Cherry Production Research Articles

Quality Attribute-Price Relationship: Modernization of the Sweet Cherry Sector in Poland

This study describes the development of sweet cherry production in Poland in the context of relationship between quality attributes and wholesale prices as well as modernization of orchards creating opportunities for increased exports. Global demand for sweet cherries increases because of their perceived unique health benefits, but the fruit must have the desired quality attributes. The link between quality attributes and prices is illustrated using the wholesale prices collected during the harvest season in years of limited and normal crop in Poland, respectively. Among the discussed varieties is ‘Cordia’ which dominates in the modern orchards. As the sweet cherry production declines in the region, with the introduction of modern production technology, the increasing yields and volume produced creates opportunities for increased exports also to countries outside the EU.

Association between the concentration of n-alkanes and tolerance to cracking in commercial varieties of sweet cherry fruits

Fruit cracking is one of the major economic losses in cherry production worldwide. Factors involved in differential tolerance among varieties are unknown. This phenomenon is mainly caused by rainfall during the harvest period and is related to osmotic factors and fruit water permeability. The cuticle is a hydrophobic extracellular membrane and soluble waxes represent a mixture of aliphatic very long chain fatty acids, its derivatives and cyclic compounds like triterpenes. Analysis of waxes from enzymatic isolated sweet cherry fruit cuticles showed that the main components are triterpenes (76%), alkanes (19%) and alcohols (1%).Cracking in vitro was investigated in five sweet cherry varieties. After removal of cuticular wax fruit cracking was significantly increased. Nuclear magnetic resonance analysis (1H and 13C NMR), revealed that fruits of different sweet cherry varieties contain primarily n-alkane with 29 carbons and no iso-alkane. Gas chromatography–mass spectrometry (GC–MS) enabled identification and quantification of n-alkanes. Varieties with significantly higher concentrations of nonacosane (Kordia, Regina and Lapins) were more tolerant to cracking compared to varieties with lower amounts (Bing and Rainier).We hypothesized that there is an association between the amount of C 29 n-alkane and cracking tolerance in sweet cherry fruits. This difference could be an important factor to explain the different tolerances to cracking in fruits of sweet cherry varieties.

Impact of packaging material and storage conditions on polyphenol stability, colour and sensory characteristics of freeze-dried sour cherry (prunus cerasus var. Marasca).

The aim of this study was to evaluate the influence of packaging materials and storage conditions on polyphenols stability, colour and sensory characteristics of freeze-dried sour cherry (Prunus cerasus var. Marasca). Freeze-dried sour cherries were packed in high barrier metalized polypropylene and aluminium packaging (PET/PPmet/PE and PET/Al/PE) for up to 12months at 4, 20 and 37°C. Characterisation of polyphenol compounds was done by HPLC UV/Vis PDA and in all samples individual anthocyanins (ANTs), flavonol-glycosides (FGs) and hydroxycinnamic acids (HCAs) were determined. Polyphenol content was not markedly affected by freeze-drying and decreases were amounted 1.5-5%. Furthermore, obtained results indicated that minimal loss of polyphenol content in freeze dried sour cherries were achieved at 4°C and 3months of storage. Regardless of the type of packaging materials, samples stored at lower temperature during 12months, retained the higher content of FGs (quercetin-3-glucoside, kaempferol-3-glucoside, kaempferol-3-rutinoside) and HCAs (neochlorogenic, chlorogenic, p-coumaric, caffeic and ferulic acid) than ANTs (cyanidin-3-glucosylrutinoside, cyanidin-3-rutinoside, cyanidin-3-glucoside, cyanidin-3-sophoroside). The same trend was confirmed with kinetic parameters, also. Sour cherry products packed in both type of laminate and stored at lower temperature retained characteristic dark red colour and sensory properties. This study showed that freeze-dried cherry products have pleasant sensory and very good nutritional properties, and storage in both type of laminates at 4 and 20°C up to 6months ensured good product quality.

Genetic diversity and pathogenicity of Monilinia polystroma – the new pathogen of cherries

Brown rot caused by fungi belonging to the genus Monilinia is one of the major limiting factors of sour and sweet cherry production. Up to now, three species, M. fructigena, M. laxa and M. fructicola, have been identified as causal agents of brown rot on cherries worldwide. From 2010 to 2013, during the monitoring of cherry orchards in different areas of Poland, a fourth species, M. polystroma, was isolated from brown rot symptoms on sour and sweet cherry fruits. To the best of the authors’ knowledge, this is the first time M. polystroma has been reported as the causal agent of brown rot on cherries. The genetic diversity of M. polystroma isolates from cherries and other hosts was analysed using PCR MP, ISSR and RAPD techniques and showed its clear distinctness from other Monilinia spp. tested. The cluster analysis of fingerprinting data revealed a high similarity of M. polystroma isolates from Poland and their close relationship with the reference strain from Japan, indicating that this species is a recently introduced pathogen. The highest genetic distance between the examined isolates and the highest number of different genotypes was observed in an ISSR assay. Detailed genetic diversity characteristics revealed that M. polystroma isolates from cherries did not create a distinct group but were intermingled with M. polystroma isolates from other hosts. The results of the pathogenicity test conducted on different fruit species indicated a lack of host specificity for M. polystroma isolates.

Flower development in sweet cherry framed in the BBCH scale

In recent years, a growing interest to widen the cherry (Prunus avium L.) production calendar results in cultivation out of the traditional cultivation areas. Since cherry has high chilling requirements, this often causes erratic cropping related to phenological alterations. However, appropriate phenological characterisation and comparison is hampered, due to the lack of a consensus phenological scale for this species. In this work, we have characterised flower development in sweet cherry, framing it in the BBCH scale. For this purpose, the phenology of two cherry cultivars has been characterized over 2 consecutive years and adapted to the BBCH code, and flower development has been framed within the principal growth stages of this code. This provides a unified standardised approach for phenological comparative studies.

Color and Bioactive Compounds Characteristics on Dehydrated Sweet Cherry Products

It is widely known that quality properties of fruits can be affected by drying processes. The approach was the quality improvement of dried cherry products through the application of combined technologies of drying and pretreatments. The objective of this work was to analyze the effect of blanching or sugar infusion prior to air-drying or freeze-drying on quality properties such as color, bioactive compounds, and antiradical power of two cherry products (discs and dices). Air-drying caused darkening, whereas freeze-drying provoked higher lightness of discs compared to fresh fruit (p < 0.05). Cherry dices were lighter than the fresh fruit. A high retention of total anthocyanin (ACY) and phenolic content (TPC) was obtained in blanched freeze-dried discs (ACY = 165 ± 22 mg Cyd-3-glu/100 g d.w.; TPC = 739 ± 55 mg GAE/100 g d.w.). Sugar infusion pretreatment caused an important decrease in ACY (31–89 mg Cyd-3-glu/100 g d.w.) and TPC (222–271 mg GAE/100 g d.w.). When blanching was applied prior to air-drying, samples presented the highest antiradical power, similar to that observed in fresh fruit. In dices, the best quality attributes in terms of superficial color were found in control freeze-dried samples since they presented minor shifts in hue angle and a greater preservation of anthocyanin pigments (ACY = 211 ± 30 mg Cyd-3-glu/100 g d.w.). However, control air-dried dices presented the highest phenolic content (TPC = 771 ± 65 mg GAE/100 g d.w.). Regarding the possible application of the dry cherry products, discs could be directly consumed as snacks, while dices could be incorporated as ingredients in fruit bars, cookies, or muffins.

INCIDENCE OF SWEET CHERRY VIRUSES IN SHANDONG PROVINCE, CHINA AND A CASE STUDY ON MULTIPLE INFECTION WITH FIVE VIRUSES

Leaves were collected from a total of 62 trees displaying virus-like disease symptoms such as rugose mosaic in leaf, irregular shaped leaf blades or small leaf blades in a survey of sweet cherry (Prunus avium L. cv Red Lamp) in Shandong Province, the largest cherry production area in China. Reverse transcription-polymerase chain reaction (RT-PCR) analysis indicated that Prunus necrotic ringspot virus (PNRSV), Prune dwarf virus (PDV), Little cherry virus- 2 (LChV-2), Cherry virus A (CVA) and Cherry green ring mottle virus (CGRMV) were present and that most of the samples (70%) were infected by at least two viruses. A case study in this survey of two selected trees revealed that a mixed infection with these five viruses simultaneously caused two types of field symptoms: late-maturity in fruits or fruit blast. Real-time quantitative RT-PCR analysis revealed that the relative proportion of the virus titers was distinct in the two sampled trees. The PNRSV titer was significantly higher than the four other viruses in the trees that exhibited fruit blast. Phylogenetic analysis of the PNRSV coat protein (CP) gene showed that the isolates HSY-4-1 and X-3, obtained from the two sampled trees separately, were classified into different subgroups of Group I isolates, which is characterized by a six-nucleotide insertion. A non-synonymous substitution was identified in the six-nucleotide insertion in the PNRSV CP gene in one of the two isolates. This is the first detailed study of the incidence of multiple sweet cherry viruses in China.

Early tree growth, productivity, fruit quality and leaf nutrients content of sweet cherry grown in a high density planting system

Milosevic T., Milosevic N., Glisic I., Nikolic R., Milivojevic J . (2014): Early tree growth, productivity, fruit quality and leaf nutrients content of sweet cherry grown in a high density planting system . Hort. Sci. (Prague), 42: 1–12. From 2008 to 2013 the phenology, early tree growth, precocity, yield, fruit quality attributes and leaf nutrient status of four sweet cherry cultivars (May Early, Germersdorfer, Sunburst and Celeste) were evaluated on Colt rootstock in the Cacak region (Serbia) with 1,250 trees/ha. The soil type was heavy and acidic. The results showed that cv. May Early blossomed and ripened earlier than the other cultivars, and had the highest tree vigour, better yield performance and the poorest fruit physico-chemical attributes. The best fruit quality was found in cv. Sunburst which is categorized as a low precocious cultivar with small yield capacity. Lower tree vigour, good productivity and fruit quality were shown by cv. Celeste. In general, leaf analysis indicated that all cultivars had excessive levels of N and Cu, and in some cases P, whereas K, Ca, Mg, Fe, Mn, Zn and B were deficient in all cultivars. The best balanced nutritional values (ΣDOP) were observed in cv. Sunburst, whereas wider imbalance was observed in cv. Celeste for macronutrients. In contrast, the ΣDOP for micronutrients indicated that cv. Celeste had the best balanced nutritional values, whereas cv. Sunburst had the worst.

FACTORS AFFECTING POSTHARVEST FUNGAL FRUIT DECAY IN SWEET CHERRY IN A COOL, WET CLIMATE

The growing season in Norway is characterized by a relatively cool and wet climate, and all commercial sweet cherry production takes place under plastic roofs or in plastic tunnels for protection against rain and thus reduction of fruit cracking and fungal fruit decay. Fungal pathogens found to cause postharvest decay in Norway include Monilinia sp., Botrytis cinerea, Mucor piriformis, Colletotrichum acutatum, Penicillium sp. and Cladosporium sp. The following experiment with postharvest fruit decay took place over two seasons: Samples of 5A—100 fruit of ‘Lapins’ and ‘Van’ from orchards delivering fruit to three packing houses, were stored for 10 days in Life Span® bags at 2°C followed by 2-3 days at 20°C. Averaged over all fruit assessed, 55% developed fungal decay after storage in the first season and 4% in the following season. However, the amount of decay differed greatly between packing houses and orchards. In the season with high incidence, fruit decay varied from 12 to 100% and 1.6 to 95% on ‘Van’ and ‘Lapins’, respectively. Respective data for the successive season were 0 to 38% on ‘Van’ and 0 to 41% on ‘Lapins’. Mucor rot was the dominant cause of fruit decay in both years. Factors affecting postharvest decay are discussed.

Exergetic performance of production unit operations of a frozen fruit: a case study for sweet cherry

In the present study, energetic and exergetic assessments were conducted in a frozen cherry production process. Actual operational data were used to indicate energy and exergy efficiencies and irreversibilities of each operation units. Production process was divided into four main operations of pre–washing, stemming, pitting and individually quick frozen (IQF). Energy and exergy efficiencies of the entire system were found as 65.74% and 8.95%, respectively. Exergy analysis revealed that IQF Freezing was responsible for the most of the exergy destruction (over 90%) followed by pitting process (3.38%). Use of an effective pre–cooling unit operation before freezing was suggested to improve the energetic and exergetic performances of the system.

EFFECT OF POLLINATION ON FRUIT SET AND EVALUATION OF PHENOLOGICAL, POMOLOGICAL AND MORPHOLOGICAL CHARACTERISTICS OF SOME INTRODUCED SWEET CHERRY CULTIVARS UNDER KHORASAN RAZAVI PROVINCE

Self and cross-incompatibility is one of the limiting factors in sweet cherry production. Scince some self-compatible exotic sweet cherry cultivars have been recently introduced to Iran, this study was conducted to investigate adabtibility of six introduced cultivars Summit, Red Dorfi clone 3, Sunburst, Samba, Blamarka and a local cultivar Siah Mashhad in Khorasan Razavi, Mashhad, Iran during 2010-2013. In most cultivars, flower buds were formed and developed on spurs, however flower formation in annual shoots was also observed. There were significant differences among cultivars for vegetative characters (height, width, crown volume and current season vegetative growth). Cultivars Summit and Sunburst had the highest and the lowest vegetative growth, respectively. There was 10 days variation in start of flowering time. Blamarka and Summit were early (27 March) and late (6 April) blooming cultivars, respectively. The results showed that fruit weight of cultivars was significantly different and Blamarka (3.14 g) and Sunburst (9.83 g) had the lowest and the highest fruit weight, respectively. Summit, Samba, Blamarka, and Siah-Mashhad were self-incompatible and cultivars Stella, Red Dorfi clone 3 clone and Sunburst were self-compatible under Khorasan Razavi province conditions.

First Report of Cherry mottle leaf virus Infecting Cherry in China

Cherry mottle leaf virus (CMLV) is a member of the genus Trichovirus (family Betaflexiviridae). CMLV infects several species of the genus Prunus including cherry (Prunus avium) and peach (P. persica) (2,3). It is spread via budding and grafting with infected wood and can be transmitted from infected bitter cherry (P. emarginata), or infected but symptomless peach trees to healthy sweet cherry trees by the bud mite (Eriophyes inaequalis) (1). On susceptible sweet cherry cultivars, CMLV causes symptoms such as chlorotic mottle-leaf pattern, distortion, puckering of younger leaves, and small fruits that ripen late (1), which may lead to severe economic losses in some cultivars. Cherry is one of the most important fruit tree species in North China, and Shandong Province is one of the major cherry production areas. In June 2013, a survey of possible CMLV presence was conducted in a cherry orchard planted in 1996 in Zoucheng city, Shandong. The sweet cherry cultivars in this orchard included Black Tartarian, Bing, Hongdeng (a hybrid between cvs. Napoleon and Huangyu), and others; the rootstock cultivar utilized to graft these cultivars was mountain cherry (P. tomentosa). During the survey, characteristic symptoms on leaves such as leaf mottling, distortion, and puckering similar to those caused by CMLV were observed on some trees of the cv. Hongdeng, and the symptomatic trees accounted for ~10% of the total trees of this cultivar. Five symptomatic cherry leaf samples and three healthy-looking cherry leaf samples of cv. Hongdeng were collected. Total RNA extracted from the leaf samples using RNeasy plant mini kit (Qiagen Inc., Valencia, CA) was subjected to first strand cDNA synthesis with the reverse primer CMLV-3R (5'-CTCGAGAACACAGAGATTTGTCGAGAC-3', sequence in italics indicates restriction site XhoI) and M-MLV reverse transcriptase (Promega, Madison, WI) according to the manufacturer's instruction. The cDNA was then used as template in the PCR assay using primers CMLV-5F (5'-GGATCCATGTCGGCGCGATTGAATC-3', sequence in italics indicates restriction site BamHI) and CMLV-3R, which amplify the genome fragment including the capsid protein gene of CMLV. The expected PCR product ~590 bp was amplified from all five symptomatic samples, while no such PCR product was amplified from the symptomless samples. The PCR products were cloned into pMD18-T vector (TaKaRa, Dalian, China). Three positive clones for each of the five amplicons were sequenced in both directions. Sequence alignment and nucleotide BLAST analysis of the sequences revealed that they were 99% to 100% identical to the corresponding capsid protein gene sequence of a cherry isolate of CMLV (GenBank Accession No. AF170028) and 85% identical with that of the peach wart strain of CMLV (KC207480). Our results confirm the infection of cherry trees by CMLV in Shandong. To our knowledge, this is the first report of CMLV on cherry in China. As the spread of CMLV by mite vector in the field is rare (1), and no bud mite outbreak had occurred in this orchard in the past years, so it is possible that virus-infected propagation materials are largely responsible for the spread of this virus. Considering the importance of cherry cultivation in China, this report prompts the need to survey the occurrence of this virus in Shandong and other provinces, and the need to develop more effective management strategies such as the use of certified virus-free nursery stocks to reduce the impact of CMLV.

First Report of Brown Rot Caused by Monilia mumecola on Chinese Sour Cherry in Chongqing Municipality, China.

Cherry is widely planted in China, from Liaoning, Beijing, Hebei, Shandong, Zhejiang, Jiangsu, and Anhui provinces (eastern China), to Shaanxi, Sichuan, Chongqing, and Guizhou provinces (western China). The brown rot fungus Monilinia fructigena causes considerable production losses in cherry production in Liaoning Province (3). In May 2013, Chinese sour cherry (Prunus pseudocerasus) cv. Wupi displaying symptoms of brown rot was found in an orchard in Chongqing municipality. Diseased cherry fruit had a brown rot sporulating with grayish, conidial tufts. The fruit later succumbed to the soft rot or shivered and became a mummy. Single-spore isolations on PDA resulted in colonies with concentric rings of pigmented mycelium with lobbed margins. Conidia were broadly ellipsoid to subglobose, occasionally even globose, with an average size of 16 × 12.7 μm. Multiple germ tubes were produced from each conidium, a germination pattern unique to Monilia mumecola (1,2,4). The pathogen identity was confirmed by multiplex PCR as described by Hu et al. (2). The PCR resulted in a 712-bp amplicon, which is diagnostic of M. mumecola. Further sequencing of the internal transcribed spacer (ITS) region 1 and 2 and 5.8S gene further indicated 100% identity with that of M. mumecola isolates from China (Accession No. HQ908786) and from Japan (AB125613, AB125614, and AB125620). Koch's postulates were confirmed by inoculating mature cherry fruit with mycelia plugs. Inoculated fruit were placed in a sterilized moist chamber, and incubated at 22°C with 12 h light/dark cycle. Inoculated fruit developed typical brown rot symptoms only 2 days after inoculation, while the control fruit, inoculated with a sterile PDA plug, remained healthy. The pathogen isolated from inoculated symptomatic fruit was confirmed to be M. mumecola based on morphological characteristics and germination pattern. It should be noted that the conidia on inoculated fruit showed an average size of 20 × 15.3 μm, significantly bigger than that of from PDA, and most produced more than three germ tubes. The inoculation experiments were performed in triplicates. M. mumecola was first reported as the causal agent of brown rot of mume in Japan in 2004 (1). Later studies demonstrated that it is also pathogen on other stone fruits, e.g., peach, nectarine (2), and apricot (4). To our knowledge, this is the first report of cherry brown fruit rot caused by M. mumecola, and the first report of M. mumecola in Chongqing municipality.

Scattered shade trees improve low-input smallholder Arabica coffee productivity in the Northern Lake Kivu region of Rwanda

In suboptimal conditions for coffee growth, the use of shade tree is usually considered beneficial to production. This study aimed to evaluate this benefit in the poorly documented East African smallholder Arabica coffee systems in optimal climatic but suboptimal management conditions. In a 4 year observational trial in 50 coffee farms, the association of shade trees and coffee generated an average 55 % cherry production increase. Neither delay in berry maturation nor buffer in alternate bearing patterns were observed, probably due to the low productivity of unfertilized coffee plants. Quality wise, the presence of shade trees did not result in an increase of larger green beans, but it reduced the proportion of altered and lighter cherries in 2009, a low production year. A shade species effect was detected through the positive influence of two non-leguminous shade trees, Persea americana and Ficus thonningii on production. The effect was correlated to greater canopy openness and increase in K soil content. In general, soil mineral content was not influenced by the presence of trees, but the legume species Inga oerstediana appeared responsible for a slight increase of total C and N soil content. It is concluded that in the small holder context of the Northern Lake Kivu region, the association of mature trees is beneficial to coffee production and can contribute to the improvement of producer’s income.

Variation in cold hardiness of sweet cherry flower buds through different phenological stages

Freezes during early spring can damage flower buds of sweet cherry (Prunus avium L.). The reduction in sweet cherry production due to cold injury to floral tissue can be significant and is a common and serious problem for growers and commercial producers in the Pacific Northwest and other regions of the US. The critical temperatures affecting the bud and the associated damage are variable and unknown for most of the new cherry cultivars. The goal of this study was to identify the critical temperatures of cherries buds at different development stages, using differential thermal analysis (DTA) and a traditional cold exposure method for assessing cold damage. Three sweet cherry cultivars including Bing, Chelan and Sweetheart were tested during the late winter to early spring seasons of 2012 and late fall to early spring season of 2013. The DTA showed that the temperature causing freezing injury was related to the initiation of the low temperature exotherms (LTE's), the value of the lethal temperature changes depending on the cultivar and bud development stage. High (HTE) and low temperature (LTE) exotherms were clearly identified for the different cherry cultivars that were evaluated during the early stages of bud development. Cold hardiness increased from late fall through mid-January, followed by deacclimation for the remainder of the winter months. During deacclimation, DTA was not an effective method for detecting LTE in cherry buds. Therefore, a traditional approach that exposes the tissue to different cold regimens was used for the remaining period of bud and flower development. To determine the total number of buds and flowers that were killed due to cold exposure, a simple evaluation using dissections under a stereoscope was conducted. Logistic models were developed for the freeze-survival data for both methods. Differences in hardiness were found for all the cherry cultivars that were evaluated as well as between different sampling dates. The information that was generated in this study will provide a better understanding of cherry cold hardiness and will support growers in decision-making of frost control practices.

First Report of Infection of Cherry Rusty Mottle Associated Virus in Portuguese Laurel (Prunus lusitanica) in Washington State.

During late spring of 2012 in Snohomish County of Washington State, chlorotic yellow leaf blotch symptoms suggestive of a virus infection were observed on Portuguese laurel (Prunus lusitanica) planted in a hedge row. Leaf samples from representative trees were initially tested for the presence of Cherry leaf roll virus (CLRV) and Plum pox virus (PPV) by ELISA with antibodies specific to CLRV and general potyvirus, respectively (Agdia, Inc., Elkhart, IN). The ELISA test yielded negative results for both viruses. Reverse transcription (RT)-PCR was pursued to detect other viruses known to infect Prunus spp., namely American plum line pattern virus (APLPV), Apple chlorotic leafspot virus (ACLSV), Cherry mottle leaf virus (CMLV), Cherry raspleaf virus (CRLV), Cherry virus A (CVA), Prune dwarf virus (PDV), and Prunus necrotic ringspot virus (PNRSV), as well as CLRV and PPV. None of these viruses were detected. However, RT-PCR with a generic primer pair Fovea2/AdPr (3) that amplifies the coat protein (CP) coding sequence and 3'-untranslated regions (3'-UTR) of several members of the family Betaflexiviridae yielded a 1.4-kb amplicon that was cloned into pCR2.1 (Invitrogen, Carlsbad, CA) and sequenced (GenBank Accession No. KF356396). The sequences from three clones were 99.8% identical to each other at the nucleotide level. Comparison of the consensus CP coding region with the nucleotide sequence database revealed 86 to 93% identity to Cherry rusty mottle associated virus (CRMaV), and only 73 to 75% identities to Cherry necrotic rusty mottle virus (CNRMV) (1) and 71 to 76% identities to Cherry green ring mottle virus (CGRMV) (4) isolates from sweet cherry (P. avium). This result suggested that the cloned fragment represents a strain of CRMaV. Prunus avium 'Bing' and 'Sam,' and P. serrulata 'Kwanzan' were grafted with bark patches from the symptomatic tree and observed for induction of cherry rusty mottle disease (CRMD) symptoms. Ninety days after grafting, symptoms typical of CRMD consisting of chlorotic yellow mottle appeared on 'Bing,' 'Sam,' and 'Kwanzan' indicators. Small necrotic spots also appeared on the leaves of the latter. Angular necrotic lesions on 'Sam' and epinasty of 'Kwanzan' that are diagnostic symptoms of cherry necrotic rusty mottle disease (CNRMD) and cherry green ring mottle disease (CGRMD), respectively, were absent from graft inoculated indicators. Further RT-PCR tests on the indicators using primers specific to CNRMV, CGRMV, and CRMaV (2) yielded negative results for CNRMV and CGRMV but showed positive amplification for CRMaV. The results of the woody indexing corroborate the presence of CRMaV but the absence of CNRMV and CGRMV in the symptomatic Portuguese laurel. To our knowledge, this is the first report of CRMaV in Portuguese laurel in the United States and the first description of symptoms associated with CRMaV in this host. As a potential reservoir of CRMaV, Portuguese laurel could play an important component in management of CRMD in cherry production areas where this ornamental cherry is also present.

Temperature-Related Development and Population Parameters forDrosophila suzukii(Diptera: Drosophilidae) on Cherry and Blueberry

Temperature-related studies were conducted on Drosophila suzukii Matsumura (Diptera: Drosophilidae: Drosophilini). From 10-28°C, temperature had a significant impact on blueberries, Vaccinium corymbosum L. (Ericales: Ericaceae), and cherries, Prunus avium (L.) L. 1755 (Rosales: Rosaceae), important commercial hosts of D. suzukii. Temperature had a significant influence on D. suzukii developmental period, survival, and fecundity, with decreasing developmental periods as temperatures increased to 28°C. At 30°C, the highest temperature tested, development periods increased, indicating that above this temperature the developmental extremes for the species were approached. D. suzukii reared on blueberries had lower fecundity than reared on cherries at all temperatures where reproduction occurred. The highest net reproductive rate (R(o)) and intrinsic rate of population increase (r(m)) were recorded on cherries at 22°C and was 195.1 and 0.22, respectively. Estimations using linear and nonlinear fit for the minimum, optimal, and maximum temperatures where development can take place were respectively, 7.2, 28.1, and 42.1°C. The r(m) values were minimal, optimal, and maximal at 13.4, 21.0, and 29.3°C, respectively. Our laboratory cultures of D. suzukii displayed high rates of infection for Wolbachia spp. (Rickettsiales: Rickettsiaceae), and this infection may have impacted fecundity found in this study. A temperature-dependent matrix population estimation model using fecundity and survival data were run to determine whether these data could predict D. suzukii pressure based on environmental conditions. The model was applied to compare the 2011 and 2012 crop seasons in an important cherry production region. Population estimates using the model explained different risk levels during the key cherry harvest period between these seasons.

Comparative analisis of different canopy forms of sweet cherry cultivars

The Hungarian sweet cherry production has been changed significantly in the last decades, which primarily resulted in growing intensity of the orchards. Due to the favourable selling prices of the sweet cherry many growers see good prospects in this fruit. One of the key questions of their success is the choice of the most proper canopy form according to the growing conditions, which facilities the efficient completion of annual technological operations.&#x0D; In new orchards almost exclusively variations of spindle canopies are established, although many other crown forms are used all over the world. From the point of the domestic sweet cherry production it is indispensable to get information about these canopies, and compare with the prevailing crown forms with central axis.&#x0D; In our experiment we compared free spindle and bush canopies in the Horticultural Experimental Farm of the University of Debrecen in 2013. According to our results it can be stated that the bush canopy can be described with more balanced growth, which makes easier to maintain the vegetative and generative balance. Another positive characteristic of the bush canopy is, that the height of the trees is smaller with 50% compared with the free spindle, which makes the pruning and the harvest easier.

First Report of Sweet Cherry Virescence Disease in China and Its Association with Infection by a 'Candidatus Phytoplasma ziziphi'-Related Strain.

Sweet cherry (Prunus avium L.) is a deciduous tree originating in the Black Sea/Caspian Sea region where Asia and Europe converge. Being highly valued for its timber and fruit, sweet cherry has been cultivated and naturalized on all continents. Over the past decade, the area of sweet cherry cultivation increased rapidly in China and has reached 140,000 ha. In April 2013, sweet cherry trees (cv. Summit) exhibiting floral virescence symptoms were observed in two orchards located in suburban Taian, Shandong Province, China. The diseased trees developed flowers having white petals with green veins or abnormal floral structures having cupped, green petals. The affected flowers failed to set fruit. A month following the first appearance of the virescence symptoms, the diseased trees became wilted and eventually died. Leaf and stem samples were collected from nine symptomatic and two nearby symptomless trees. Total DNA was extracted from each sample using the Plant Quick DNA Extract Kit (TianGen, Beijing, China). Nested-PCR was carried out using phytoplasma-universal primer pairs P1/P7 and R16F2n/R16R2 (1). All PCR assays with DNA templates from symptomatic samples yielded an amplicon of 1.25 kb, corresponding to the full-length F2nR2 region of phytoplasmal 16S rDNA. No amplicon was generated in PCRs containing DNA templates from symptomless plants. The amplicons were cloned into plasmid vector pMD18-T (TaKaRa, Dalian, China) and sequenced. The obtained sequences were nearly identical, and a representative sequence was deposited into GenBank (Accession No. KF268424). An analysis of the sequence through the iPhyClassifier (4) revealed that the sweet cherry virescence (SCV) disease was associated with infection by a phytoplasma closely related to the reference strain of 'Candidatus Phytoplasma ziziphi.' The 16S rDNA F2nR2 region of the SCV phytoplasma shared 99.8% nucleotide sequence identity with that of 'Candidatus Phytoplasma ziziphi' reference strain (Accession No. AB052876). A computer-simulated restriction fragment length polymorphism (RFLP) analysis of the SCV phytoplasma 16S rDNA F2nR2 sequence with a set 17 restriction enzymes (3) resulted in a collective RFLP profile identical to the reference pattern of the elm yellows phytoplasma group, subgroup B (16SrV-B). Phytoplasmal diseases of sweet cherry were reported previously in Europe and the etiological agents were phytoplasmas of other groups, including the aster yellows group (16SrI), the X-disease group (16SrIII), and the apple proliferation group (16SrX) (2). To our knowledge, this is the first report of a phytoplasmal disease of sweet cherry in China, and the SCV phytoplasma is a new member of the subgroup 16SrV-B. Presence of 16SrV-B phytoplasmas and their etiological association with various plant diseases in China have been reported previously; affected host plants included jujube, hemp fiber, paper mulberry, Chinese cherry, plum, apricot, red barberry, clover, dianthus, elm, and sunshine tree. Our identification of the SCV phytoplasma expands the known plant host range of the 16SrV-B phytoplasma lineage. The impact of the SCV phytoplasma in the regional ecosystem and in sweet cherry production is being assessed.

Climate, Winter Chill, and Decision-making in Sweet Cherry Production

Growers naturally adapt and manage production for unpredictable and variable seasonal climates; however, the projected changes in climate introduce a new concern with increased variability in the frequency and severity of extreme climatic events and sustained changes in temperature. This study addresses the complexity of providing clear winter chill information in a form that facilitates grower assimilation and application of that information, ultimately to assist decision-making around variety selection and management. This study established the chill requirement for two commonly grown sweet cherry (Prunus avium L.) varieties: ‘Kordia’ and ‘Sweetheart’, and explored the uniformity of bud burst in each. It was found that varieties required different chill hours and that ‘Sweetheart’ reached mean time to, and maximum total bud burst, faster than ‘Kordia’, but no subsequent impact on uniformity of maturity at harvest. There was no significant difference in uniformity of burst between the two varieties. The results obtained by matching chill accumulation to tree phenology showed that cherry-producing regions in Australia will experience sufficient chill to support the production of the variety ‘Sweetheart’ with an increase in mean winter temperature of 1 °C. Regions in Western Australia and Queensland will become marginal, or not suitable, for ‘Kordia’.