Sweet Orange Cultivars Research Articles

Effort to Enhance Storability of Nepali Sweet Orange (Citrus sinensis) under Different Storage Conditions

Nepali sweet orange (Citrus sinensis) cultivars are grown in mid hills and are considered to be exquisite in taste. It is mostly harvested during December-January that fetches poor market price. Farmers try to delay picking by retaining fruit on tree compromising tree health and production for next season. Further in some places farmers try to store in normal room and cellar storage facility with considerable amount of post-harvest loss. Recently cool bot storage facility has been introduced to storage horticulture commodities. Thus an experiment was set to study the effect of various storage structure on shelf life of sweet orange at National Citrus Research Program, Dhankuta, Nepal. Four types of storage facilities (zero energy, cellar, cool bot and normal room) were used to store sweet orange fruit over 90 days. Freshly picked Dhankuta Local sweet orange fruit with small pedicel intact were used for this study in RCB design with four treatments replicated four times. Physiological loss in weight (PLW), fruit rot percent, juice recovery percent, TSS and TA were recorded at weekly interval. The result revealed that there was no significant difference in chemical quality parameters (TSS and TA) due to storage method. However, juice recovery and PLW was better in cool bot and cellar stored fruit with ≤15% fruit rot when waxed fruit were stored at 10-12°C with more than 85% RH. In a constant supply of electricity, cool bot storage could be better option compared to other storage facilities for sweet orange storage up to three months

Pre-harvest field application of enhanced freshness formulation reduces yield loss in orange

BackgroundOrange (Citrus sinensis L.) production in Tanzania is constrained by several pre-harvest factors that include pests. Hexanal, sprayed as Enhanced Freshness Formulation (EFF) is a relatively new technology that has been reported to reduce pre-harvest loss in fruits. However, the effects of hexanal on pre-harvest yield loss of orange are not known. We studied the effects of hexanal as EFF on yield losses of three sweet orange cultivars namely, Early Valencia, Jaffa, and Late Valencia. Factorial experiments tested the effects of EFF concentration, variety, and time of EFF application on number of dropped fruit, percentage of non-marketable fruit and incidence of pest damage.ResultsResults showed significant negative correlation (p < 0.001) between EFF and the percentage of dropped fruit, non-marketable yield, and incidence of pest damage. An increase in hexanal concentration by 1%, is expected to reduce number of dropped fruit by 50, percentage of non-marketable by 35.6, and incidences of pest damage by 36.5% keeping other factors constant. Results also show significant association (p < 0.001) between time of hexanal application and non-marketable yield. Percentage of dropped fruit is expected to increase by 1 for each day away from harvest, keeping other factors constant.ConclusionPre-harvest application of hexanal as EFF can significantly reduce number of dropped fruits, percentage of non-marketable fruit and incidence of pest damage.

Assessment of Two Sweet Orange Cultivars Grafted on Selected Rootstocks Grown on an Inceptisol in Puerto Rico

Sweet oranges in Puerto Rico and other citrus-producing areas in the world have been greatly affected by the Huanglongbing disease (HLB). Historically, most of Puerto Rico’s citrus production has been located from 0–600 m above sea level, where fruit acquire a desirable color and flavor due to climatic conditions. However, higher populations of the disease vector Diaphorina citri Kuwayama have been reported at these elevations in Puerto Rico. Although only 6.4% of the land area is located above 600 m, it is composed mainly of environmentally sensitive or non-arable land where Inceptisols are the dominant soil order. For that reason, ‘Marr’s Early’ and ‘Pera’ sweet orange (Citrus sinensis) scions grafted on ‘Carrizo’, ‘HRS 802’, and ‘HRS 812’ rootstocks were planted in Alonso clay series Inceptisol (Oxic Humudepts) at 649 m in 2010. Tree growth parameters (height, diameter, canopy volume) and yield efficiency were measured. Fruit quality was determined from juice content (%), total soluble solids [°Brix], and pH. Leaf tissue analyses showed an optimum range for Ca, Mg, Na, P, B, Cu, and Zn, an indicator of tree health. A few were high (i.e., N and P) or in excess (i.e., Fe), but no clear connection to specific scions or rootstocks could be established. Tree height, tree diameter, fruit production, and juice content were higher in both sweet oranges grafted on ‘HRS 802’ compared with those on ‘HRS 812’ and ‘Carrizo’. Therefore, ‘HRS 802’ rootstock can be recommended to local farmers growing sweet oranges in Alonso series soil.

Volatile Organic Compounds Profiles to Determine Authenticity of Sweet Orange Juice Using Head Space Gas Chromatography Coupled with Multivariate Analysis.

An efficient and practical method for identifying mandarin juice over-blended into not from concentrate (NFC) orange juice was established. Juices were extracted from different cultivars of sweet orange and mandarin fruits. After being pasteurized, the volatile organic compounds (VOCs) in the juice samples were extracted using headspace solid-phase microextraction, and qualitatively and quantitatively analyzed using gas chromatography–mass spectrometry detection. Thirty-two VOCs contained in both the sweet orange juice and mandarin juice were used as variables, and the identification model for discriminating between the two varieties of juice was established by principal component analysis. Validation was applied by using common mandarin juices from Ponkan, Satsuma and Nanfengmiju cultivars blended at series of proportions into orange juices from Long-leaf, Olinda, and Hamlin cultivars. The model can visually identify a blending of mandarin juice at the volume fraction of 10% or above.

Rootstock influences the metabolic response to Candidatus Liberibacter asiaticus in grafted sweet orange trees

In a grafted citrus tree, the leaf and root metabolic composition and the response to the phloem-limited pathogenic bacterium Candidatus Liberibacter asiaticus are influenced by the rootstock. Eleven different citrus rootstock varieties were investigated for their influence on the grafted tree response to Candidatus Liberibacter asiaticus (CLas), the pathogen associated with Huanglongbing (HLB). Rootstocks included mandarin and sweet orange cultivars, sour orange, and hybrids of citrus and trifoliate orange. Leaves and roots of healthy and CLas-infected greenhouse-grown plants were collected 6 months after graft inoculation and metabolite profiles were assessed by untargeted gas chromatography–time-of-flight-mass spectrometry (GC–TOF-MS). The genetic origin of the rootstock determined their metabolic profiles in the healthy state and influenced the root metabolic response to CLas. In the leaves, metabolic differences were determined by the tree response to CLas and to a lesser extent by the rootstock cultivar on which the plants were grafted. Among the leaf metabolites that responded most consistently to infection were citrulline, ornithine, and quinic acid, which were upregulated in infected plants. The reverse was found for cerotinic acid, cyanoalanine, hexadecane, and raffinose. In both leaves and roots, several metabolites associated with plant stress and disease tolerance such as benzoic acid and proline responded differently in plants on the mandarin × trifoliate hybrid rootstocks compared with the other rootstocks. This corresponds with the different HLB field tolerance of grafted trees on different rootstocks, which is generally higher in combination with some mandarin × trifoliate hybrids. Our results demonstrate the influence of rootstock on the grafted tree response to CLas and underscore the importance of rootstocks for disease management in an HLB-endemic environment.

2019–2020 Florida Citrus Production Guide: Brown Rot of Fruit

Management of brown rot, caused by Phytophthora nicotianae or P. palmivora, is needed on both processing and fresh-market fruit. While the disease affects all citrus types, it is usually most severe on Hamlin, Navel, and other early-maturing sweet orange cultivars. This 3-page fact sheet is part of the 2019–2020 Florida Citrus Production Guide. Written by M. M. Dewdney, E. G. Johnson, and J. H. Graham, and published by the Plant Pathology Department, March 2019. PP-148/CG022: 2022–2023 Florida Citrus Production Guide: Brown Rot of Fruit (ufl.edu)

Response of sweet orange cultivars budded on Carrizo at different time intervals

Response of sweet orange cultivars budded on Carrizo at different time intervals

Desempenho de dois pomares adultos de laranjeira ‘Pêra’ no oeste de Santa Catarina, Brasil

The sweet orange cultivar 'Pera' [( Citrus sinensis L.) Osb.] is the most important in Brazil due to its good adaptation in the Southeast region and the quality of its juice. However, it is susceptible to citrus tristeza, a disease that is more severe in cold climates such as subtropical ones. Thus, its cultivation in this region is limited. The objective of this study was to evaluate the potentiality of 'Pera Bianchi' orange for cultivation in the Santa Catarina state. Two adult 'Pera Bianchi' orchards located in the west of the state were evaluated. Plant size, fruit production and its quality (size and juice characteristics) were evaluated during two harvests. 'Pera Bianchi' orange presented satisfactory yearly productivity, averaging the equivalent to 42 and 45t ha -1 , and its juice quality was adequate to market standards. However, a large portion of the fruit produced is not adequate in size for commercialization as fresh fruit. Regarding fruit productivity and size, there was a substantial variability among plants in the same orchard.

Detection of natural and induced mutations from next generation sequencing data in sweet orange bud sports

Somatic mutations are a cause of intraspecific diversity in many fruit crops, including citrus. In the case of sweet orange [Citrus sinensis (L.) Osbeck], intraspecific variability is determined only by somatic mutations. Tools for clonal fingerprinting are required by breeders and nurserymen and have important implications for traceability. With the aim of studying genomic variability and identifying mutational events responsible for varietal diversification, we deep-resequenced 22 accessions including navel, common and blood oranges using an Illumina platform. We also resequenced an induced mutant of Tarocco 'Scire D2062' obtained using two cycles of gamma ray irradiation at 40 Gy. A robust and reliable set of single nucleotide polymorphisms (SNPs), structural variants (SVs) and indels, specific of each accession or common to varietal groups, was identified both in natural and induced mutants. A subset of SNPs, transposable element insertions and small indels (2 to 18 base pairs) was validated by Sanger sequencing, PCR amplification and high resolution melting analysis, confirming the results of the bioinformatics analysis. Moreover, to identify a reliable marker set for traceability of specific cultivars, we collected leaf and juice samples from many Italian citrus growing areas and used a KASP platform for their fingerprinting. These tools will be useful to prove true-to-typeness of specific sweet orange cultivars.

Genome-wide identification and transcript analysis of vacuolar-ATPase genes in citrus reveal their possible involvement in citrate accumulation

The vacuolar H+-ATPase (V-ATPase) proton pump plays an important role in the acidification of vacuoles; however, genes encoding V-ATPase in the citrus genome and their roles in citric acid accumulation remain unclear in citrus fruit. In this study, we found at least one gene encoding subunit A, B, C, D, G, c’’, d or e; two genes encoding the subunit E, F, H or a; and four genes encoding subunit c in the citrus genome. Spatial expression analysis showed that most genes were predominantly expressed in the mature leaves and/or flowers but were less expressed in root and juice cells. Two sweet orange (Citrus sinensis) cultivars, ‘Anliu’ (AL) and ‘Hong Anliu’ (HAL), which differ in terms of fruit acidity, were used in this study. The citric acid content was significantly higher in ‘AL’ fruits than in ‘HAL’ fruits over the entire experimental period (82 days–236 days after full blossom, DAFB). Transcript analysis showed that the transcript levels of most subunit genes, including V1-A, V1-B, V1-C, V1-E1, V1-G, V1-H2 and V0-a2, V0-c”, V0-c4, and V0-d, were significantly lower in ‘HAL’ than in ‘AL’ fruits during fruit development and ripening. Moreover, ABA injection significantly increased the citric acid content, simultaneously accompanied by the obvious induction of V1-A, V1-C, V1-E1, V1-F1, V1-H2, V0-a1, V0-a2, V0-c1, V0-c2, V0-c4, and V0-d transcription levels. In conclusion, the results demonstrated that V1-A, V1-C, V1-E1, V1-H2, V0-a2, V0-c4, and V0-d may play more roles than other subunit genes in the vacuole acidification of citrus fruits. The lower activity of V-ATPase caused by the transcript reduction of some subunit genes may be one reason for the low citrate accumulation in ‘HAL’ juice sacs.

2018–2019 Florida Citrus Production Guide: Brown Rot of Fruit

Management of brown rot, caused by Phytophthora nicotianae or P. palmivora, is needed on both processing and fresh market fruit. While the disease affects all citrus types, it is usually most severe on Hamlin, Navel, and other early maturing sweet orange cultivars. This 2-page fact sheet is part of the 2018–2019 Florida Citrus Production Guide. Written by Megan M. Dewdney, Evan G. Johnson, and James H. Graham, and published by the Plant Pathology Department, May 2018. PP-148/CG022: 2022–2023 Florida Citrus Production Guide: Brown Rot of Fruit (ufl.edu)

Determination of citrus juice coumarins, furanocoumarins and methoxylated flavones using solid phase extraction and HPLC with photodiode array and fluorescence detection

A synergistic combination of analytical techniques was developed for the simultaneous determination of the three most biologically active chemical families in citrus juices: methoxylated flavones, coumarins, and furanocoumarins. No rapid methodology has been available to determine them together. A solid phase extraction concentrated these groups and a ternary reverse phase HPLC gradient completely resolved them from other juice components. Two coumarins, isomeranzin and osthole, were identified in a sweet orange (C. sinensis) cultivar, Changyecheng, for the first time. Pummelo juice was characterized by coumarin and furanocoumarin epoxides such as meranzin and epoxybergamottin. No epoxides were observed in the more acidic juices. Added furanocoumarin epoxides hydrolyzed rapidly in the most acidic juices. The ratios of the UV peak areas at 320 nm to the fluorescence emission peaks as well as the ratio of fluorescence emission peaks at 450–400 nm could be used to identify chromatographic peaks.

Effects of postharvest storage conditions on ‘Tarocco’ orange fruit quality

'Tarocco Sant'Alfio' [Citrus sinensis (L.) Osbeck] is a late ripening sweet orange cultivar belonging to the so called “blood oranges”. These fruits are more and more appreciated from consumers for their high nutraceutical value due to the presence of anthocyanins in the flesh. Recently, cold treatment in sweet orange has received more attention due to its usefulness for accomplishing phytosanitary exportation rules, allowing Italian citrus fruit to be sent to Japan and the USA. In addition, cold treatments are useful for increasing pigmentation levels in the fruit. The aim of this work was to define a reliable protocol for postharvest storage of the very-late 'Tarocco Sant'Alfio' blood orange to prolong the availability of this product in the market to be used for fresh squeezed orange juice production. Fruits were subjected to three storage treatments (20 days at 1°C plus 50 days at 4°C; 70 days at 4°C; 70 days at 20°C, as control). The results indicate that cold treatments, in particular at 4°C constantly, can extend 'Tarocco Sant'Alfio' shelf life and might enhance its qualitative value determining an increase of total anthocyanin content in the flesh. The defined protocols allow prolonging market availability of such a high value product till late June with relevant benefits for the citrus industry and advantages for consumers.

Improving Navel orange (Citrus sinensis L) productivity in Delta Region, Egypt

The objective of this work presents general information about the Washington Navel sweet orange cultivar (Citrus sinensis L.) productivity in Delta region, Egypt, over the next few years, focusing on increasing total yield and enhancement fruit quality by following good agricultural practices, and increasing alertness among growers of the need for implement fruit quality to compete in the global market. Some of the practices include usingproper fertilizers, irrigation technique, pruning, integrated pest management and harvest technique.

Viroid infection and rootstocks affect productivity and fruit quality of the Tunisian citrus cultivar Maltaise demi sanguine

In Tunisia, sweet orange citrus cultivars are usually grafted on sour orange rootstock. However, this rootstock is susceptible to Citrus tristeza virus (CTV). A trial was established in 2005 to evaluate the performance of newly introduced rootstocks compared to sour orange, using the sweet orange cultivar ‘Maltaise demi sanguine’ as the grafted scion. The effect of single or mixed viroid infections were monitored over 12 years. Once established, tree growth, cumulative yield, tree performance and fruit quality of ‘Maltaise sweet orange’ were assessed from 2008. Mixed viroid infections caused significant decreases (39 to 60%) in the canopy volume of ‘Maltaise’ grafted on Carrizo citrange, Swingle citrumelo, Cleopatra mandarin, Rangpur lime, Volkamer lemon and Trifoliate orange. The cumulative yield of trees grafted on’Alemow’ ( Citrus macrophylla ) and inoculated with Hop stunt viroid (HSVd) was 76% less than the healthy control. Mixed infections caused production decreases of 56% from trees grafted on Swingle citrumelo and 69% from those grafeted on Trifoliate orange. When quality parameters of fruit from trees infected with each viroid, and combinations of viroids were compared, no significant differences were recorded.

Pre-harvest spray application of abscisic acid (S-ABA) regulates fruit colour development and quality in early maturing M7 Navel orange

Abstract Poor fruit colour development at harvest in early maturing M7 sweet orange cultivar causes economic losses to the growers. The responses of different concentrations (50, 100, 200, 300 or 500 mgL−1) of abscisic acid (S-ABA) and its biosynthesis inhibitor nordihydroguaiaretic acid (NDGA) (0.01, 0.02, 0.04 mM) at pre-harvest stage (6 or 3 weeks before anticipated harvest) on peel colour development particularly from yellow to deep orange and on the fruit quality of M7 were studied during 2015 and 2016 in Western Australia. S-ABA treatments during both years irrespective of the concentrations applied exhibited significantly lower hue angle (h°) with enhanced citrus colour index (CCI) and higher levels of total carotenoids in the flavedo during 2015 and 2016. Spray application of S-ABA (300 and 500 mg L−1) resulted in higher level of total carotenoids (35.0 and 71.5 mg kg−1) in the flavedo during 2015 and 2016. A single spray application of S-ABA applied at 6 weeks before anticipated harvest (WBAH) showed higher mean CCI (10.1) and level of total carotenoids (37.6 mg kg−1) as compared to its single application at 3 WBAH and double spray at 6 WBAH followed by 3 WBAH in 2015. However, nordihydroguaiaretic acid (NDGA) restricted colour development indicated by higher h° and reduced CCI with lower levels of total carotenoids in the flavedo during 2015. S-ABA treatments exhibited significantly reduced total organic acids in the juice, whilst total sugars were not affected by any of the treatments. S-ABA treatments (200 and 300 mg L−1) showed increased SSC/TA ratio (12.8%) as a result of reduction in total acidity (TA) (0.96%). In conclusion, pre-harvest spray application of S-ABA promoted fruit colour development from yellow to deep orange, indicated by reduced h° and increased CCI as well as the levels of total carotenoids in the flavedo of M7 Navel orange. Promotion of fruit colour development (yellow to deep orange) with the pre-harvest application of S-ABA and its down regulation with the application of ABA biosynthesis inhibitor (NDGA) suggested the involvement of S-ABA in flavedo colour development in M7 Navel orange fruit.

The Effect of Huanglongbing on Young Citrus Tree Water Use

Understanding the role of Huanglongbing (HLB) caused by Candidatus Liberibacter asiaticus on citrus (Citrus sp.) water use is critical for determining if changes in water management of commercial citrus orchards affected by this disease is necessary. Reference evapotranspiration (ETo) is the most used methodology for irrigation scheduling, particularly in light of reports that indicate the lack of water for irrigation will become a major problem in many places around the world including Florida. The objectives of this study were to determine citrus tree water relationship [water use, sap flow, and stem water potential (Ψ)] as affected by ETo and HLB. The study was initiated on Jan. 2014 on two sweet orange (Citrus sinensis) cultivars included Hamlin and Valencia grown in a fine sandy soil texture (sandy, siliceous, and hyberthermic Arenic Alaquods) in a greenhouse. Twelve weighing lysimeters of each cultivar (six HLB-affected and six nonaffected trees) were used to determine selected water relation parameters. Results indicated a significant reduction in water use, Ψ, and sap flow for affected trees when compared with nonaffected trees. Citrus water use of healthy trees during the 2-year study was 31% and 27% greater than HLB-affected trees for ‘Hamlin’ and ‘Valencia’, respectively. Lower water use of HLB-affected trees resulted in 10% and 15% greater available soil water content than healthy ‘Hamlin’ and ‘Valencia’ trees, respectively. Therefore, reducing the water supply for HLB-affected trees than healthy trees may be a desirable practice that would lead to significant water savings.

Rootstock-modulated yield performance, fruit maturation and phytochemical quality of ‘Lane Late’ and ‘Delta’ sweet orange

Graft combinations of sweet orange cultivars Delta and Lane Late on six rootstocks were established on calcareous clayey soil and evaluated for compatibility, yield, and fruit physicochemical quality attributes at three stages of harvest maturity. Citrumelo proved a deleterious rootstock to both scions, while GouTou was deleterious to Delta and had low compatibility with Lane Late. Most compatible rootstock for Delta was Sour Orange, whereas all rootstocks except GouTou were equally compatible with Lane Late. Yield and fruit weight were highest on Volkameriana. Titratable acidity was highest on Sour Orange and Carrizo and lowest on Volkameriana. Dominant acids were citric (8.5–11.3g/L), malic (1.8–1.9g/L) and succinic (1.3–1.4g/L). Citrate/malate ratio was lower in Lane Late and declined further with maturation. Acids were highest on Sour Orange and Carrizo. Increased levels of malate (2.07–2.21g/L) elicited by Volkameriana may constitute an index of inferior sensory quality. Soluble solids were highest on Sour Orange, Carrizo and Cleopatra (9.6–10.6%) and lowest on Volkameriana (9.3–9.7%). Sucrose was the most abundant soluble carbohydrate (33.9–39.9g/L) and sugar ratios were stable across rootstocks, however sucrose concentration in Delta increased with maturity at the expense of glucose and fructose. Increase in chroma paralleled increase in soluble solids during maturation of Delta but not Lane Late. Fruit phenolics were highest with the least compatible GouTou and lowest with the highly productive Volkameriana. Maximal ascorbate levels were attained at mid-maturity (380.4–450.2mg/L) and were lowest on Volkameriana (323.4–398.8mg/L). Considering its overall performance and resistance to Citrus Tristeza Virus, Carrizo appears as a promising rootstock alternative to Sour Orange particularly on calcareous soils.

Assessment on performance and variability in different sweet orange (Citrus sinensis Obseck) cultivars under Punjab conditions

Based on morphological characterization, the performance of eighteen sweet orange, (Citrus sinensis Obseck) cultivars were evaluated. On the basis of two year data, the maximum mean fruit weight (316.25 gm) was recorded in Moro, while the maximum mean fruit diameter and mean fruit length was recorded in Mosambi and Olinda Valencia (87.32 mm and 81.33 mm, respectively). Albedo thickness was recorded maximum in Ruby Nucellar (3.42 mm). Highest total soluble solids was recorded in cultivar Moro (11.450 brix), while the titratable acidity was recorded maximum in Valencia Calizonida (1.21 %). Fruit axis diameter and Fruit rind thickness were recorded maximum in Rhode Red Valencia and Vernia (15.12 mm and 8.11 mm, respectively). In the variability studies, the maximum genotypic coefficient of variance (GCV) and phenotypic coefficient of variance (PCV) was recorded maximum for titratable acidity (27.88 and 27.94, respectively) followed by albedo thickness (23.77 and 23.78, respectively) and fruit weight (21.52 and 21.67, respectively). Genetic advance per cent of mean was recorded for titratable acidity (57.31%) followed by albedo thickness (48.96 %) and fruit weight (44.03 %) suggesting that further selection will be effective for improvement in these traits.

Physikalisch-chemische Profilerstellung vielversprechender Sorten der süßen Orange, die unter verschiedenen agroklimatischen Bedingungen in Pakistan wachsen

Sweet oranges are produced on large scale all over the world and demanded due to less number of seeds and are better juice quality. A study was carried out with the objective to characterize promising sweet orange cultivars for better quality fruits production under different agro-climatic conditions of Punjab (Pakistan). Fruits of three promising sweet orange (Citrus sinensis L. Osbeck) cultivars viz. ‘Blood Red’, ‘Musambi’ and were harvested from commercial citrus groves at five different locations. Starting from Multan, in the direction of increasing altitude, four more sites viz. Sahiwal, Faisalabad, Sargodha and Chakwal were selected after every 100–150 km distance. Fruits were evaluated in terms of different physical and biochemical characters. Results showed significant influence of climatic conditions on physico-chemical properties of the cultivars at all the locations. Fruits harvested from Multan and Sahiwal showed higher fruit weight, diameter and peel weight. More juicy fruits with higher vitamin C content were produced under mild temperature environmental conditions of Chakwal. Overall, ‘Musambi’ fruits had more total soluble solids and reducing and total sugars. ‘Musambi’ was found to be good source of bioactive compounds i. e. vitamin C and total phenolic content, had the maximum antioxidant activity as compared to ‘Blood Red’ and ‘Succari’ and may be explored as potential cultivar in Sargodha and Chakwal.