Effect of Sustained Deficit Irrigation on Stem Water Potential of Navel Oranges in Jordan Valley

Research was conducted to find the relationship between deficit irrigation treatments （DIT） and stems water potential. The study was conducted on 14 years old navel orange trees grafted on sour oranges for the growing season 2006/2007 at a private farm in the Northern part of Jordan Valley （latitude： 32° 50′ N, longitude： 32° 50′ E, altitude： -254 m）. Three levels of irrigation treatments （IT） were applied; namely 100%, 75% and 50% of reference evapotranspiration, representing over irrigation （OIT）, full irrigation （FIT）, and deficit irrigation （DIT）, respectively. A drip irrigation using one irrigation source line with drippers spaced 0.5 m having average discharge of 2.3 L/hr at pressure 1.5 bar, was used. Stem water potential （SWP） at 100% over irrigation treatment （OIT） of navel orange trees had less negative value during the irrigation seasons （-1.57 MPa）, whereas the highest negative value （-2.17 MPa） occurred at 50% deficit irrigation treatment （DIT）.

Dynamic Changes of Sugar Concentrations in Pulp of ‘Cara cara' Navel Orange(Citrus. sinensis L. Osbeck) after Application by Exogenous ABA and GA_3

The dynamic concentrations of glucose, fructose, sucrose and total sugar were determined through exogenous ABA and GA3 treatments during young period of fruit and before fruit coloring in pulp of ‘Cara cara’ navel orange. The results are as fol ows： 10 mg/L ABA increased glucose, fructose and total sugar concen-tration significantly or very significantly, ABA treatment of 50 mg/L increased sucrose concentration very significantly, but ABA treatment of 100 mg/L decreased glucose concentration very significantly. GA3 treatment of lower and middle concentrations（10, 50 and 250 mg/L） increased sucrose concentration very significantly, GA3 treatment of 10 mg/L had no remarkable effect on glucose and fructose concentration but in-creased total sugar concentration very significantly, GA3 treatment of 50, 250 and 500 mg/L decreased glucose, fructose and total sugar concentration very significant-ly. Therefore, ABA treatment of lower concentration could increase one or several kinds of sugar concentration, but GA3 treatment of higher concentration （250 and 500 mg/L） restrained sugar concentration in pulp of ‘Cara cara’ navel orange seri-ously.

Evaluation of Washington Navel Orange Economic Indicators

In Egypt, oranges are the most important citrus crops for local consumption or export. It represents approximately 72.2% of the total Egyptian citrus production in 2019/2020. The main cultivated variety of orange is the Washington navel orange and it is more popular because of its delicious taste, nutrition, and its seedless besides being rich in vitamin C. Washington navel orange is susceptible to fruit cracking, and it is a common physiological disorder that takes place during fruit development. This work aims to investigate the negative effect of fruit cracking in reducing the yield and quality of Washington navel orange produced in Egypt by studying major economic indicators and estimating an economical evaluation of using treatment of Washington navel orange during the period time of 2007/2008 until 2019/2020. Results showed that fruit areas and production of Washington navel orange represented about 52.9% and 53.2% of fruit areas and production of orange during the study period. However, the yield was unstable with a significant annual growth rate of about 1.1%. Also, the last mentioned treatment achieved a high price for farmers by about 5.1% and total revenue of about 3.2% during the study period. Nowadays, Egypt has become the largest exporter of oranges in the world within the last year and the achieved earnings reached $661 million in 2019/2020. In addition, results showed that evaluation of using a treatment to reduce the rate of Washington navel orange cracking was economical to be applied.

Effect of harvest time on the chemical composition and antioxidant capacity of Gannan navel orange(Citrus sinensis L. Osbeck 'Newhall')juice

The present study investigates the chemical composition and antioxidant capacity of juice from the Gannan navel orange, which is harvested at one-to two-week intervals during the ripening period. The total soluble solid(TSS), total polyphenol content(TPC), total flavonoid content(TFC), sucrose and hesperidin contents gradually increase with the ripening of the fruit, followed by slight declines at the late maturity stage. Contrary to these observations, the contents of titratable acid(TA), vitamin C(Vc), and limonin trend downward throughout the ripening period. However, the contents of fructose, glucose, and narirutin fluctuate throughout the harvest time. Three in vitro antioxidant assays consistently indicate that the harvest time exerts no significant influence(P>0.01) on the antioxidant capacity. Furthermore, principal component analysis(PCA) and Pearson’s correlation test are performed to provide an overview of the complete dataset.This study provides valuable information for evaluating the fruit quality and determining when to harvest the fruit in order to meet the preferences of consumers. Meanwhile, our observations suggest that the fruits subjected to juice processing should be harvested at the late maturity stage to alleviate the "delayed bitterness" problem without compromising the antioxidant capacity and the flavonoid content in the juice.

Application of Wavelet Transform in the Prediction of Navel Orange Vitamin C Content by Near-Infrared Spectroscopy

This study was to search for an approach for rapid measurement of orange vitamin C （Vc） content. By using different decomposing levels of Daubechies 3 wavelet transform, the near-infrared spectra signals obtained from intact fruits of 100 navel orange samples were denoised, and the results of the predicted Vc contents for the corresponding samples determined by the reconstructed spectra after denoising were validated by means of PLS-CV （partial least squared-cross validation）. It was shown that the prediction effects verified by PLS-CV analysis varied when different wavelet transform decomposing levels were employed. At the wavelet decomposing level 4, the best prediction effect was obtained, with the correlation coefficient R between the prediction and true values being 0.9574 and the expected variance RMSECV being as low as 3.9 mg 100 g^-1. Furthermore, the 11 different approaches for the pretreatment of the near-infrared spectrum were compared. It was found that the calibration model established by PLS using spectra pretreated by wavelet transform denoising provided the best prediction for Vc content, exhibiting the highest correlation between the prediction and true values by cross validation. In conclusion, the near infrared spectral model denoised by means of wavelet transform can be used for accurate, rapid, and nondestructive quantitative analysis on navel orange Vc content.

Ca(NO3)2 canopy spraying during physiological fruit drop period has a better influence on the tree character and fruit quality of Newhall navel orange(Citrus sinensis Osbeck)

This study aimed to provide a theoretical basis for adopting suitable cultivation measures to tackle calcium （Ca） deficiency in citrus leaves. The Newhall navel orange （Citrus sinensis Osbeck） canopy was sprayed with 20.0 mmol L-1 of Ca（NO3）2 during physiological fruit drop period, fruit expanding period, and fruit maturing period on 30, 90, and 210 days after full bloom （DAFB）, respectively, and its effects on leaf gas exchange parameters and leaf mineral nutrition and fruit quality were analyzed. The results showed that： （1） The photosynthetic rate （ACO2） at 9：00 a.m. and 16：00 p.m. of fruit expanding period with 30 and 90 DAFB Ca（NO3）2treatments slightly or significantly improved mainly by decreasing stomatal limitation and nonstomatal limitation, respectively. （2） Compared with control （CK）, the Ca concentration in leaves with 30, 90, and 240 DAFB Ca（NO3）2 treatments increased by 127.16; 97.53, and 33.33%, respectively, and the leaf magnesium concentra- tion also increased by more than 32.26%. However, Ca（NO3）2 canopy spraying on 30 DAFB significantly reduced the leaf potassium concentration, by 22.14% compared with CK. （3） Ca（NO3）2 canopy spraying on 30 DAFB decreased the second fruit drop rate by 30.55% and increased the weight per fruit by 25.04%, thus resulting in a significant increase in citrus yield. （4） Spraying Ca（NO3） on 30 DAFB mainly affected the metabolism of titratable acid （TA） to improve the maturity of citrus fruits. Whilst it improved the external quality and the coloring of citrus fruit significantly. Therefore, Ca（NO3）2 canopy spraying during physiological fruit drop period has a better influence on the tree character and fruit quality of Newhall navel orange （Citrus sinensis Osbeck）.

The effects of rootstocks on performances of three late-ripening navel orange varieties

Selection of rootstock is very important for citrus production. Besides its major role on resistance, the rootstock also can affect fruit production and quality. Currently, the main concerns on selection of rootstock for citrus production are compatibility and resistance, due to less information on the impacts of rootstock to the performance of scion varieties. This study aims to provide information on performances of navel orange varieties on different rootstocks. Three late-ripening navel orange varieties(Citrus sinensis var. Powell, Chislett and Banfield) grafted on seven rootstocks(Swingle citrumelo(C. paradisi× P. trifoliata), Carrizo citrange(C. sinensis×P. trifoliata), X639(C. reticulata×P. trifoliata), MXT(C. sinensis×P. trifoliata), Hongju(C. reticulata), Ziyang Xiangcheng(C. junos) and trifoliate orange(P. trifoliata)) were used as plant materials for comprehensive comparison of the performances on tree growth, fruit yield and quality in 21 scion–stock combinations. Investigation was carried out in these combinations in field nine years after planting. Vigorous growth of all the three late-ripening navel orange varieties was observed on Carrizo citrange with the largest canopy volume at 33.34 m3 and the highest yield at 29.43 kg per tree, but a low yield efficiency at 2.87 kg m–3. On the contrary, those on trifoliate orange had the smallest canopy volume at 10.79 m3 and the lowest fruit yield at 12.51 kg per tree, but the highest yield efficiency at 3.95 kg m–3. Rootstocks did not show significant effects on fruit size, fruit shape index, peel thickness and the edible rate of the fruits, but fruit quality was significantly affected by the rootstocks. Fruits from the trees grafted on trifoliate orange presented the best quality with significantly higher total soluble solids(TSS) content than those on Ziyang Xiangcheng and Hongju, and also the highest ratio of TSS/titratable acidity(TA). The TA content was observed from the fruits on X639 at 0.59 g 100 mL–1. Vitamin C(Vc) content of fruits on Hongju was the highest at 49.25 mg 100 mL–1. Growth vigor of the trees was positively correlated with fruit yield at an extremely significant level. The canopy volume was negatively correlated with yield efficiency, but positively correlated with compatibility index. Results of this study indicated that the rootstock has great impacts on the growth vigor of the tree, yield efficiency and quality of the fruit. In order to achieve good quality and yield efficiency for navel orange production, less growth vigor rootstock such as trifoliate orange is highly recommended.

Constraints of Quality and Marketing of Gannan Navel Orange and Measures for Industrial Development

In order to provide reference for the sustainable development of Gannan navel orange industry,this paper analyzed constraints of quality and marketing of Gannan navel orange. From developing the dominant area of the navel orange and ensuring high quality healthy development of navel orange,it came up with sustainable development recommendations for Gannan navel orange industry,to realize high quality,efficient,and deep development of Gannan navel orange industry in both the area and quantity,and change from simple planting and sales to fresh fruit sales,deep processing,and tourism combined development.

Physiological changes and expression characteristics of ZIP family genes under zinc def iciency in navel orange(Citrus sinensis)

Zinc （Zn） deficiency is widespread among citrus plants, but information about the mechanisms for Zn deficiency response in these plants is scarce. In the present study, different navel orange （Citrus sinensis （L.） Osbeck） leaves with various yellowing levels were sampled in our experimental orchard, and upon estimation of nutrient contents, Zn deficiencies were diagnosed as mild, moderate, and severe. Further analysis of chlorophyll content, photosynthetic characteristics, antioxidant enzyme activities, and expression levels of Zn/Iron-regulated transporter-like protein （ZIP） family genes were conducted in the sampled Zn-deficient leaves. The results showed that chlorophyll contents and net photosynthetic rate （Pn） seemed to decrease with reduced Zn contents. In addition, comparison of severe Zn-deficient and normal leaves revealed that activities of peroxidase （POD） and catalase （CAT） increased significantly, whereas that of Zn-containing enzymes such as Cu/Zn superoxide dismutase （Cu/Zn-SOD） significantly reduced with decreasing Zn contents. As expected, expression of the ZIP family genes, ZIP1, ZIP3, and ZIP4, was induced by Zn deficiencies. These results deepen our understanding of Zn deficiency in citrus plants as well as provide useful preliminary information for further research.

Correlations between Light Rare Earth Elements in Soil and Navel Orange Tree System in Gannan Area

The total content of light rare earth elements( LREEs) in the soil of navel orange orchards of Gannan area is greater than that of heavy rare earth elements( HREEs). Appropriate content of LREE can not only promote the growth of navel oranges,and it is also conducive to human health. On the basis of exploring the correlations between the content of LREE in the soil of navel orange orchards of Gannan area and the contents of LREE in navel orange leaves and fruit,the influence mechanism of LREEs on the quality of navel oranges was revealed. In this study,with two Newhall navel orange orchards with different soil LREEs background levels in Xinfeng County as the research object,the changes in the content of LREE( lanthanum,La; cerium,Ce; praseodymium,Pr; neodymium,Nd) in leaves and fruit of navel orange at different growth stages were analyzed using Inductively Coupled Plasma-Mass Spectrometry( ICP-MS),and the correlations between the content of LREE in the soil,navel orange leaves and navel orange fruit were studied. The results showed that the contents of the four kinds of LREEs in the soil ranked as Ce > La > Nd > Pr,and there were significant differences among them( P < 0. 01). Navel orange leaves and fruit have selective and heterogenic absorption for LREEs. At different growth stages,La showed the highest accumulation amount in the leaves and fruit of navel orange; and the content of LREE in the leaves of navel orange increased first and then decreased,while that in the fruit of navel orange showed continuous decrease. During the migration of LREEs from soil to leaves to fruit,the content of LREE decreased rapidly as the migration distance increased. The accumulation amount of LREE in navel orange was positively correlated with the content of LREE in the soil. The correlation between the content of LREE in the leaves and fruit of navel orange was greatest. Among the four kinds of LREEs,the correlation of La was greatest,followed by Ce,indicating that the accumulation amount of LREE in the navel orange body was affected by the element types.

AFLP and MSAP Analysis of ‘Lane Late’ Navel Orange and Its Bud Sport Pumpkin-like Navel Orange

[Objectives]The paper was to analyze the differences of genes and genome methylation between‘lane late’navel orange and it’s bud sport pumpkin-like navel orange,and to reveal the causes of bud sport.[Methods]Amplification fragment length polymorphism(AFLP)and methylation sensitive amplification polymorphism(MSAP)were used to analyze the differences in genes and genome methylation of‘lane late’navel orange and its bud sport pumpkin-like navel orange.[Results]Gene mutation occurred between the‘lane late’navel orange and its bud sport pumpkin-like navel orange.A total of 15 differential bands were obtained by AFLP markers,and the percentage of polymorphic bands was 6.0000%.Meantime,10 differential bands were obtained by MSAP markers,and the percentage of polymorphic bands was 5.4645%.The semimethylation rate and permethylation rate of‘lane late’navel orange were higher than that of pumpkin-like navel orange,that is,pumpkin-like navel orange had demethylation(demethylation ratio was 1.6393%).[Conclusions]It is proved at the DNA level that the emergence of bud sport pumpkin-like navel orange is due to gene mutation,and the DNA methylation level of the bud sport material has also changed.This study lays a foundation for further exploring the mechanism of bud sport.

Effects of Wet Superfine Grinding on Polyphenols and Antioxidant Activities of Whole Fruit Pulp of Navel Orange

The navel orange were cleaned and pulverized by a wet superfine grinding and a broken wall cooking machine,then the navel orange whole fruit pulp were obtained by wet superfine grinding once,wet superfine grinding twice,and broken wall cooking machine processing.The particle size distribution,free polyphenols,bound polyphenols and antioxidant activity of whole fruit pulp prepared by the three kinds of pulverization methods were discussed.The results showed that the particle size distribution of the whole fruit pulp by wet superfine grinding was more concentrated compared with the broken-wall cooking machine processing,and the total phenols dissolution rate of the navel orange whole pulp was increased by 6.9%,and the total flavonoid dissolution rate was increased by 13.5%.The results also suggested that wet superfine grinding twice could improve 1,1-diphenyl-2-picrylhydrazyl(DPPH)free radical scavenging activity of polyphenols in the whole fruit pulp,wet superfine grinding once and wet superfine grinding twice also could obviously enhance the reducing power and iron reduction ability of polyphenols in the whole fruit pulp.In conclusion,wet superfine grinding could increase both the polyphenol content and antioxidant activity of navel orange whole fruit pulp,it can be used as a pretreatment processing method for preparing navel orange whole fruit pulp.

Interprovincial Comparison and Evaluation of Export Competitiveness of Gannan Navel Orange Based on 2011-2016 Data

China's orange export was mainly concentrated in Jiangxi,Guangxi,Guangdong,Yunnan,and Fujian.The annual output of Jiangxi Gannan navel orange ranks first in the whole China,but the export competitiveness is not very prominent.In view of this,this paper compared the regional market advantages,export performance,export growth rate and export price of Gannan navel orange between Yunnan,Guangxi,Guangdong and Fujian.Through comparative analysis,it discussed the main problems in the development of Gannan navel orange.On the basis of learning development experience of orange industry of Guangxi,Guangdong,Fujian,and Yunnan,it came up with recommendations for improving export competitiveness of Gannan navel orange.

Problems in Development of Gannan Navel Orange and Recommendations

The rapid development of Gannan navel orange industry has made it become a regional superior industry in China. However,with the rapid expansion of the planting scale,the market dilemma of " vast planting but low income" of navel orange growers is increasingly deteriorating,and Gannan navel orange industrial system is to be further transformed and upgraded. Taking the quality and marketing as the bottleneck of industrial development,this paper analyzed factors influencing these two aspects. It came up with recommendations,including building superior regions,improving industrial quality and safety,and stressing multi-dimensional marketing,relying on government,enterprises,scientific research institutions,colleges and universities,non-governmental organizations,and navel orange growers,to promote high efficient and sustainable development of Gannan navel orange industry.

The Study Results of F1 Generation of Washington Navel Orange Obtained Through Distant Hybridization

For a successful selection of citrus plants when mating with cultural forms through the method of distant hybridization it is necessary to choose a promising father component such as： a） a complex hybrid of inchangensis ＂Caucasus＂ obtained using hybrid citrange of American origin _ C. Kinokuni X C.ichanglemon, which gives an eatable lemon with a chemical composition similar to the normal lemon fruit and without any damage it can resist frost at -16 ℃ temperature and b） spontaneous mutations of trifoliata： #1 and #2 which are distinguished among trifoliata species. Their fruits don＇t contain or contain a small amount of the substances that deteriorate the taste： naringin, porcine and so on. They are characterized by high index of frost resistance. In the experiment when obtaining sexual hybrids of the Washington naval orange the above mentioned components were used and hybrid seedlings were obtained, which are distinguished according to their phenotypic hereditary features. Selected seedlings represent the best initial material for a successful future work.

Effects of Fertilizers with Different Proportions of N, P and K on Citrus Fruit Cracking

[Objective] The aim was to explore fertilizers with different proportions of N, P and K on citrus fruit cracking and to seek best treatment in preventing fruit cracking. [Method] Compound fertilizers with different proportions of N, P and K were prepared, supplemented by leaf fertilizers with varying mineral elements. [Result] It is proved the treatment II containing spring fertilizers （N：P2O5：K2O=20：10：10）, summer fertilizers （N：P2O5：K2O=16：8：16）, and leaf fertilizers with calcium nitrate solu- tion （0.5%） achieved the best prevention effects of fruit cracking. In the meantime, N-to-K ratio and N-to-Ca ratio were proved of positive correlation with cracked fruits, and the higher the ratios, the higher the proportion of cracked fruits, vice versa. On other hand, Ca-to-K ratio was of negative correlation with cracked fruits, and the higher the ratio, the lower the proportion of cracked fruits. [Conclusion] In practical production, fertilization should be conducted as per soil moisture content, tree growth, and seasons, in a balanced and comprehensive way.

Glycine functionalized activated carbon derived from navel orange peel for enhancement recovery of Gd(Ⅲ)

Glycine functionalized activated carbon adsorption material(NOPAC-GLY-X)was successfully prepared by one-step thermal decomposition using agricultural waste navel orange peel as a precursor.Through batch adsorption experiments,it is found that the adsorption performance of Gd(Ⅲ)on activated carbon can be significantly enhanced by glycine modification.The adsorption isotherms of the NOPACs conform to the Langmuir isotherm model,and the maximum adsorption capacity of the activated carbon sample NOPAC-Gly-60 is approximately 48.5 mg/g.The Gd(Ⅲ)adsorption capacity of navel orange peel activated carbon can be doubled after glycine modification,and the adsorption efficiency of gadolinium can reach99%at pH=7.The physicochemical properties of the prepared adsorbents were characterized by Brunauer-Emmett-Teller(BET),Fourier transform infrared spectroscopy(FTIR),elemental analysis(EA),and X-ray photoelectron spectroscopy(XPS).The characterization test shows that the specific surface area of the sample increases from 1121 to 1523 m^(2)/g,and the ratio of(N+O)/C increases from 10.8%to 30.0%by the glycine modification.After five cycles of adsorption-desorption,the adsorption capacity can still be maintained at 88%of the initial capacity.NOPAC-GLY-60 has excellent adsorption selectivity for Gd(Ⅲ).With the obvious advantages of simple synthesis steps and low cost,the activated carbon modification method adopted in this study has great application value in the field of rare earth adsorption and recovery.

Construction and Characterization of a cDNA Library from the Pulp of Cara Cara Navel Orange （Citrus sinensis Osbeck）

A cDNA library was constructed end characterized from the pulp of Cera Care navel orange （Citrus sinensis Osbeck） at different stages of ripening. Tittering results revealed that approximately 5.086×10^5 independent clones were included in this library. Electrophoresls gel results of 15 randomly selected clones revealed that the size of the insertion fragments ranged from 400 bp to 2 kb, with an average size of 900 bp. Sequencing results of 150 randomly picked clones showed that the recombination rate was 94%. During subsequent sequence analysis, 41 of 139 clones failed to be identified end the amino sequence of 71 clones shared less than 30% identity with related plants in GenBank. Of 27 clones whose amino sequences shared more than 60% identity with other related plants in GenBenk, 17 clones showed an 80% identity with the corresponding candidate genes of citrus. The clone recognized as the type Ⅲ metallothlonein-llke （MT） gene was observed to occur 13 tlmes, Indlcatlng that the protein may play an important role In frult development and rlpenlng.

Detection of pesticides on navel orange skin by surface-enhanced Raman spectroscopy coupled with Ag nanostructures

Residual pesticides such as phosmet and chlorpyrifos in fruit have become a public concern problem in recent years.In this study,surface-enhanced Raman spectroscopy(SERS)was used to detect and characterize pesticides extracted from navel orange surfaces.Silver colloid was prepared for getting the SERS of phosmet and chlorpyrifos.Enhanced Raman signals of phosmet over a concentration range of 5 mg/L to 30 mg/L and chlorpyrifos over a concentration range of 5 mg/L to 20 mg/L were acquired.Partial least squares(PLS)regression combined with different data preprocessing methods was used to develop quantitative models.With the second derivative data preprocessing,the best prediction model of phosmet pesticide was achieved with a correlation coefficient(r)of 0.852 and the root mean square error of prediction(RMSEP)of 5.177 mg/L.The best prediction model of chlorpyrifos pesticide was achieved with r of 0.843 and the RMSEP of 2.992 mg/L using the multiplicative scatter correction(MSC)and first derivative data preprocessing.This study indicated that SERS coupled with Ag nanostructures is a potential tool for analysis of phosmet and chlorpyrifos pesticide residues.

Preparation and chemical characterization of banana/orange composite wine

Banana/orange composite wine was brewed in the lab by liquid fermentation using angel yeast and lactic acid bacteria as the fermentation strains,and characterized by chemical analyses.It was found that the best ratio of banana juice to navel orange juice was 1:2,and the optimum alcohol fermentation parameters were as follows:28~30℃,22%initial sugar content,6%yeast,and 6 days of fermentation to reach an alcohol concentration of 11.63%v/v.The free amino acids in the composite wines were tested by automatic amino acid analyzer,and the flavor components of the composite wine were determined and analyzed by gas chromatography-mass spectrometry(GC-MS).Seven types of trace elements in the composite wine were measured by atomic absorption spectrometry.Results showed that there were 17 free amino acids,and their total concentration was up to 897.6 mg/L.A total of 16 key compounds were identified in the composite wine,11 of which were ester,4 of which were alcohols and 1 of which was acid.Magnesium,iron,copper and manganese elements were relatively rich in the wine,while lead was extremely low.