基于YOLOv7改进的夜间樱桃检测方法:YOLOv7-Cherry

针对樱桃检测算法无法对夜晚环境下的樱桃进行成熟度识别的问题,提出一种改进的YOLOv7算法:YOLOv7-Cherry。使用一种将夜间樱桃图像和白天相同位置的樱桃图像相融合的图像预处理方法,保留夜间樱桃图像高空间分辨信息的同时加强其光谱分辨率。在YOLOv7-Cherry中,将CBAM注意力机制插入到骨干网络中,利用注意力机制强化神经网络的表征能力,强调重要特征,忽略次要特征,加强对樱桃目标特征的提取;为了加强目标检测算法对图像中小樱桃的识别,增加小目标检测层;改进了原始网络的初始检测框大小;为了减少遮挡对樱桃目标造成的损失,对检测框使用了Soft-NMS方法进行冗余去除。实验结果表明,YOLOv7-Cherry可以有效地识别出夜晚环境下的成熟樱桃和未成熟樱桃,与YOLOv3、Faster-RCNN、YOLOv4、YOLOv5和原YOLOv7相比,YOLOv7-Cherry的mAP提高了26.88、25.05、22.51、17.11和7.66个百分点,其中,识别精度、召回率、mAP和F1为93.9%、94.7%、97.4%、94.3%。

Analysis on Genetic Diversity of 40 Flowering Cherry Cultivars and Construction of Molecular ID Based on SSR Markers

Studying on the genetic diversity and genetic relationship of flowering cherry cultivars is extremely important for germplasm conservation, cultivar identification and breeding. Flowering cherry is widely cultivated as an important woody ornamental plant in worldwide, especially Japan, China. However, owning to the morphological similarity, many cultivars are distinguished hardly in non-flowering season. Here, we evaluated the genetic diversity and genetic relationship of 40 flowering cherry cultivars, which are mainly cultivated in China. We selected 13 polymorphicprimers to amplify to allele fragments with fluorescent-labeled capillary electrophoresis technology. The population structure analysis results show that these cultivars could be divided into 4 subpopulations. At the population level, Na and Ne were 6.062, 4.326, respectively. Ho and He were 0.458 and 0.670, respectively. The Shannon’s information index (I) was 1.417. The Pop3, which originated from P. serrulata, had the highest Ho, He, and I among the 4 subpopulations. AMOVA showed that only 4% of genetic variation came from populations, the 39% variation came from individuals and 57% (p < 0.05) came from intra-individuals. 5 polymorphic SSR primers were selected to construct molecular ID code system of these cultivars. This analysis on the genetic diversity and relationship of the 40 flowering cherry cultivars will help to insight into the genetic background, relationship of these flowering cherry cultivars and promote to identify similar cultivars.

Effect of Weak Light on the Peroxidation of Membrane_Lipid of Cherry Leaves

The effect of weak light on the peroxidation of membrane_lipid of one_year_old cherries ( Prunus pseudocerasus L. 'Laiyang') was studied by whole_tree shading. The results showed that the net photosynthetic rate of cherry leaves under weak light was remarkably lower; the activity peroxidase (POD) increased when light intensity decreased; the activity of catalase (CAT) showed an opposite trend, and it was positively correlated with light intensity; the activity of superoxide dismutase (SOD) increased under 366 μmol·m -2 ·s -1 and 533.8 μmol·m -2 ·s -1 light intensity, but decreased under 228.8 μmol·m -2 ·s -1 and 83.9 μmol·m -2 ·s -1 light intensity. A remarkable increase of malondialdehyde (MDA), a product of membrane_lipid peroxidation, was also observed in cherry leaves when treated with weak light, indicating more serious peroxidation in the membrane.

Effects of Probiotics on Growth Performance and Blood Biochemical Indexes of Cherry Valley Ducks

In order to investigate the effects of probiotics on growth performance, blood biochemical indexes and economic benefits of Cherry Valley ducks, different probiotics were added into the feed of Cherry Valley ducks. Total 240 1-d-old Cherry Valley ducks were selected, and they were randomly divided into 4 groups, including 1 control group and 3 treatment groups. There were 3 replicates for each group and there were 20 ducks for each replicate. The ducks in the control group were fed the basal diet, and the ducks in the 3 treatment groups were fed the basal diet added with Lactobacillus, Bacillus natto and florfenicol, respectively. The test lasted for 42 d. The results showed that the addition of Lactobacillus and Bacillus natto could improve the average daily weight gain and final average weight （P〈0.05） of Cherry Valley ducks, and reduce the glutamic-pyruvic transaminase ac- tivity, alkaline phosphatase activity and serum urinary nitrogen content in duck blood （P〈0.05） and reduce the creatinine content and total cholesterol content in Cherry Valley ducks （P〉0.05）; at the same time, adding probiotics to feed could also in- crease the grass economic benefits of Cherry Valley ducks. In overall, the effects of adding probiotics were better than those of adding antibiotic.

Effects of Controlled Atmospheres with High_O_2 or High_CO_2 Concentrations on Postharvest Physiology and Storability of "Napoleon" Sweet Cherry

Sweet cherries ( Prunus avium L. cv. Napoleon) were stored in controlled atmospheres (CA) of high O(2) (70% O(2) + 0% CO(2)) or high CO(2) (5% O(2) + 10% CO(2)), in modified atmosphere package (MAP, (13% - 18%) O(2) + (2% -4%) CO(2)) and in air (control) at 1 degreesC to investigate the effects of different O(2) and CO(2) concentrations on physiological properties, quality and storability of the fruits during storage. The results indicated that compared with other treatments, CA with high O(2) concentration decreased fruit decay and ethanol content, but increased the accumulation of malondialdehyde (MDA) and stimulated browning. CA with high CO(2) concentration inhibited polyphenol oxidase (PPO) activity, reduced MDA content, maintained vitamin C content and firmness, decreased fruit decay and browning. Soluble solids contents (SSC) were not significantly affected by different atmosphere treatments. 'Napoleon' fruits stored in 5% O(2) + 10% CO(2) for as long as 80 d were of good quality, but only 40, 20 and 30 d stored in MAP, 70% O(2) + 0% CO(2) and air, re-spectively.

Effects of Different Preservative Treatments on Physiological Metabolism and Preservation of Sweet Cherry

[Objective] This study aimed to investigate the effects of different preservative treatments on physiological metabolism and preservation of sweet cherry. [Method] Sweet cherry （Prunus avium var. Summit） was soaked into benziothiazolinone （1 000 ppm）, lysozyme （500 ppm）, lysozyme （500 ppm） ＋ NPS polysaccharide （5 000 ppm） and water for 5 min, respectively. Non-treated sweet cherry was set as control. All the sweet cherries were then put into 3 mm thick PE bags and preserved at （-0.5±0.5） ℃. [Result] The results showed that the malate dehydrogenase （MDH） activity of benziothiazolinone treatment researched a significant peak on the 14 th d, while the MDH activity of Lysozyme （500 ppm）, Lysozyme （500 ppm） ＋ NPS polysaccharide （5 000 ppm） and water treatments began to increase on the 20 th d; the polyphenol oxidase （PPO） activity in various treatments showed a decreasing trend during the experiment, which researched a significant peak on the 14 th d, while that in water treatment was decreased consistently; on the 21 st d, the PPO activity in each treatment increased slowly; the titratable acid （TA） content in preservative treatments was higher than that in both water treatment and control; the soluble solid （SSC） content showed no significant difference between various treatments and between experimental treatment and control; on the 40 th d, the healthy fruit rate in preservative treatments was significantly higher than that in water treatment and control. [Conclusion] Benziothiazolinone, lysozyme and other preservatives show good effects on preservation of sweet cherry; lysozyme treatment can decrease the activity of malate dehydrogenase, maintain the relatively high content of organic acid and significantly improve the healthy fruit rate within a certain period of time.

Application of Landfill Composed of Biogas Residue and Slurry in Cherry Production

In order to explore the effects of landfill composed of biogas residue and slurry on the improvement of soil nutrients and cherry fruit yield, three treatments： control （no landfill）, landfilling with biogas residue and water （BR）, landfilling with biogas residue and slurry （BS） were conducted in a cherry orchard. The results showed that compared with the control, soil water content around the landfills with a radius of 60 cm within 30 d was increased in BR and BS treatments. The poment- age of short shoots and the total number of shoots of cherry trees were also signif- icantly increased by BR and BS treatments; the cherry fruit yield per tree and the single-fruit weight in BS treatment were increased by 21.76% and 28.89%, respec- tively. In addition, BS treatment obviously improved the contents of soil organic matter, soil available nitrogen, s0il available phosphorus, soil available potassium and other nutrients. The positive effects of BR treatment on the improvement of soil nutrients and cherry fruit yield were lower than those of BS treatment, indicating that the combined use of biogas residue and biogas slurry as landfill can improve the soil water and fertilizer status in orchards, and thus can be promoted in the cultivation of fruit trees.

Cluster Analysis of Characteristics of Different Sweet Cherry Varieties

In order to compare the characteristics of different varieties of sweet cherry and to formulate corresponding pruning scheme, hierarchical cluster analysis was conducted for the 14 sweet cherry varieties that were mainly planted in Shanxi Province. The results showed that the 14 varieties of sweet cherry could be divided into two types, Hongmanao and Rainier. Fruit setting rate, branching rate, medium fruit shoot proportion, spur proportion and yield per plant were significantly different between these two types of sweet cherry. The key points of pruning management, to improve the yield of Rainier type, were to increase the fruit setting rate and spur proportion, and to control properly the long and medium fruit shoot proportion.

Study on Chilling Requirement of Different Fruit Branch of a Sweet Cherry Cultivar ‘Hongmanao'

With ＇Hongmanao＇, a sweet cherry cultivar from central Shanxi Province, as the experimental material, the chilling requirements of different types of fruit branches （including mixed fruit branch, long fruit branch, medium fruit branch, short fruit branch and blossom fruit branch） were studied by the 0-7.2 ℃ model in a solar greenhouse during 2012-2013. In the greenhouse, the fruit branches of ＇Hongmanao＇ were cultured in water in a thermostatic environment. The results showed that the chilling requirement of leaf buds of ＇Hongmanao＇ was lower than that of its flower buds; and the chilling requirements of the five types of fruit branches ranked as blossom fruit branch＇s〈short fruit branch＇s〈medium fruit branch＇s〈long fruit branch＇s〈mixed fruit branch＇s,

Interaction Between Cryptococcus laurentii,Monilinia fructicola,and Sweet Cherry Fruit at Different Temperatures

The present study was performed mainly to investigate the antagonist-pathogen-host interaction in wounds of the sweet cherry fruits. The antagonistic yeast Cryptococcus laurentii could significantly reduce the brown rot of the sweet cherry fruit caused by Monilinia fructicola at 25 and 1 ℃. The populations of yeast increased faster in the presence of the pathogen initially, but then decreased rapidly. In the fruits inoculated with M. fructicola alone or combined with C. laurentii, an induction of lipid peroxidation as well as activities of the antioxidant enzymes, such as, superoxide dismutases （SOD）, catalase （CAT）, and peroxidase （POD）, was observed. The isoenzyme pattern of polypheno/oxidase （PPO） changed greatly after the symptoms appeared, with new PPO isoforms being induced. By contrast, the induction of lipid peroxidation and activities of SOD, CAT, and POD were low, although no significant changes were found in the PPO isoenzyms in the fruits inoculated with antagonist C. laurentii alone. The inhibition of brown rot during the antagonist- pathogen-host interaction in wounds of the sweet cherry fruits was mainly on account of the stimulated growth of C. laurentii as well as the induction of antioxidant enzymes of the fruits by M. fructicola.

腺相关病毒AAV2/8-CaMKIIα-ChR2-mCherry的组织学及通道功能鉴定

目的对腺相关病毒AAV2/8-Ca MKIIα-ChR2-m Cherry在大鼠内侧前额叶谷氨酸能神经元中表达的组织学及通道功能予以鉴定。方法以立体定位注射技术将腺相关病毒AAV2/8-Ca MKIIα-ChR2-m Cherry注射到SD雄性大鼠内侧前额叶,当病毒注射3~4周后,采用免疫荧光组织化学技术检测标记蛋白（m Cherry）在谷氨酸能神经元（特异启动子Ca MKIIα）的表达情况;利用在体细胞外记录技术观测谷氨酸能神经元所表达的通道蛋白（ChR2）对不同光刺激频率的电生理反应特性。结果病毒成功注射到内侧前额叶并特异表达通道蛋白于谷氨酸能神经元的细胞膜上,表达成功率为（94.6±0.9）%;表达ChR2通道蛋白的谷氨酸能神经元对蓝光（470 nm,20 m W/mm2,5 ms波宽,5~80 Hz）产生稳定的光激活反应,并且对低频光刺激（5、10、20 Hz）的反应性优于高频光刺激（40 Hz和80 Hz;P〈0.001）。结论腺相关病毒AAV2/8-Ca MKIIα-ChR2-m Cherry能成功表达在谷氨酸能神经元的细胞膜上,对光刺激有频率选择性。

Changes of Aroma Components in Hongdeng Sweet Cherry During Fruit Development

To study the changes of aroma components in sweet cherry during fruit development, the aroma components in sweet cherry fruit from the green stage, the color stage, the commercial stage, and the ripe stage were collected using head-space solid phase microextraction （HS-SPME）, and were analyzed using a gas chromatograph-mass spectrophotometer （GC- MS）. A total of 37 compounds were identified from the sample extracts. Aldehydes, alcohols, and esters were the major constituents. The aroma components behaved differently during the fruit developmental period. C6 aldehydes and aromatic aldehydes were the main aldehydes in the sweet cherry fruit. The contents of C6 aldehydes increased quickly to 84.16% in the color stage, then decreased as ripening proceeded, and then, the contents decreased to 59.20 and 55.58% at the commercial stage and the ripe stage, respectively. The aromatic aldehydes （benzaldehyde） increased as ripening proceeded, and the maximum was found at the ripe stage. Alcohols of sweet cherry fruit included C6 alcohols and aromatic alcohols. The content of （E）-2-hexen-l-ol increased as ripening proceeded. The maximum was found at the commercial stage; alcohol was only found at the ripe stage. Ester components included ethyl acetate, butanoic acid ethyl ester, hexanoic acid ethyl ester, which increased as the fruit ripened. Hexanal, （E）-2-hexenal, benzaldehyde, （E）-2-hexen-l-ol, ethyl acetate, and hexanoic acid ethyl ester were the characteristic aroma components of sweet cherry fruit. These aroma components started to form drastically at the color stage, and the main aroma was formed at the commercial stage, which then turned bad at the ripe stage because of the presence of alcohol. So the optimal harvest time of sweet cherry was at the commercial stage.

Reduction of Chilling Injury and Ultrastructural Damage in Cherry Tomato Fruits After Hot Water Treatment

The effects of hot water treatment in alleviating chilling injury and reducing ultrastructural damage of mature-green cherry tomatoes （Lycopersicun esculentum cv. cerasiform Alef） were investigated. Mature-green cherry tomato fruits were treated in water at 40℃ or 45℃ for 5 min or 15 min, and then stored at 5℃ for 19 days followed by ripening at 20℃. Water treatment at 40℃ for 15 min increased tolerance of cherry tomato fruits to chilling stress, indicating as low outbreak of skin lesion, high color a＊ value, and low electrolyte leakage. Treated fruits showed typical climacteric respiration and developed normal red color with chlorophyll degradation and lycopene accumulation during ripening, while fruits without treatment failed to develop red color and suffered skin lesion. After 19 days of chilling, heated fruits showed the conversion of chloroplast to chromoplast with the disappearance of thylakoids. Mitochondria and other cell organelles were not adversely affected in treated fruits. However, ultrastructures in pericarp cells in control fruits severely damaged with extensive disorganization of cytoplasm, swelled chloroplasts, distorted and unstacked thylakoids. Chloroplast was the first and most severely impacted organelle by chilling stress. Hot water treatment （40℃ for 15 min） before storage alleviated chilling injury in cherry tomato fruits. The results suggest that chilling injury is related with the damage of cell structure under chilling stress.

Flavonoid content and radical scavenging activity in fruits of Chinese dwarf cherry(Cerasus humilis) genotypes

The Chinese dwarf cherry（Cerasus humilis（Bge.） Sok.） is a small shrub with edible fruits. It is native to northern and western China. This species was included as a medicinal plant in the ‘‘Chinese Pharmacopeia’’ and has emerged as an economically important crop for fresh fruit consumption, processing into juice and wine and nutraceutical products as well. To gain a better understanding of flavonoid biosynthesis and help develop value added products and better cultivars with greater health benefits, we analyzed total flavonoid content（TFC）, composition, and radical scavenging activities in fruit extracts of 16 Chinese dwarf cherry genotypes. Fruit peel TFC ranged from 33.5 to72.8 mg/g REáFW（RE： rutin equivalent, FW： fresh weight）while fruit flesh TFC ranged from 4.3 to 16.9 mg/g REáFW.An HPLC analysis revealed that fruit extracts contained 14 flavonoids with considerable variation in their profiles across genotypes. The most abundant flavonoids in most genotypes were proanthocyanidin B1（PA-B1）, proanthocyanidin B2（PA-B2）, phloretin 20-O-glucoside（PG）, and phloretin 20,40-O-diglucoside（PDG）. Principal component analysis showed that PG, PA-B1, and PA-B2 had large,positive factor loading values in the first principal component for each genotype. Increased scavenging activity of2,2-diphenyl-1-picrylhydrazyl（DPPH） radicals was apparent in genotypes ‘Nongda 4’, ‘Nongda 3’, ‘Nongda 6’,‘Wenfenli’, and ’10-32’, suggesting promising applications in the production of nutraceutical products. In summary, our results will aid in breeding, fruit processing, and developing medicinal uses of the Chinese dwarf cherry.

Impact of chilling accumulation and hydrogen cyanamide on floral organ development of sweet cherry in a warm region

The microscopic investigation of the floral development of sweet cherry（Prunus avium L. cv. Hongdeng） from a warm winter climate（Shanghai） and cold winter climate（Tai＇an, Shandong Province, China） was conducted to explore the reason of low fruit set. The effect of hydrogen cyanamide（HCN） on floral development under warm winter conditions was also investigated. Trees grown in Shanghai with insufficient chilling accumulation exhibited little difference in the progression of microspore development compared to trees in Tai＇an that accumulated adequate chilling, but showed substantial delays in ovule and embryo sac development. The growth of nucelli did not proceed beyond the macrospore mother cell and macrospore stages with abortion rates of 13, 15 and 45% by 6, 3 and 0 d before full bloom, respectively. These abnormalities in the ovule and embryo sac in the Shanghai-grown trees were eliminated by HCN application. These results suggest that chilling regulates the development of female floral organs in winter dormancy; therefore, insufficient chilling accumulation, causing abnormality of the female floral organs, restricts the cultivation of sweet cherry in warm winter regions. Interestingly, HCN application, which decreased the chilling requirements for Hongdeng, may be a potential strategy for sweet cherry cultivation in warm winter regions.

Regeneration of Leaves in vitro in Cherry Rootstock Colt

Plants were regenerated from leaves of cherry rootstock Colt by two methods,the frequencies were 48 3% and 21 3%.Leaves were cultured on MS medium supplemented with NAA 1 0mg/L,KT 3 0mg/L and ZT 0 25mg/L.After 5～7 days leaves dedifferentiated,and formed callus.About 25 days later,callus grew into greenish or pink compact ones,the induction frequency was 100%.The color and structural feature of callus depended on the medium,culture condition and physiology phase of leaves.To induce callus,NAA was the main factor.Leaves rooted in medium only with NAA.In order to inhibit rooting and make callus grow fast,KT and ZT were added to the medium.Leaves cultured without light could quickly form callus during the initial stage of dedifferentiation.Young leaves dedifferentiated more easily than old leaves.After had been cultured about 50 days,callus were transferred to MS medium supplemented with NAA 0 2mg/L,IAA 0 5mg/L,6 BA 0 5mg/L,KT 1 0 mg/L and GA 0 5mg/L,and redifferentiated at a frequency of 21 3%.The callus of Colt leaves were difficult to redifferentiate.GA was important in the redifferentiation of callus.The result showed that callus could redifferentiate in all the mediums with GA,and could not redifferentiate without GA.The ability of redifferentiation of big callus was higher than that of small ones.And the physiology character of callus was also important.High regeneration frequency was obtained from greenish or pink compact callus.The frequency of regeneration of petioles was higher than that of leaves.Leaf petioles' regeneration need high concentration of cytokinin(more than 5 0mg/L).Leaf petioles were cultured on MS medium supplement with 6 BA 6 0mg/L,NAA 1 0mg/L and GA 0 5mg/L,and regenerated at a frequency of 48 3%.

Wudang cherry ameliorates urate underexcretion and renal dysfunction in hyperuricemic mice

OBJECTIVE To investigate effects of Wudang cherry on urate excretion and renal function and examined whether renal organic ion transporters were involved in potassium oxonateinduced hyperuricemic mice.METHODS The model of hyperuricemic mice was induced by intraperitoneal injection of potassium oxonate(250 mg·kg^(-1))for 7 d.Water extracts of Wudang cherry at 500 mg·kg^(-1)were orally administered to hyperuricemic mice for 7 d,benzbromarone(20 mg·kg^(-1))and allopurinol(20 mg·kg^(-1))were given as positive controls,vehicle control group was given equal normal saline.Serum and urine levels of uric acid were measured in hyperuricemic and normal mice.Simultaneously,the m RNA and protein levels of mouse urate transporter 1(m URAT1),glucose transporter 9(mGLUT9),organic anion transporters(mOAT1 and mOAT3),ATP-binding cassette,subfamily G,membrane 2(mABCG2)and organic cation/carnitine transporters(m OCT1,m OCT2,m OCTN1 and m OCTN2)in the kidney were analyzed by Western blot,RT-PCR,immunohistochemical and immunofluorescent assay,respectively.RESULTS Wudang cherry significantly reduced serum uric acid levels and increased urine uric acid levels in hyperuricemic mice.And it effectively reversed potassium oxonate-induced alterations in renal m URAT1,mGLUT9,mOAT1,mOAT3 and mABCG2 m RNA and protein levels,resulting in the enhancement of renal urate excretion in mice.Moreover,Wudang Cherry increased renal m OCT1,m OCT2,m OCTN1 and m OCTN2 m RNA and protein levels,and improved renal impairment in this model.CONCLUSION Wudang cherry processes uricosuric and nephroprotective actions by regulating renal organic ion transporters in hyperuricemic mice.

Plant profile,phytochemistry and pharmacology of Cordia dichotoma(Indian cherry):A review

More than half of the world's population relies on the traditional medicine and major role of the traditional medicine including the use of plant extract and their active constituents.Among them,Cordia dichotoma Forst.,a small to moderate size plant of family Boragenaceae.commonly called bhokar,lasura,gonda,Indian cherry and shlesmataka.Plant parts such as leaves,fruit,bark and seed have been reported for possessing antidiabetic,antiulcer,anti-inflammatory,immune-modulator and analgesic activity.Screening of fruit,leaves and seed shows the presence of pyrrolizidine alkaloids,coumarins,flavonoids,saponins,lerpenes and sterols.Present review focuses on details of geographical distribution,physicochemical parameters,phytoconstituents and pharmacological properties of Cordia dichotoma reported so far.

Effects of Different Atmospheres on the Postharvest Physiology and Quality of the Sweet Cherry

The changes in physiological characteristics, quality and storability of the sweet cherry (Pru-mus avium L. cv. Hongdeng) stored in controlled atmospheres (CA), in modified atmosphere packages (MAP) and in air (CK) were investigated in this paper. The results showed that CA and MAP treatments significantly inhibited fruit rot and flesh browning, kept firmness and fruit color, reduced ethylene and ethanol content in pulp, slowed down the increase of polyphenol oxidase (PPO) and peroxidase (POD) activity and malondialdehyde (MDA) content in comparison with CK. Meanwhile, CA treatments showed a better benefit of reducing ethylene and ethanol contents, inhibiting PPO and POD activities, declining rot rate and browning index compared to MAP. The fruit could be stored in CA conditions for 60 days without any off-flavor. The sweet cherries kept in CA with 5% O2 + 10% CO2 showed a better storability than that in CA with 5% O2 + 5% CO2.

Complete Genome Sequence Analysis of Duck Circovirus Strains from Cherry Valley Duck

To investigate molecular epidemiology of DuCV in Cherry Valley ducks in China, the complete genomes of six DuCV strains, which were detected from Cherry Valley ducks in China between 2007 and 2008, were sequenced. Sequence and phylogenetic analysis were carried out to compare these six strains with another 27 DuCV strains from Mulard duck, Muscovy duck, Pekin ducks and Mule duck. The analysis showed that the six DuCV strains exhibited typical genetic features of the family of DuCV, such as a stem-loop structure, three major open reading frames (Rep, Cap and ORF3), four intergenic repeats and the conserved motifs for rolling circle replication and for the dNTP binding domain located in the Rep protein. Phylogenetic analysis of the nucleotide sequences of the complete genome and Cap gene of these strains together with those that have been previously published demonstrated two distinct DuCV genotypes. The DuCV strains with complete genomes containing 1988 and 1989 nucleotides clustered in genotype A, whereas the strains with complete genomes containing 1991, 1992, 1995 and 1996 nucleotides lay in genotype B. The six DuCV strains from Cherry Valley ducks were divided into the two groups. The results of the study provides some insight into the variation of DuCVs in Cherry Valley ducks.