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）.

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.

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.

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.

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.

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.

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.

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）.

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.

Key Points of Ridge Cultivation of Lane Late Navel Orange

Ridge cultivation can effectively enhance soil permeability,promote root development and improve fruit quality. Based on the characteristics of Lane Late navel orange,this paper summarizes the technical points related to ridge cultivation and compares the effects of ridge cultivation and conventional cultivation on the growth,so as to provide guidance for better production practices.

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.

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.

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.

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.

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.

Fruit Set in Orange with Phytohormones and Its Relation to Endogenous Levels of GA3

This research work aims to contribute in increasing the fruit set in citrus, given its importance in determining fruit yield. The authors evaluated the effects of phytohormones （auxins, gibberellins and cytokinins） in the mooring and features of orange fruit in cultivars Washington navel and Thomson （Citrus sinensis （L.） Osb.）, The experiment was established in a split plot randomized complete block design with five treatments and four replications. Flower tissue samples were stored in liquid N until the extraction of gibberellins and the identification and quantification of GA3. The results showed statistically significant difference （P 〈 0.05） between treatments in the number of fruits retained 129 d after flowering and the percentage of final tie. GA3 content ranged, on a dry weight basis, from 1.66 mg＇g1 in the control to 20.79 mg.g-1 in the high dose. The mean dose （32.2 mg.L-1 auxins, gibberellins 32.2 mg L-1 and 83.2 mg.L-1 cytokinins） caused the largest increase in fruit set.

不同产地脐橙鲜汁主要品质差异分析

为比较不同产地脐橙果汁品质差异,以赣南脐橙等8个不同产地的脐橙果汁为研究对象,比较橙汁样品间感官品质、理化指标、抗氧化活性、游离氨基酸、有机酸、挥发性风味物质等差异,并基于挥发性风味物质含量进行聚类分析(CA)。结果表明,感官检验显示,赣南脐橙整体接受度较好;理化指标检测表明,三凤脐橙褐变指数、浊度及氨基酸态氮含量较高,崇左脐橙L^(*)值、b^(*)值和可溶性固形物含量(SSC)较高;抗氧化活性测定结果表明,崇左脐橙维生素C(VC)(34.8 mg/100 mL)、总酚含量(850 mg/g)及总抗氧化能力(166.5 U/mL)较高;8种橙汁样品共检测出16种游离氨基酸,包括7种必需氨基酸,其中脯氨酸含量相对较高;共检出5种有机酸,以柠檬酸含量较高;共鉴定出53种挥发性风味物质,CA结果表明,基于挥发性风味物质含量可将样品分为三个大类,其中三凤脐橙和开州脐橙相似度较高。由此可知,不同产地脐橙汁品质有一定差异,赣南脐橙汁感官品质最佳,崇左脐橙果汁总抗氧化能力最强。

多粘类芽孢杆菌发酵液对脐橙果树内生菌的抑菌研究

目的:验证一种多粘芽孢杆菌发酵液对脐橙果树内生菌抑制特性,为筛选治理黄龙病的药物奠定基础。方法:纯化培养黄龙病果树内生菌,经16S rDNA鉴定菌属,选择和黄龙病菌有相关性的内生菌为药敏实验菌株,以青霉素G、四环素、利福平、链霉素、吡哌酸、氨苄西林和多粘类芽孢杆菌发酵液为对比抑菌药物,分析抑菌差异以便筛选合适的内生菌抑菌药物。结果:分离获得黄龙病菌的相关性内生菌6株,药敏实验发现链霉素对所有菌株无药敏,青霉素G、利福平、氨苄西林对细杆菌属具有高药敏性,四环素对代尔夫特菌属和不动杆菌属具有高药敏性,发酵液对代尔夫特菌属和伯克霍尔德菌属具有高的药敏性,其中,利福平对所有菌株均有药敏性,四环素仅对伯克霍尔德菌属无药敏性。结论:多粘类芽孢杆菌发酵液对黄龙病果树内生菌有优良的抑制效果。

赣南脐橙出口贸易现状及影响因素研究

“中华名果”赣南脐橙作为全国十一大优势农产品之一,是江西省唯一入围商务部、中欧地理标志协定谈判的地理标志产品,也是江西省主要出口农产品之一。但近年来,赣南脐橙呈现出口规模下降、出口数量小、出口种类形式单一、出口价格低和出口市场分布较为集中等问题。加工能力差、品种单一、安全品质不高、物流发展滞后、品牌意识薄弱、营销水平滞后等是影响赣南脐橙出口贸易的主要因素。为了促进赣南脐橙出口可持续发展,应提高加工水平和出口附加值,提升出口品质和优化品种结构,加强脐橙品牌管理和提高营销水平,以及完善基础设施并出台便利政策。