Sweet Cherry Cv Research Articles

Evaluation of cherry cultivar susceptibility to bacterial canker and leaf spot disease

AbstractIn this study, the susceptibility of different sweet (19) and sour cherry (3) cultivars (cvs.) to the bacterial pathogens Pseudomonas syringae pv. syringae and P. s. pv. morsprunorum race 1 causing bacterial canker (sensu stricto) and leaf spot was evaluated. Susceptibility to bacterial canker was examined by artificial inoculations of 1‐year‐old rooted trees, which revealed susceptibility of all cvs. to both P. syringae pathovars. Susceptibility level differed among cvs.; sweet cherry cvs. Katalin, Linda, Summit, New Star and Bigarreau Burlat were highly susceptible, sour cherry cvs. Érdi bôtermô and sweet cherry Drogan's Yellow, Carmen, Germersdorfer and Noir de Meched were susceptible. Sour cherry cvs. Španska and Újfehértói fürtös, as well as sweet cherry cv. Rita were found to be less susceptible to bacterial canker. Susceptibility to bacterial leaf spot disease was evaluated on naturally infected (field conditions) and artificially inoculated leaves (laboratory conditions). Severe symptoms of bacterial spot with shot hole appearance were observed in cherry leaves at the beginning of May under field conditions. In all collected leaf samples, presence of P. s. pv. morsprunorum race 1 was determined. Sweet cherries Valery Chkalov, Summit, Bigarreau Burlat and New Star were highly susceptible to this bacterium. No symptoms of bacterial spot were found on sweet cherries Solomary gomboly, Linda, Germersdorfer, Hedelfinger, Katalin, Margit, Carmen, Aida, Sunburst, Alex, Peter, Rita and Kavics and sour cherry Érdi bôtermô. In laboratory conditions, susceptibility of the tested cvs. varied and mostly depended on the inoculation method. Nonetheless, sweet cherry cvs. Carmen and Margit and sour cherry Érdi bôtermô exhibited a certain level of resistance.

Effects of Modified Atmosphere Packaging and 1 - Methylcyclopropene during Storage and Shelf Life of Sweet Cherry Cv. 0900 Ziraat

Effects of Modified Atmosphere Packaging and 1 - Methylcyclopropene during Storage and Shelf Life of Sweet Cherry Cv. 0900 Ziraat

Cloning and expression profiling of the PacSnRK2 and PacPP2C gene families during fruit development, ABA treatment, and dehydration stress in sweet cherry

Plant SNF1-related protein kinase 2 (SnRK2) and protein phosphatase 2C (PP2C) family members are core components of the ABA signal transduction pathway. SnRK2 and PP2C proteins have been suggested to play crucial roles in fruit ripening and improving plant tolerance to drought stress, but supporting genetic information has been lacking in sweet cherry (Prunus avium L.). Here, we cloned six full-length SnRK2 genes and three full-length PP2C genes from sweet cherry cv. Hong Deng. Quantitative PCR analysis revealed that PacSnRK2.2, PacSnRK2.3, PacSnRK2.6, and PacPP2C1–3 were negatively regulated in fruits in response to exogenous ABA treatment, PacSnRK2.4 and PacSnRK2.5 were upregulated, and PacSnRK2.1 expression was not affected. The ABA treatment also significantly promoted the accumulation of anthocyanins in sweet cherry fruit. The expression of all PacSnRK2 and PacPP2C genes was induced by dehydration stress, which also promoted the accumulation of drought stress signaling molecules in the sweet cherry fruits, including ABA, soluble sugars, and anthocyanin. Furthermore, a yeast two-hybrid analysis demonstrated that PacPP2C1 interacts with all six PacSnRK2s, while PacPP2C3 does not interact with PacSnRK2.5. PacPP2C2 does not interact with PacSnRK2.1 or PacSnRK2.4. These results indicate that PacSnRK2s and PacPP2Cs may play a variety of roles in the sweet cherry ABA signaling pathway and the fruit response to drought stress.

Are commercial sweet cherry rootstocks adapted to climate change? Short-term waterlogging and CO2 effects on sweet cherry cv. 'Burlat'.

High CO2 is able to ameliorate some negative effects due to climate change and intensify others. This study involves the sweet cherry (Prunus avium) cultivar 'Burlat' grafted on the 'Mariana 2624', 'Adara' and 'LC 52' rootstocks. In a climate chamber at two CO2 concentrations, ambient (400 µmol mol-1 ) and elevated (800 µmol mol-1 ), the plants were submitted to waterlogging for 7 d, followed by 7 d of recovery after drainage. Waterlogging drastically decreased the rate of photosynthesis, significantly endangering plant survival, particularly for the 'LC 52' and 'Adara' rootstocks. 'Mariana 2624' was also clearly affected by waterlogging that increased lipid peroxidation and the Cl- and SO42- concentrations in all the studied plants. Nevertheless, CO2 was able to overcome this reduction in photosynthesis, augmenting growth, increasing soluble sugars and starch, raising turgor and regulating the concentrations of Cl- and SO42- , while lowering the NO3- concentration in leaves of all the studied rootstocks. In concordance with these results, the proline levels indicated a more intense stress at control CO2 than at high CO2 for waterlogged plants. 'Mariana 2624' was more resistant to waterlogging than 'Adara', and both were more resistant than 'LC 52' in control CO2 conditions; this clearly enhanced the chance of survival under hypoxia.

PacMYBA, a sweet cherry R2R3-MYB transcription factor, is a positive regulator of salt stress tolerance and pathogen resistance

Plant R2R3-MYB transcription factors play crucial roles in stress responses. We previously isolated a R2R3-MYB homolog from sweet cherry cv. Hong Deng, designated PacMYBA (GenBank accession No. KF974774). To explore the role of PacMYBA in the plant stress response, we heterologously expressed PacMYBA in transgenic Arabidopsis thaliana plants. In a previous study, we demonstrated that PacMYBA is mainly localized to the nucleus and could be induced by abscisic acid (ABA). Analysis of the promoter sequence of PacMYBA revealed that it contains several stress-related cis-elements. QPCR results showed that PacMYBA is induced by salt, salicylic (SA), and jasmonic acid (JA) in sweet cherry leaves. Transgenic Arabidopsis plants heterologously expressing PacMYBA exhibited enhanced salt-tolerance and increased resistance to Pseudomonas syringe pv. tomato (Pst) DC3000 infection. Overexpression of PacMYBA decreased the osmotic potential (OP), increased the free proline content, and increased the peroxidase content in transgenic Arabidopsis plants. Furthermore, overexpression of PacMYBA also affected the expression levels of salt stress- and pathogen defense-related genes in the transgenic plants. These results indicate that PacMYBA is a positive regulator of salt stress tolerance and pathogen resistance.

Response of different soil moisture regimes on sweet cherry under Karewa land of Kashmir valley

The field experiment was conducted to ascertain the soil moisture regime under drip irrigation for Karewa land in sweet cherry cv. Bigarreau Noir Grossa with reference to qualitative and quantitative attributes. Results indicated that maximum yield of 73.26 kg/tree was recorded with 80% ET as compared to 100% ET which registered only 64.73 kg/tree yield. The minimum yield of 50.50 kg/tree was noted when irrigation level was maintained at 40% ET. Further, the maximum fruit weight (4.51 g) was achieved with 100% ET followed by 80% ET and it decreased gradually to a minimum of 3.08 g with 40% ET. As far as qualitative characters are concerned, the maximum TSS of 23.02oBrix was observed when the irrigation level was maintained at 80% ET. This treatment also gave the highest TSS: acid ratio indicating an improvement in fruit quality. Fruit cracking was significantly reduced by maintaining the irrigation regime in between 80% (2.72%) to 100% (1.96%) ET as compared to irrigation level maintained at 60% (10.91%) and 40% ET (16.25%), indicating 80% reduction in fruit cracking. Sweet cherry plant with irrigation level maintained at 80% ET showed better nutrient uptake. The leaf Fe, Mn, Cu and Zn contents were maximum with 80% ET followed by 100% ET and minimum was recorded with 40% ET.

Protoplast isolation and development of a transient expression system for sweet cherry (Prunus avium L.)

Transient gene expression in plant protoplasts is a powerful tool for analyzing gene function and for performing biotechnical manipulations. Here we report the isolation of viable protoplasts from the fruit flesh of sweet cherry (Prunus avium L.) cv. Hong Deng and their polyethylene glycol (PEG)-mediated transient transfection using green fluorescent protein (GFP) as a marker gene. We investigated the main factors affecting the efficacy of protoplast isolation and transfection, including the composition of the enzymolysis solution, enzymolysis time, pH of the enzymolysis solution, PEG concentration, and transfection time. Protoplast isolation was optimal when the tissue was incubated in enzymolysis solution composed of 1.0% Cellulase R-10, 0.5% Pectolase Y-23, and 0.6M mannitol (pH 5.8) for 18h, resulting in a protoplast yield of 4.3×106protoplasts/g fresh weight [FW] and viability of 84.1%. Protoplast transformation efficiency was measured by transient expression of the GFP reporter gene, and transformation efficiency was highest when protoplasts were incubated in transfection medium containing 40% PEG for 15min. Collectively, this work describes an efficient protoplast isolation and protoplast transient expression system that can be used to facilitate molecular biology research in sweet cherry.

Rootstock effects on the growth, yield and fruit quality of sweet cherry cv. ‘Newstar’ in the growing conditions of the Region of Murcia

The influence of Adara, Gisela 5, Gisela 6, Mariana 2624, MaxMa 14, Mayor, Pikú 1, Pikú 3, Pikú 4 and Saint Lucie GF 64 rootstocks onto vigour, yield and fruit quality of ‘Newstar’ cultivar was studied during four years. The experiment was performed in Jumilla (Murcia, Spain), on a heavy and calcareous soil. Significant differences in parameters such as vigour, yield, fruit weight and size, soluble solids content, titratable acidity, skin colour and firmness were found among some rootstocks. Most of them achieved optimal coloration values that would have a high commercial acceptance. Gisela 6, Pikú 1, SL 64 and Mayor rootstocks showed high mortality by root asphyxia strongly related to drainage problems in heavy soils. Fruits from trees grafted on MaxMa 14 had the smallest size and the most intense coloration. The excessive vigour reduction in Gisela 5, together with a low yield and fruit quality, resulted in a non-interesting rootstock for our growing conditions. By contrast, Mariana 2624, Mayor and Adara were the most vigorous rootstocks and presented the highest yields with good fruit quality and the best agronomic performance, being their use advisable in warm Mediterranean regions such as the Region of Murcia. Although Pikú 3 induced low yield and obtained the highest values in fruit size, soluble solids content and fruit firmness, which, along with its low mortality, seem to recommend its introduction and use for producing high quality sweet cherries. The work demonstrates that rootstocks have been decisive in the vigour and yield of the grafted cultivar, as well as the size, acidity, colour and firmness of the fruit.

Ten years field trial observations of ri-TDNA cherry Colt rootstocks and their effect on grafted sweet cherry cv Lapins

Ten year field trials of ri 1855 T-DNA cherry Colt plants have been examined for their vegetative and reproductive behaviours and for their effect on grafted “Lapins”. These plants have been regenerated in vitro from roots produced after the infection with Agrobacterium rhizogenes wild type. The clones, from different transfection events (A, B and E) showed different morphologies since their first months in pots. This allowed an initial selection for the suitable dwarf rootstocks to fit farmers’ needs. The clones with the most reduced size, clones A and E, showed the typical “hairy root” phenotype more distinctly than clone B. in vitro All the clones’ explant rooting resulted very high even in auxin-free medium, while in vivo, both semi-hardwood cuttings and layering suckers, resulted very low. Neither exogenous treatments with cytokinins, in an attempt to re-establish the hormonal unbalance caused by the bacterial genes, nor putrescine, H2O2 and girdling were effective in promoting satisfactory rooting. The ri-TDNA Colt clones, when used as rootstocks, reduced the bi-member plant size by different extents, according to their vigour and did not affect fruit quality. Clones A and E drastically reduced the plant size with a slight reduction of flower density and an extension of vegetative growth in Autumn. Clone B on the other hand, resulted in a promising dwarfing rootstock for sweet cherry since it did not induce any evident negative effect on scion. This work encourages the selection of suitable dwarfing rootstocks among plants originated from several different modified roots, in other species as well. In particular, the work addresses the issue of whether these plants should or should not be subject to the same GMO law.

A Role for PacMYBA in ABA-Regulated Anthocyanin Biosynthesis in Red-Colored Sweet Cherry cv. Hong Deng (Prunus avium L.)

The MYB transcription factors and plant hormone ABA have been suggested to play a role in fruit anthocyanin biosynthesis, but supporting genetic evidence has been lacking in sweet cherry. The present study describes the first functional characterization of an R2R3-MYB transcription factor, PacMYBA, from red-colored sweet cherry cv. Hong Deng (Prunus avium L.). Transient promoter assays demonstrated that PacMYBA physically interacted with several anthocyanin-related basic helix-loop-helix (bHLH) transcription factors to activate the promoters of PacDFR, PacANS and PacUFGT, which are thought to be involved in anthocyanin biosynthesis. Furthermore, the immature seeds of transgenic Arabidopsis plants overexpressing PacMYBA exhibited ectopic pigmentation. Silencing of PacMYBA, using a Tobacco rattle virus (TRV)-induced gene silencing technique, resulted in sweet cherry fruit that lacked red pigment. ABA treatment significantly induced anthocyanin accumulation, while treatment with the ABA biosynthesis inhibitor nordihydroguaiaretic acid (NDGA) blocked anthocyanin production. PacMYBA expression peaked after 2 h of pre-incubation in ABA and was 15.2-fold higher than that of sweet cherries treated with NDGA. The colorless phenotype was also observed in the fruits silenced in PacNCED1, which encodes a key enzyme in the ABA biosynthesis pathway. The endogenous ABA content as well as the transcript levels of six structural genes and PacMYBA in PacNCED1-RNAi (RNA interference) fruit were significantly lower than in the TRV vector control fruit. These results suggest that PacMYBA plays an important role in ABA-regulated anthocyanin biosynthesis and ABA is a signal molecule that promotes red-colored sweet cherry fruit accumulating anthocyanin.

The effect of different types of rootstock on the quality of maiden trees of sweet cherry (Prunus avium L.) cv. ‘Regina’

Over the period 2006–2009 in Lublin, a study was conducted to determine the effect of five types of rootstock: ‘Colt’, ‘F12/1’, sweet cherry (<em>Prunus avium </em>L.), ‘GiSelA 5’ and ‘Piast’ mahaleb cherry (<em>Prunus mahaleb </em>L.), on the growth and quality of maiden sweet cherry trees cv. ‘Regina’ in a commercial nursery. Based on the three-year average, rootstocks were shown to have a significant effect on the investigated quality characteristics of maiden sweet cherry trees. Trees budded on ‘Colt’ vegetative rootstock were characterized by strongest growth and best quality. In each year, they were thicker, higher and better branched than sweet cherries on the rootstock. Under the tested conditions, ‘GiSelA 5’ dwarf rootstock significantly reduced the growth and quality of budded sweet cherry trees in the nursery. During the period 2007–2009, no physiological incompatibility symptoms were observed ‘Regina’ sweet cherry cv. and ‘Piast’ seedling rootstocks. The growth of trees budded on ‘Piast’ mahaleb cherry was poorer than on ‘Colt’ clonal rootstock, but it was stronger than on ‘F12/1’ and <em>Prunus avium</em> L. rootstocks.

Rootstock effect on the performance of sweet cherry cv. Lapins

Twelve clonal rootstocks of sweet cherry grafted with the cv. Lapins were tested. Each graft combination included 18 trees divided into six randomized blocks. The trees were spaced at 5 × 3 m and trained as spindles. Tree vigour, yield, fruit size, fruit quality and yield efficiency were evaluated for eleven subsequent years. According to trunk diameter, the most vigorous rootstocks were Gi 497/8, Gi 154/7, Gisela 4 and P-HL-A; 32-41% larger compared with the standard Gisela 5. The highest cumulative yield per tree and yield efficiency were recorded on the rootstocks Gi 154/7 and Gisela 4. The lowest yield was recorded on Damil, Gi 209/1, Gi 195/20, Gi 148/8 and Gisela 5. P-HL-A and Gi 523/02 gave the largest fruit weights and Gi 209/1, Gisela 5 and Gi 195/20 the smallest. Moderate tree die-back was recorded on Gi 154/7 and P-HL-A, low tree mortality on Gisela 4 and Damil. All the trees survived on Gi 497/8. Gisela 4 and Gi 154/7 produced some root suckers.

First Reports of Brown Fruit Rot on Sweet Cherry (Prunus avium) and Plum (P. domestica) and Shoot Blight on Apricot (P. armeniaca), Kwanzan Cherry (P. serrulata), and Sweet Cherry (P. avium) Caused by Monilinia laxa in New York, Rhode Island, and Massachusetts.

In the eastern United States, Monilinia laxa (Aderh. & Ruhl.) Honey has only been reported on tart cherry in New York (NY) (1). As a result of considerable rain in May of 2009 and 2011, an ornamental planting of Kwanzan cherries in Middletown, Rhode Island (RI), a planting of sweet cherry cvs. Ulster, Hedelfingen, Sam, and Lapins in Lanesboro, Massachusetts (MA), and plantings of apricot cvs. Harcot and Hargrande in Albion, Aurora, and Geneva, NY, and Harogem in Lanesboro, MA developed severe shoot blight (>15 to 100% of first-year shoots). Blighted shoots were wilted with the blight encompassing the distal end and often extending into second-year tissue with a distinct sunken margin. Leaves on symptomatic shoots had flushed, but were blighted and light brown. Blossom spurs were often blighted and gummosis was frequently observed at the base. In these same years, sweet cherry cv. Black Gold in Walworth, NY and plum cv. Stanley in Olcott, NY developed severe fruit rot (35 to 70% incidence). Plantings suffering from fruit rot had fruit lesions that began as pale brown, soft lesions with indiscriminant margins that covered 15 to 85% of the fruit surface area. Many blighted spurs, shoot tissues, and infected fruit were sporulating with tan-to-buff colored conidia produced in chains. From each planting with shoot blight, shoot tips were removed for pathogen isolation. Sections of symptomatic shoots (5 cm long) were surface sterilized in 0.6% NaOCl for 1 min and rinsed in sterile dH20. From plantings displaying blighted spurs or fruit rot, isolation was attempted directly from sporulating tissue. Cross sections of sterilized shoot tissue (3 mm thick) or tufts of sporulation from fruit and spurs were placed on potato dextrose agar amended with 50 μg/ml of streptomycin sulfate. After incubation at 24°C for 5 days, colonies with lobed margins, commonly described for M. laxa (4), were obtained. Several colonies resembling M. fructicola were isolated from all locations, but the majority of isolates from spurs and shoots resembled M. laxa. Conidia from both colony morphotypes were lemon shaped, but as expected, those from putative M. laxa isolates were smaller (10.75 × 12.0 μm) compared with those from putative M. fructicola isolates (15.75 × 18.25 μm) (4). Confirmation of M. laxa was further achieved by PCR amplification of the β-tubulin gene using M. laxa-specific primers as previously described (3). Pathogenicity of M. laxa isolates was proven by inoculating fruit of the stone fruit crop from which they were isolated as previously described (2). Fruit inoculated with M. laxa developed brown, soft sporulating lesions identical to the original observations, while those inoculated with water remained healthy. M. laxa was reisolated from symptomatic shoots and spurs, but not from water-inoculated tissues. The presence of M. laxa has been reported on tart cherries in NY (1), but to our knowledge, this is the first instance of economically devastating shoot blight on apricot in NY and MA, ornamental cherry in RI, and sweet cherry in MA and fruit rot on sweet cherry and plum in NY caused by M. laxa. In wet seasons, stone fruit growers may need to revise their chemical management programs to better prepare for M. laxa epidemics on several stone fruit species.

Effect of modified atmosphere packaging on chemical composition, antioxidant activity, anthocyanin, and total phenolic content of cherry fruits

The trend of postharvest changes in sweet cherry (Prunus avium) cv. Siah-e Mashhad, sour cherry (Prunus cerasus) cv. Erdi Bőtermő and Iranian local cultivar named Albaloo Mohallai were investigated. The traits were recorded included antioxidant activity, total anthocyanin and phenolic content, flesh firmness, titratable acidity (TA), soluble solids concentration (SSC), Juice pH, SSC/TA ratio and percentage of weight loss. They were evaluated at harvest after 15, 30, 45 and 60 days of storage in packages with modified atmosphere (MAP) and regular atmosphere (RAP) (control) and refrigerated at 0 ± 1°C. The results showed that the fruits packed in modified atmosphere had better quality than the ones packed in air due to higher SSC, TA, firmness, and lower pH, SSC/TA ratio and weight loss. All quality attributes diminished with storage time, while fruit firmness did not exhibit any particular trend during storage. The trends of total anthocyanin, phenolic content, and antioxidant activity during storage varied, depending on the cherry type. The negative correlation between antioxidant activity and fruit deformation (r from −0.49 to −0.72) was found.

Pre-harvest foliar application of Prohexadione-Ca and gibberellins modify canopy source-sink relations and improve quality and shelf-life of ‘Bing’ sweet cherry

This research evaluated the potential of gibberellins (GA), and Prohexadione-Ca (PCa) to affect sweet cherry (Prunus avium) fruit size and quality. The results demonstrate the ability of ostensibly counter-acting plant growth regulators to significantly improve sweet cherry cv ‘Bing’ fruit size, fruit quality and postharvest characteristics compared to the current commercial application of GA3 alone. In 2008, we found that the combination of GA3 or GA4/7 (30 mg l−1) with PCa (150 mg l−1) applied to entire 3-year-old limbs 30 days after anthesis increased fruit size and improved fruit quality in ‘Bing’. In 2009, we investigated the effect of application timing in larger-scale field trials, comparing treatments made at 30 or 37 days after anthesis, on fruit quality, storability and sensory attributes after storage. Treatment with PCa + GA3 or PCa + GA4/7 delayed fruit maturity by about 7 days compared to the untreated control. Both the first and second applications of PCa + GA4/7 resulted in 35–40% fruit being ≥10 g, compared with only 20% in the control. PCa + GA3 treatment also showed greater potential for improving fruit storability by maintaining fruit firmness, sweetness, and consumer appeal than PCa + GA4/7. PCa alone or in combination with GAs inhibited current shoot growth and delayed fruit coloring development. After 30 days of 4°C storage, fewer than 5% fruit from untreated trees were rated as healthy and marketable, compared to 50 and 30% fruit from PCa + GA3 treatment applied at 30 or 37 days after anthesis, respectively. In conclusion, preharvest foliar application of PCa + GA3 at the onset of Stage II of fruit development shows potential to affect canopy source-sink relations and improved quality and shelf life of ‘Bing’ sweet cherries.

Detection and Identification of ‘Candidatus Phytoplasma prunorum’, ‘Candidatus Phytoplasma mali’ and ‘Candidatus Phytoplasma pyri’ in Stone Fruit Trees in Poland

A survey was made to determine the incidence of phytoplasmas in 39 sweet and sour cherry, peach, nectarine, apricot and plum commercial and experimental orchards in seven growing regions of Poland. Nested polymerase chain reaction (PCR) using the phytoplasma-universal primer pairs P1/P7 followed by R16F2n/ R16R2 showed the presence of phytoplasmas in 29 of 435 tested stone fruit trees. The random fragment length polymorphism (RFLP) patterns obtained after digestion of the nested PCR products separately with RsaI, AluI and SspI endonucleases indicated that selected Prunus spp. trees were infected by phytoplasmas belonging to three different subgroups of the apple proliferation group (16SrX-A, -B, -C). Nucleotide sequence analysis of 16S rDNA fragment amplified with primers R16F2n/R16R2 confirmed the PCR/Restriction Fragment Length Polymorphism (RFLP) results and revealed that phytoplasma infecting sweet cherry cv. Regina (Reg), sour cherry cv. Sokowka (Sok), apricots cv. Early Orange (EO) and AI/5, Japanese plum cv. Ozark Premier (OzPr) and peach cv. Redhaven (RedH) was closely related to isolate European stone fruit yellows-G1 of the 'Candidatus Phytoplasma prunorum' (16SrX-B). Sequence and phylogenetic analyses resulted in the highest similarity of the 16S rDNA fragment of phytoplasma from nectarine cv. Super Queen (SQ) with the parallel sequence of the strain AP 15 of the 'Candidatus Phytoplasma mali' (16SrX-A). The phytoplasma infecting sweet cherry cv. Kordia (Kord) was most similar to the PD1 strain of the 'Candidatus Phytoplasma pyri' (16SrX-C). This is the first report of the occurrence of 'Ca. P. prunorum', 'Ca. P. mali' and 'Ca. P. pyri' in naturally infected stone fruit trees in Poland.

Evaluation of messenger plant activator as a preharvest and postharvest treatment of sweet cherry fruit under a controlled atmosphere

The preservation methods as an alternative to chemical control to prevent postharvest quality losses of sweet cherry were examined. The efficacy of preharvest and postharvest messenger (M) treatments on sweet cherry cv. ‘0900 Ziraat’ was tested under a controlled atmosphere in 2004 and 2005. The factors investigated included the separate or combined effect of low oxygen, high carbon dioxide and M on the quality and fungal pathogens of sweet cherries in a normal atmosphere (NA) and in a controlled atmosphere (CA). Cherries were placed at six different atmosphere combinations (0.03%:21% [NA, control], 5%:5%, 10%:5%, 15%:5%, 20%:5% and 25%:5% CO2:O2) at 0°C and 90% relative humidity for up to 8 weeks. Mass values were higher in cherries stored under NA compared with CA. Initial firmness was 1.45 kg and 1.41 kg in fruits without messenger (WM) and in M fruits, respectively; and was measured as 0.30–0.59 kg in WM and 0.57–0.95 kg in M at the end of the trials. The highest acidity and ascorbic acid values were recorded at the end of storage from the fruit stored under CA + M. The CA + M treatment proved the most effective with regard to delaying the maturity and preserving the fruit quality in sweet cherries during storage. Moreover, the CA + M treatments reduced the rotten fruit from 24.06% to 3.80% in cv. ‘0900 Ziraat’. Better fruit quality was obtained under CA + M compared with NA and CA. The fungi most frequently isolated from sweet cherries were Botrytis cinerea, Penicillium expansum, Monilinia fructicola, Alternaria alternata and Rhizopus stolonifer. It was concluded that sweet cherry cv. ‘0900 Ziraat’ could be stored successfully under CA (20%:5%) + M, and partially under CA (25%:5%) + M, conditions for more than 60 days. Thus, it is recommended that CO2 levels for sweet cherry storage can be increased above 15% with M.

Characterization of a flowering cherry strain of Cherry necrotic rusty mottle virus

The host range and complete nucleotide sequences of two Cherry necrotic rusty mottle virus (CNRMV) isolates (FC4 and FC5) infecting flowering cherry accessions imported from Japan are described. Of the plants tested, cherry, peach, apricot and almond became infected, but only sweet cherry cv. 'Canindex', Nanking cherry and apricot cv. 'Tilton' showed a mild foliar mottle. The genomic sequences of CNRMV-FC4 and CNRMV-FC5 are 8,430 and 8,429 nt in length, excluding the 3' poly (A) tail. They contain seven open reading frames encoding for a putative virus replicase, "triple gene block" proteins, a coat protein and two proteins with unknown functions. The two CNRMV-FC isolates share 96% identity in the genomic sequences, and their genome organizations are virtually identical to that of a German CNRMV isolate (CNRMV-GER). However, they differ from CNRMV-GER by 14% in the overall nucleotide sequence and 2% (ORF2) to 30% (ORF5a) in the derived amino acid sequences of individual gene products.

The effects of cytokinin types and their concentration on in vitro multiplication of sweet cherry cv. Lapins (Prunus avium L.)

Determination of the most optimal types and concentrations of plant growth regulators as medium constituents is one of the most important aspects of successful micropropagation, among other in vitro factors. With the aim of optimization of in vitro multiplication of sweet cherry cv. Lapins the effect of following cytokinins has been studied: benzyladenine (BA), isopentenyl adenine (2iP), kinetin (KIN) and thidiazuron (TDZ) at concentrations of 1, 2, 5, 10 and 15μM, combined with auxine, indole-3-butyric acid (IBA) at concentrations of 0, 0.5, 2.5 and 5μM. MURASHIGE and SKOOG (1962) was the basic medium used in all the combinations. The following multiplication parameters were monitored: multiplication index, length of axial and lateral shoots. Fresh and dry shoot weight (callus, stem and leaves – S + L) were determined. Some specific issues, such as colour, leaf and callus size, leaf roll, incidence of chlorosis or necrosis along with occurrence of rhizogenesis, i.e. roots unusual for this phase of micropropagation, were also monitored. The highest multiplication index as well as length of axial and lateral shoots was obtained on media with BA. Very poor multiplication, with large sized shoots and big leaves, was achieved on media with 2iP, TDZ and KIN, whereas in many combinations with 2iP, and particularly in those with KIN, rhizogenesis was induced. Obtained results suggest that the choice of cytokinins for the phase of multiplication of sweet cherry is limited to BA. For more rapid micropropagation, through joining rooting and multiplication phases, KIN and 2iP may be applied. The latter two may be also used to obtain sturdy shoots (elongation phase, prior to rooting).

POLLINATION, POLLEN TUBE GROWTH AND DETERMINATION OF SUITABLE POLLINIZER FOR SWEET CHERRY (PRUNUS AVIUM L.) CULTIVAR GHERMEZ REZAEIEH

Sweet cherry (Prunus avium L.) is one of the most important temperate fruits in the world. Most sweet cherry cultivars are self-incompatible and have usually problem with fertilization and fruit set, so they need suitable pollinizer for good fruit setting and commercial yield. The present study was carried out on sweet cherry cultivar Ghermez Rezaeieh as seed parent tree and Zarde daneshkadeh, Protiva, Sorati Lavasan, Haj-Yosefi and Meshkinshahr cultivars as pollen parent trees. Treatments (Pollens) were applied in randomized complete blocks design (RCBD) with three replicates. All laboratory and microscopic examinations of the collected samples were carried out in the Department of Horticultural Science, Tarbiat Modares University (TMU), Tehran, Iran and Controlled hybridization and pollination performed in the Seed and Plant Improvement Institute (SPII), collection orchard at Kamalabad, Karaj during 2004 and 2005 growing seasons. In order to determine the compatibility or incompatibility of various pollens on Ghermez Rezaeieh two methods were used: controlled pollination and examination of pollen tube growth with fluorescence microscopy. The results based on controlled pollination showed that MeshkinShahr and Protiva cultivars are compatible and Zarde daneshkadeh, Sorati Lavasan and Haj-Yosefi are incompatible cultivars with Ghermez Rezaeieh. The mean of fruit set in Ghermez Rezaehe cultivar with use of pollen grains of Zarde daneshkadeh, Protiva, Sorati Lavasan, Haj-Yosefi and Meshkinshahr were 0.54, 40.49, 0.24, ,0.80 and 61.36 percent respectively .The results also showed that sweet cherry cv. Ghermez Rezaeieh is a self-incompatible cultivar (fruit set=0) and it needs compatible and suitable pollinizer for fruit set. The results based on microscopic examinations showed that pollen tube of Meshkinshahr cultivar reached into the Ghermez Rezaeieh ovary flowers in 96 hours after pollination. These microscopic examinations and observations confirmed the obtained results from controlled hybridization in garden. In conclusion, Protiva and Meshkinshahr were selected as the best pollinizers for Ghermez Rezaeieh cultivar