aligns with the thirteenth sustainable development goal aimed at reducing the carbon footprint of food industries.
Tangerine has been exploited towards the formulation of novel food products, namely, marmalades, low-calorie antioxidant and probiotic wort-based beverages, spray-dried tangerine powder-based juices, and extruded snacks. Moreover, waste residues have demonstrated a notable potential for the development of novel products, namely, food preservatives and stabilizers, edible films, supplements, titanium dioxide nanocrystals, carbon quantum dots, bioadsorbents of heavy metals, bio-fertilizers, biogas, bioethanol, and biohydrogen.
The orange subfamily (Aurantioideae) contains several Citrus species cultivated worldwide, such as sweet orange and lemon. The origin of Citrus species has long been debated and less is known about the Aurantioideae. Here, we compiled the genome sequences of 314 accessions, de novo assembled the genomes of 12 species and constructed a graph-based pangenome for Aurantioideae. Our analysis indicates that the ancient Indian Plate is the ancestral area for Citrus-related genera and that South Central China is the primary center of origin of the Citrus genus. We found substantial variations in the sequence and expression of the PH4 gene in Citrus relative to Citrus-related genera. Gene editing and biochemical experiments demonstrate a central role for PH4 in the accumulation of citric acid in citrus fruits. This study provides insights into the origin and evolution of the orange subfamily and a regulatory mechanism underpinning the evolution of fruit taste.
‘Miyagawa-wase’ mandarin (Citrus. unshiu Marc. cv. Miyagawa-wase) is one of the most widely cultivated citrus varieties in Korea. Previously, we used γ-irradiation to develop new citrus varieties by mutation breeding, a useful tool for increasing genetic diversity in a short time. One of the new citrus varieties we generated, Jedae-unshiu, produces uniquely shaped fruit with vertical troughs on the flavedo. Although comparative analyses of genome-wide variation and transcriptomics have been reported for seedless or color-change citrus variants, little is known regarding genetic variants linked to morphological variation in citrus fruits. In this study, genome-wide single nucleotide polymorphisms (SNPs) and insertion/deletion (InDel) variants were identified in Jedae-unshiu by whole-genome re-sequencing and subjected to functional annotation by gene ontology (GO) analysis. The results show that InDel-containing genes are more highly represented in the GO database than SNP-containing genes. In addition, we compared Jedae-unshiu and wild-type control transcriptomes to identify candidate genetic determinants of the unique fruit phenotype of Jedae-unshiu. A total of 641 unique, differentially expressed genes (DEGs) were identified in Jedae-unshiu relative to wild-type control, including 388 up-regulated and 253 down-regulated genes. The DEGs were mapped to GO terms and subjected to Kyoto Encyclopedia of Genes and Genomes pathway analysis to identify DEGs involved in cellular processes potentially linked to the unique phenotype of Jedae-unshiu fruit. The expression of 10 DEGs (5 up- and 5 down-regulated) was quantified by reverse transcriptase-polymerase chain reaction (RT-PCR). Our findings provide insight into putative genetic determinants of fruit morphology in citrus.
Different chemical attributes, measured via total soluble solids (TSS), acidity, vitamin C (VitC), total sugars (Tsugar), and reducing sugars (Rsugar), were determined for three groups of citrus fruits (i.e., orange, mandarin, and acid); each group contains two cultivars. Artificial neural network (ANN) and multiple linear regression (MLR) models were developed for TSS, acidity, VitC, Tsugar, and Rsugar from fresh citrus fruits by applying different independent variables, namely the dimensions of the fruits (length (FL) and diameter (FD)), fruit weight (FW), yield/tree, and soil electrical conductivity (EC). The results of ANN application showed that a feed-forward backpropagation network type with four input neurons (Yield/tree, FW, FL, and FD) and eight neurons in one hidden layer provided successful modeling efficiencies for TSS, acidity, VitC, Tsugar, and Rsugar. The effect of the EC variable was not significant. The hyperbolic tangent of both the hidden layer and the output layer of the developed ANN model was chosen as the activation function. Based on statistical criteria, the ANN developed in this study performed better than the MLR model in
predicting the chemical attributes of fresh citrus fruits. The root mean square error of TSS, acidity, VitC, Tsugar, and Rsugar ranged from 0.064 to 0.453 and 0.068 to 0.634, respectively, for the ANN model, and 0.568 to 4.768 and 0.550 to 4.830, respectively, for the MLR model using training and testing datasets. In addition, the relative errors obtained through the ANN approach provided high model predictability and feasibility. In chemical attribute modeling, the FD and FL variables exhibited high contribution ratios, resulting in a reliable predictive model. The developed ANN model generally showed a good level of accuracy when estimating the chemical attributes of fresh citrus fruit.
Citrus depressa Hayata is the native and widespread citrus species in Taiwan. The notable character is that C. depressa has a distinct aroma different from local citrus. The ex situ germplasm of scions from different collection regions has variant leaf shapes and different odor characteristics. Establishing volatile biomarkers for classifying the local C. depressa is beneficial to commercial development. Volatile organic compounds (VOCs) of fresh leaves from seven C. depressa accessions which were collected from different locations in Taiwan were extracted by headspace solid-phase microextraction and analyzed by GC-MS. The volatile compositions from each season showed the diversity, and linalool, of which the average relative content is 52.7%, was the most volatile component in any season. The other main VOCs of leaves of C. depressa were γ-terpinene, limonene, β-ocimene, and α-terpineol. The result of linear discriminant analysis by VOC markers shows that there are two main different types which are (1) accessions from the central and the east of Taiwan and (2) accessions which are closer to C. depressa in Okinawa, Japan. Five major VOC-related synthase genes were selected and the gene expression was used to classify the varieties. The clustering result is the same with VOC-based discrimination. Our results reveal leaf volatile profiling is capable of being the discrimination markers, and the possibility for constructing molecular markers is directly related to characteristics from secondary metabolites phenotyping.
Sequence-related amplified polymorphism (SRAP) markers were used to detect molecular marker polymorphisms among five parents and four crosses of citrus and their relatives in Aurantioidea. Four SRAP primer combinations produced a total of 160 polymorphic fragments with an average of 40 per primer combination and the an-average polymorphism information content (PIC) of 0.86. The unweighted pair group method arithmetic average (UPGMA) analysis demonstrated that the accessions had a similarity range from 0.35 in the cross between Lemon and Clementine to 0.43 in the Grapefruit parent with a mean of 0.37. The dendrogram separated the parents and the resulted crosses of Citrus species into two main sub-clusters with a similarity value of 0.37. Only one member of the first sub-cluster which is Clementine or the parent of all the resulted crosses. In the second main sub-cluster, Only one member of the first sub-sub-cluster which is Grapefruit or the parent of one cross. The second sub-sub-cluster has consisted of one parent separated alone (Succari parent) and another sub-cluster. This sub-cluster is formed from the sub-sub-cluster including the parent Cleopatra mandarin and the resulting from cross Cleopatra mandarin x Clementine. The last sub-cluster has consisted of one group containing the parent Lemon and the resulted cross Lemon x Clementine. The other group consisted of two crosses; Grapefruit x Clementine and Succari x Clementine.
Citrus is an economically important fruit crop growing worldwide, with enormous health benefits. However, conventional citrus breeding has been hindered by a variety of genetic factors, thereby becoming obsolete and insufficient. Citrus research mostly focused on botanical, taxonomic, and cytogenetics issues. Nowadays the knowledge base has strengthened with the plausible outcomes of commercially successful varietal releases. Unfortunately; this has been gradual with only a few success stories among citrus rootstocks and even fewer among scion cultivars. Recent advancements in genetics, molecular biology, biotechnology, and omics (genomics, transcriptomics, proteomics, and metabolomics) have expedited citrus breeding and genetics research. Linkage mapping, genetic diversity, phylogenetic relationships, mutation breeding, mapping, and the international citrus genome sequencing initiatives along with functional analysis have been comprehensively summarized in this review. While providing information on future avenues, this review provides novel mechanistic compiled up-to-date information based on the past and recent progress, facilitating their broader applications to accelerate citrus breeding.
Northeast India is home to natural and domestic populations of many Citrus L. (Rutaceae) species, suggesting this area is a centre of origin for the genus Citrus, which includes widely cultivated commercial fruit plants such as orange, lemon, and lime. To gain insights into the evolutionary history of Citrus species in the region, we reconstructed the phylogeny of 24 species of Citrus using nucleotide sequences of three chloroplast (trnL-trnF, trnS-trnG, and rps16) and one nuclear (ITS2) genomic region. Phylogenetic relationships inferred through maximum parsimony, maximum likelihood, and Bayesian analyses grouped the 24 morphologically distinct Citrus species into five phylogenetically defined groups. C. indica (Indian wild orange) and C. medica (Citron), both native to eastern Himalayan region of northeast India, clustered together and formed a basal clade, suggesting northeast India may be the ancestral region of Citrus. C. assamensis was a sister taxon to the remaining three Citrus clades, and we found evidence that morphologically based Citrus groups – including acid, papeda, and pomelo – were polyphyletic. Our results provide genetic clarification for Citrus evolution, a group that had a previously unclear in its phylogenetic history.Keywords
Citrus
Chloroplast and nuclear DNANortheast IndiaPhylogeny
Citrus is the most widely produced fruit group in the world. Approximately 3 million tons of citrus fruit are produced in Turkey. With total export of one million tons, our country is ranking as the 4 th Citrus exporter in the world and ranking as the 2 nd among the Mediterranean countries. Mandarin production is 874.832 tons in Turkey and 8,72% of total mandarin production was Clementine mandarin in 2012. From different citrus ecological regions top selection of qualified individuals at "Citrus Budwood Selection-Certification and Variety Development Project" 7 promising types were selected from the Clementine mandarin types and BATEM Göral has been registered as new mandarin cultivar in 2011. BATEM Göral have been compared with Clementine mandarin in distinctness, uniformity and stability tests (DUS). In study results showed that 'BATEM Göral' has larger fruit weight and diameter.
World citriculture is dependent on the use of rootstock, transmitting to the cultivated variety a better adaptation to biotic and abiotic stress and ensuring quality production. Trifoliate oranges (Poncirus trifoliata (L.) Raf. ) and their hybrids are commonly used as a rootstock because of their immunity to the tristeza virus while genotypes from the genus Citrus, such as mandarins, are used to confer tolerance to abiotic stresses (limestone, salinity). Poncirus genus diversity seems to be less important and the evaluation of some behavioral variability when subjected to abiotic stress conditions is very limited. For the mandarin group, acid mandarins are often used as rootstock or as a parent rootstock. Sweet mandarins are, on the other side, exploited in varieties breeding programs for fruit quality without knowing their levels of tolerance to abiotic stress.
In this thesis, we studied water deficit and salt stress tolerance for genotypes that are representatives of the diversity for mandarin group and Poncirus.
From the analysis of the genetic diversity of 74 accessions of Poncirus from the INRA -CIRAD germoplasm of San Giuliano (revealed by SSR markers and phenotypes: size of seeds, leaves and flowers), we have established a classification into four genetic groups with one that corresponds to the tetraploid group. Then, using a selection of accessions within these groups, we studied the physiology of seedlings subjected to a water deficit. In another experiment, we characterized the properties of salt stress tolerance of 16 mandarin accessions selected from the different groups based on the molecular diversity. This study was performed on seedlings grown on their roots and on twigs sectioned and subjected to salt stress and for which several physiological parameters (photosynthesis, stomatal conductance...) and biochemical (determination of chloride content and activities of antioxidant enzymes...) were measured. For the Poncirus genus, diversity is primarily organized around two clearly distinct genetic groups at molecular and morphological level. Within each group, the diversity could be only the result of a mutation or a ploidy variation. Furthermore, the study of Poncirus showed that genotypes belonging to genetic group 1 (called “large flower”) are relatively more sensitive to water deficit than genotypes of group 2 (called “small flower”). In the salt stress experiment on mandarins, the tolerance is similar regardless of the "sweet"/"acid" variety classification. However, it seems that the mandarins who inherited portions of genomes of C. maxima or Papeda have better tolerance to salinity. Isolated twigs experiment allows us to study directly the cellular responses at leaf level and to bypass the effect of the root on salt absorption. Therefore, we observed tolerance among varieties such as high leaf concentration of Cl-. The involvement of specific mechanisms that could explain the increased tolerance is also discussed. From these three experiments presented as three journal articles, a selection of genotypes is proposed in order to be used in future breeding programs.
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Sour oranges (Citrus aurantium L.) are well known in the processing and cosmetics industries for the aromatic properties of their essential oils. Intercultivar genetic and aromatic diversity is not well documented. The objective of this study was to evaluate the impact of morphological selection and genetic mechanisms of varietal diversification (mutation or hybridization) on the aromatic and odor variability of sour orange essential oils. Forty-five sour orange accessions from INRAE-CIRAD citrus Biological Resources Center (France) were assessed for ten simple sequence repeat (SSR) and 54 single nucleotide polymorphism (SNP) markers, nine morphochemical fruit traits and with the aromatic components of leaf and peel essential oils. Thirty-nine sour oranges displayed no intercultivar molecular polymorphism and six genotypes originated from interspecific hybridizations involving sour orange, citron, pummelo or mandarin. The peel essential oil (PEO) diversity was low, in accordance with the genetic diversity. The predominance of limonene (>90%) prevents any possible correlation to be made between the composition and the variation in sensory profiles detected by panelists. Few compounds in the leaf essential oil (LEO), such as linalool, linalyl acetate, α-terpineol and geraniol were significantly different across sour oranges varieties. The morphological fruit attributes mainly used in varietal selection differed highly across the main genetically identical group of sour orange accessions. These results confirm that mutation can generate variability in aromatic compounds and aromas and that their exploitation requires an improvement in characterization processes.
Citrus indica Tanaka is a wild endangered and one of the progenitor species of citrus endemic to North East (NE) India, which is reported in Nokrek Biosphere Reserve in the Garo hills of Meghalaya. A wild orange morphologically claimed to be C. indica was encountered in the Dailong forest of Tamenglong district, Manipur which is located in the Indo-Burma biodiversity hotspot region. Surveys were conducted to establish the exact identity of possible C. indica and study the natural habitat in Dailong forest area. The traditional morpho-taxonomic description for the identification of the plant is performed along with the molecular characterization using three chloroplast regions ( trnL-F , psbK-I , matK-5′trnK spacer) and one nuclear (ITS) region. Phylogenetic analysis revealed that the C. indica found in Dailong Forest is monophyletic with the earlier reported C. indica sequence from Garo hills, Meghalaya. Both morphological and molecular data support the identity of C. indica that has been collected from Manipur. However, lack of knowledge and clearing of forest cover has led to an urgent need for the implementation of conservation strategies to safeguard this endangered species. This study supports the evidence that NE India is one of the origin centres for citrus and this finding can guide the conservationists to initiate priority for adopting possible methods of proper conservation of C. indica in the region.
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