Rootstock Research Articles

CRESCIMENTO DE CAFEEIROS ENXERTADOS CULTIVADOS EM SOLUÇÃO NUTRITIVA

The use of grafting in coffee, and give greater tolerance for nematodes, have shown influence on the growth of coffee, so the purpose of this study was to evaluate the growth of different varieties of Coffea arabica L. grafted into Apoata IAC 2258 ( Coffea canephora ). The experiment was installed in a greenhouse, using the method of cultivation in nutrient solution. It used a factorial 7 x 3 + 2, and seven cultivars of C. arabica L. (Palma II, Catucai 2SL, Oeiras MG 6851, Obata IAC 1669-20, Acaua, Topazio MG 1190 and Paraiso MG H 419-1), three types of seedlings (coffee cultivars grafted on ‘Apoata IAC 2258’, self grafted, meaning a cultivar was grafted on a rootstock of the same cultivar and no grafting) and two additional treatments (Apoata self grafted and Apoata no grafting). The technique of grafting did not disadvantage the development of seedling trees. Cultivars Acaua, Paraiso MG H 419-1 and Catucai 2SL had better perform when grafted. The development of the root system of the plants self-grafted and non-grafted seedlings was better then grafted seedlings. Cultivars Palma II, Obata IAC 1669-20 and Oeiras MG 6851have potential to promote the root system development similar to Apoata self-grafted seedlings.

Adventitious shoot regeneration from leaves of apple rootstock ‘Pingyitiancha’ (Malus hupehensis var. pinyiensis) and genetic fidelity of regenerated plantlets using SSR markers

Jin, W., Wang, Y. and Wang, H. 2014. Adventitious shoot regeneration from leaves of apple rootstock ‘Pingyitiancha’ (Malus hupehensis var. pinyiensis) and genetic fidelity of regenerated plantlets using SSR markers. Can. J. Plant Sci. 94: 1345-1354. Apple is one of the major fruit tree species in China, its cultivation area and total output rank first in the world. ‘Pingyitiancha’ (Malus hupehensis var. pinyiensis) is a widely used rootstock for apple cultivation in China. Several factors affecting leaf regeneration were investigated. In this study, a successful adventitious shoot regeneration protocol for this cultivar was established. ‘Pingyitiancha’ leaves were a suitable source of explants for regeneration of adventitious shoots. The optimal adventitious shoot regeneration protocol involved subculturing seedling leaves for 30-35 d. The optimum medium was Murashige and Skoog (MS) medium containing 2.0 mg L-1 thidiazuron and 0.2 mg L-1 indole-3-butyric acid. Explants with the abaxial surface in contact with the medium kept for 14 d in the dark showed the highest regeneration percentage of adventitious shoots of explants (100%), and produced an average of 3.6 shoots per regenerating explant. Shoots regenerated from leaves were rooted on half-strength MS medium containing 0.4 mg L-1 1-naphthalene acetic acid. The rooting percentage was 94.4%. Using SSR markers, all banding profiles from regenerated plantlets were monomorphic and same to those of the mother plant. It showed that the uniformity of the in vitro regenerated plantlets was maintained.

The JatrophaFT ortholog is a systemic signal regulating growth and flowering time

Jatropha curcas is being promoted as a new bioenergy crop in tropical and subtropical regions due to its high amount of seed oil and its potential capacity to grow on marginal land for biofuel production. However, the productivity of the plant is constrained by the unfavorable flowering time and inflorescence architecture, which render harvesting of seeds time-consuming and labor-intensive. These flowering-related traits have limited further widespread cultivation of Jatropha. We identified a Jatropha curcas homolog of Flowering locus T (JcFT) and demonstrated its function by genetic complementation of the Arabidopsis ft mutant. The JcFT expression level was found to be remarkably correlated with leaf age. Overexpression of JcFT in Jatropha reduced flowering time and altered plant architecture by producing more branches. Grafting experiments suggested that the earlyflowering and alteration of plant architecture traits were graft-transmissible. We also showed that the FT-overexpressing transgenic Jatropha can be used as a root stock for grafting of scions derived from other Jatropha. We generated early flowering transgenic Jatropha plants that accumulate higher levels of the florigen FT. Not only early flowering but also plant growth was affected in JcFT overexpression lines. More seeds can be produced in a shorter time frame by shortening the flowering time in Jatropha, suggesting the possibility to increase seed yield by manipulating the flowering time.

Significance of xylem water conductance for the compatibility of maté phenotypes (Ilex paraguarensis) for grafting

In this study the compatibility for grafting of root stocks and buds of three recognized leaf phenotypes of Ilex paraguarensis St. (mate) Hil. from south Brazil was investigated. Special regard was given to the anatomical structure and the sap flow in the secondary xylem of the grafted plants. Significant differences of the wood structure expressed in terms of vessel portion, vessel member length, and intervessel perforations were found in low compatible phenotypes, while highly compatible phenotypes had a very similar wood structure. In grafts of highly compatible phenotypes six months after grafting the water conducting system of root stocks and buds was strongly linked to each other, while in grafts of low compatible phenotypes the formation of connecting vessel elements was rare. In the first month after grafting the xylem sap flow in the buds of all grafts was significantly higher compared to their root stocks, while in the second month in grafts of highly compatible phenotypes, the water transport in the root stocks and in the buds was balanced. In contrast, in grafts of low compatible phenotypes even in the second month the water transport in the root stocks was lower compared to the buds causing the dieback of a high portion of these plants.

The effect of organic mulches and mycorrhizal substrate on growth, yield and quality of Gold Milenium apples on M.9 rootstock

Sas-Paszt, L., Pruski, K., Zurawicz, E., Sumorok, B., Derkowska, E. and Gluszek, S. 2014. The effect of organic mulches and mycorrhizal substrate on growth, yield and quality of Gold Milenium apples on M.9 rootstock. Can. J. Plant Sci. 94: 281-291. A 3-yr study was conducted to evaluate the effects of organic mulches and mycorrhizal substrate on growth and yield of apple cv. Gold Milenium grown on M.9 rootstock. Straw (rye), pine bark, conifer tree sawdust, compost (plant debris), cow manure, peat moss substrate (commercial), and mycorrhiza substrate (Mykoflor®, containing mycorrhizal fungi: Glomus intraradices, G. mosseae, G. etunicatum) were applied in spring of each year. All the applied treatments did not affect significantly the tree growth. Mulches did not have a positive effect on total soluble solids of the fruit and the number of fruits in different size categories. Only sawdust mulch significantly increased the number of fruit in size diameter class of 7.0-7.5 cm compared with the control. The u...

Detection of viruses in apples and pears by real time RT-PCR using 5′-hydrolysis probes.

Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV), Apple chlorotic leaf spot virus (ACLSV) and Apple mosaic virus (ApMV) are common in apples and pears and the main targets of virus elimination from propagation material. The objective of this work was to design primers and probes for a real time RT-PCR protocol for detection of the four above viruses. FAM/TAMRA-labeled probes and primers were designed by searching for highly conserved nucleotide regions in the coat protein gene of the four viruses. Infection levels in analyzed apple samples were 92.6, 96.4, 100 and 88% for ASGV, ASPV, ACLSV and ApMV, respectively. In pears, all pre-existing ASPV infections were detected. Viral infections were confirmed in a selection of commercial cultivars of apples and pear scions, and quince rootstocks, demonstrating the sensitivity and reliability of the designed primers and probes. Real time RT-PCR using 5'-labeled probes is suitable for checking sanitary quality as a routine test in certification programs.

English

In the recent times, there has been a reversed interest in the search of plant growth promoting endophytes (PGPE) for sustainable crop production. Mango is an economically important fruit crop, which is highly sensitive to saline environment. In the present study the importance of PGPR in growth promotion and their ability to elicit ‘induced systemic tolerance’ against abiotic (sodicity) stresses has been documented. Sixteen (16) putative of endophytic bacteria were isolated from sodicity tolerant polyembryonic mango root stock of GPL-3 and ML-4 from Shivari experimental farm, Central Soil Salinity Research Institute, Regional Research station, Lucknow, Uttar Pradesh, India. These endophytic bacteria were characterized using morphological and biochemical parameters and assessed for their plant growth promoting rhizobacteria (PGPR) traits like indole acetic acid (IAA) production, hydrogen cyanide (HCN) production, phosphate solubilization and siderophore production with 2.5 M NaCl concentration. The results based on specific biochemical characters revealed that the endophytic bacteria belonged to 14 different species and two uncultured organisms comprising five genera. Based on multifunctional properties under saline environment, four isolates were further selected to determine the PGP as vigor index of rice seedlings in pot culture experiments under saline sodic soils of pH 9.35 and EC 4.2. Of the bacteria tested, the isolate CSR-M-16 showed increased root and shoot length of rice followed by CSR-M-8, CSR-M-9 and CSR-M-6. The outcome of this research proves plausible practical applicability of these PGPB for crop production in saline sodic environment. Key words: Endophytes, salt tolerant, PGP bacteria, mango root stock, polyembryony.

Systemic movement of <i>Pseudomonas syringae</i> pv <i>actinidiae</i> in kiwifruit vines in New Zealand

Systemic movement of Pseudomonas syringae pv actinidiae (Psa) was investigated in inoculated potted kiwifruit vines in a greenhouse and in naturally infected mature vines in the orchard In the potted vine experiment trunks of 2yearold Actinidia chinensis Hort16A on the rootstock A deliciosa Bruno were woundinoculated with Psa After 151 days Psa was detected up to 95 cm from the point of inoculation Psa moved upwards and downwards within the trunks and through the scion and the rootstock at similar rates In the orchard experiments samples were taken from mature kiwifruit vines at intervals along the vines during autumn winter and spring Psa moved systemically throughout mature Hort16A and A deliciosa Hayward kiwifruit vines and was detected in symptomless tissues In both greenhouse and field situations Psa was not inhibited by the graft union and was able to move into the rootstock and down to the base of the vine

Fibrous Root Distribution in Blood Red Sweet Orange Trees under Semi- arid Irrigated Ecosystem

Fibrous root distribution pattern of mature trees of sweet orange cultivar Blood Red budded on rough lemon with her cleoptera and troyer citrange rootstocks were studied by root excavation method. The roots excavated from four radial distances i.e.0–75,75–150, 150–225 and 225–300 cm from the tree trunk and three depths i.e.0–15, 15–30 and 30–60 cm from the ground level indicated that fibrous root dry weight density and proportion of dry weight differed significantly at various depths and radial distances. Cleoptera has more feeder roots as compared to rough lemon and troyer. Feeder root dry weight density and dry weight proportion was almost the same between 0–15 & 15–30 cm depth and at deeper horizon there was significant decrease in all the root stocks. Approximately 70% of the total feeder roots in all rootstocks were within 0–30 cm depth i.e. intensive vertical development. The highest feeder root dry weight density was recorded at 0-75cm radial distance after that there was a sharp decrease. Troyer citrange, cleoptera and rough lemon contain about 65, 61 and 50% feeder roots up to 150 cm radial distance from the trunk. Hence, feeder roots, in troyer citrange and cleoptera may be exemplified as intensive lateral development. Rough lemon bears extensive lateral development as it has substantial amount of feeder roots at 150-225cm radial distance.

Role of grafting in cucurbitaceous crop s-A review

Due to limited availability of arable land and high market demand for off-season vegetables, cucurbits (plants in the family Cucurbitaceae) are continuously cultivated under unfavorable conditions in some countries. These conditions include environments that are too cold, wet, or dry, or are cool low-light winter greenhouses. Successive cropping can increase salinity, the incidence of cucurbit pests, and soil borne diseases like fusarium wilt caused by Fusarium spp. These conditions cause various physiological and pathological disorders leading to severe crop loss. Chemical pest control is expensive, not always effective, and can harm the environment. Grafting can overcome many of these problems. Some seed companies now offer watermelon transplants grafted on to squash or bottle gourd rootstocks, and some transplant facilities offer grafting services.

Effects of interstock (M9) length grafted onto MM106 rootstock on sylleptic shoot formation, growth and yield in some apple cultivars

Bu calismada 2003-2010 yillari arasinda, MM106 anaci uzerinde 15 ve 30 cm uzunlugundaki M9 ara anacinin Golden Delicious ve Granny Smith elma cesitlerinde fidanin dallanmasi uzerine etkisi ile vegetatif buyume ile toplam verim uzerine etkisi belirlenmistir. Sonuclar, ara anac yuksekliginin artmasi ile her iki cesitte fidan ve agac gelisiminin onemli olcude azaldigini ancak yan dallanmanin arttigini gostermistir. En uzun agac boyu Golden Delicious ve Granny Smith cesitlerinin kontrol grubunda sirasiyla 176.5 - 186.5 cm olarak, en kisa agac boyu ise ayni cesitlerde 30 cm’lik ara anac yuksekliginde sirasiyla 147.5 cm ve 162.6 cm olarak olculmustur. Kontrolde yan dal olusumu meydana gelmezken, yan dal sayisi 30 cm’lik ara anac yuksekliginde 3.67 (Golden Delicious) ve 5.33 (Granny Smith) bulunmustur. En yuksek toplam verim, 30 cm’lik ara anac yuksekliginden 21.77 kg agac-1 (Golden Delicious) ve 19.18 kg agac-1 (Granny Smith) elde edilmistir. Sonuclar, bodur M9 ara anacinin ozellikle surdurulebilir ve organik elma yetistiriciligi sistemlerinde buyumeyi azaltici, dallanma ve erken meyveye yatmayi ise tesvik etme potansiyelinin bulundugunu gostermektedir.

The Herbal Insecticides from Root Stock of Alocasia indica as Potential Sources for Control of Stored-Product Insect Pests

In the present study the insecticidal activity of organic extracts from root stock of Alocasia indica (Linn.) against three major important stored grain insect pest viz; rice weevil, Sitophilus oryzae; the lesser grain borer, Rhyzopertha dominica and the rust-red flour beetle, Tribolium castaneum is reported. The fumigant toxicity of hexane extract shows LC50 value 108.4 μg/l for adult T. castaneum, 96.2 μg/l for S. oryzae and 84.6 μg/l for R. dominica, respectively and toxicity was species specific. A concentration of 300 μg/l for a period of 72 h exposure resulted in 100% mortality of mixed age culture of these three species. An extended exposure period of 72 h has increased the rate of mortality in all three species. Further the results confirm that there are no significant differences between seed germination of control and treated grains. The study proved that efficacy of Alocasia indica when extracted with hexane is more effective when compared with other type of solvent extractions. The probable use of this extract as a bio fumigant is here with discussed.

EFFECT OF IRON DEFICIENCY ON ROOT FERRIC CHELATE REDUCTASE, PROTON EXTRUSION, BIOMASS PRODUCTION AND MINERAL ABSORPTION OF CITRUS ROOT STOCK ORANGE JASMINE (MURRAYA EXOTICA L.)

Three-week iron (Fe) deficiency stress experiments were conducted using two citrus root stocks, Fe-deficiency tolerant Orange Jasmine (OJ, Murraya exotica L.) and the sensitive Flying Dragon [FD, Poncirus trifoliata var. monstrosa (T. Ito) Swingle]. Root ferric chelate reductase activity and proton extrusion increased in OJ between 12 and 18 d of stress, whereas there was no change in FD. Dry weight of OJ roots increased in contrast to FD which decreased. The Mn content in OJ remained the same even under Fe stress. Zn content in OJ roots doubled while that of FD increased 4-folds. The shoot/root Fe accumulation ratio increased in OJ while it decreased in FD. OJ apparently has mechanisms for increasing root biomass, controlling Fe reutilization and regulating manganese (Mn) and zinc (Zn) absorption in response to Fe deficiency. These mechanisms could help maintain homeostasis under heavy metal stress, which would be useful for improved growth of economically important citrus species.

FIRST REPORT OF APPLE COLLAR ROT INCITED BY SCLEROTIUM ROLFSII IN TUNISIA

Sclerotium rolfsii Sacc. [teleomorph Athelia rolfsii (Curzi) Tu et Kimbrough] is a soil- borne polyphagous phytopatho- genic fungus characterized by prolific growth and ability to produce persistent sclerotia. In Tunisia, S. rolfsii has al- ready been reported on potato (Daami-Remadi et al., 2007) and olive (Boulila, 2001). In spring 2012, a sudden death of 2-year-old apple trees (Malus domestica) cv. Royal Gala grafted on MM106 rootstock was observed in an orchard near Tunis showing leaf chlorosis, root and collar rot. Isola- tions from necrotic wood on PDA medium, yielded consis- tent white fungal colonies, producing only sclerotia and no fruiting bodies or spores. Based on morphological charac- teristics, the fungus was tentatively identified as Sclerotium sp., then confirmed by sequencing the ITS region of rDNA. The obtained sequence (accession No. KF021301) matched the sequence of Athelia rolfsii (ATCC 201126). A pathoge- nicity test was performed on 2-year-old grafted apples of cv. Royal Gala in a glasshouse at 25-28°C and 80% relative hu- midity. Mycelial plugs of S. rolfsii were inoculated into the basal stem of 10 plants, whereas an equal number of non inoculated plants served as controls. Symptoms like those observed in the field developed in inoculated plants, but not in the controls, 35 days post inoculation. S. rolfsii was consistently re-isolated from infected wood tissues fulfill- ing Koch’s postulates. Apple collar tot (ACR) was originally described as apple southern blight in the USA and has also been reported in India, China, Israel and Italy (Corazza et al., 1999). To our knowledge this is the first report of ARC in Tunisia. The Tunisian Apple industry is mostly grown on MM106 rootstocks, and therefore, ACR represents a serious threat.

Response of Missouri and Yazdi peach seedling rootstocks to soil application of nitrogen in a nursery of Karaj, Iran

The effect of increasing soil nitrogen fertilization as ammonium sulfate or urea was studied on surface soil variable, mineral and leaf chlorophyll content, and some growth characters (leaf surface, shoot and root length, internodes length, diameter of shoot, dry weight of shoot and root) of 2 peach seedlings rootstocks (Missouri and Yazdi) grown on nursery of seed and plant improvements institute (SPII) in Karaj in the North west of Tehran (Capital of Iran). The results of the principle component analysis (PC) corresponding to soil data of implicated soil nitrogen fertilization have shown available soil potassium (Kava) was the most important parameter followed by soil phosphorus (Pava). The first components were more highly correlated with the studied variables than the second components and so on. According to the results, having high available soil potassium and phosphorus was more important than adding more of nitrogen fertilizer. Height growth of both seedling rootstocks correlated positively with available soil potassium and soil phosphorus. In conclusion, fertilizing Missouri and Yazdi seedling root stocks with 200 kg/ha sulfate ammonium seems to be the promising treatments under experiment conditions. Key words: Chlorophyll content, growth characters, Karaj, mineral and leaf surface, nursery, peach seedlings rootstocks, soil application of nitrogen.

EVALUATION OF THE SUSCEPTIBILITY OF DIFFERENT PRUNUS ROOTSTOCKS TO NATURAL INFECTION OF PLUM POX VIRUS-T

SUMMARY Plum pox virus (PPV) has been observed in Turkey since 1968, but was not widespread except in apricot and plum trees in home gardens and ornamental parks in restricted areas. Susceptibility of six different Prunus rootstocks to strain PPV-T was assessed under natural inoculum pressure in the Izmir-Aegean region during 2010-2011. Aphid populations were monitored from the first week of April to the middle of June by the stickyplant method one year after the rootstock plantation was established. Aphids collected from different rootstocks were tested individually by squash real-time RT-PCR and all rootstocks were regularly tested by DASI-ELISA. The largest aphid populations were observed at the end of May and the most abundant aphid species as averages over the two years were Myzus persicae (20.15%), Hyalopterus pruni (18.64%), Aphis craccivora (9.04%) and Aphis gossypii (8.36%). In 2011, the highest percentage of viruliferous aphids was found in M. persicae (34.78%), followed by H. pruni (32.50%), Macrosiphum euphorbiae (25.00%), A. gossypii (23.80%), A. spiraecola (12.50%) and A. craccivora (10.00%). Of the six Prunus rootstocks tested, only Nemaguard and Myrobalan 29C were infected by PPV-T, infection rate in 2010 being 6.0% (Nemaguard) and 4.0% (Myrobalan 29C). The infection rate increased to 16.0% for Nemaguard and 14.0% for Myrobalan 29C in 2011. However, the other rootstocks, Prunus marianna GF8.1, Docera6, GF677 and Garnem tested negative for PPV-T throughout 2011. PPV isolates obtained from naturally infected apricot trees (inoculum source) and from infected rootstocks in the experimental plot were characterized as PPV-T and had more than 99.5% nucleotide sequence identity.

The Influence of Seed Position on the Emergence Some Rootstocks by Lagenaria siceraria

The researches was conducted in the Laboratory for Protected Cultures of the ICDIMPH-Horting Bucharest. The observations were made during the growing season, in 2013 year. The experience was conducted in a rootstocks collection consisting from 3 hybrids F 1 by Lagenaria siceraria (Argentario, Macis, Achile). The research has aimed obtaining some rootstocks by cucurbits using different seeds positions, in order to establish technological dates to produce seedlings for grafting. The results show that at the studied hybrids the seed position has influenced the rootstocks emergence. The seed position is an important factor in the technology for production of L. siceraria rootstocks seedlings.

Results concerning the growth indicators of the cucumbers grafted seedlings.

The research was realized in the Laboratory of Protected Cultures of the ICDIMPH-Horting Bucharest, during the years 2008-2013. Were watched the growth of the cucumbers grafted seedlings. The biological material used was composed from grafted seedlings, using one scion, cucumbers F 1 hybrids (Mathilde) and three rootstocks – wild variety, F 1 hybrids (TZ148, Shintoza, Batora). From registration of the growth indicators has resulted a superior quality of the grafted planting material, compared with the normal seedlings. TZ148 rootstock has obtained the best results, followed by Shintoza, then Batora.

Long-distance transport of Gibberellic Acid Insensitive mRNA in Nicotiana benthamiana

BackgroundThe Gibberellic Acid (GA) signal is governed by the GAI (Gibberellic Acid Insensitive) repressor, which is characterized by a highly conserved N-terminal DELLA domain. Deletion of the DELLA domain results in constitutive suppression of GA signaling. As the GAI transcript is transportable in phloem elements, a Δ-DELLA GAI (gai) transgenic stock plant can reduce the stature of a scion through transport of gai mRNA from the stock. However, little is known about the characteristics of a scion on a gai stock.ResultsArabidopsis Δ-DELLA GAI (gai) was fused with a T7 epitope tag and expressed under the control of a companion cell-specific expression promoter, Commelina yellow mottle virus promoter (CoYMVp), to enhance transport in the phloem. The CoYMVp:Atgai-T7 (CgT) transgenic Nicotiana benthamiana exhibited a dwarf phenotype and lower sensitivity to GA enhancement of shoot stature. A wild-type (WT) scion on a CgT stock contained both Atgai-T7 mRNA and the translated product. Microarray analysis to clarify the effect of the CgT stock on the gene expression pattern in the scion clearly revealed that the WT scions on CgT stocks had fewer genes whose expression was altered in response to GA treatment. An apple rootstock variety, Malus prunifolia, integrating CoYMVp:Atgai moderately reduced the tree height of the apple cultivar scion.ConclusionsOur results demonstrate that Atgai mRNA can move from companion cells to sieve tubes and that the translated product remains at the sites to which it is transported, resulting in attenuation of GA responses by reducing the expression of many genes. The induction of semi-dwarfism in an apple cultivar on root stock harbouring Atgai suggests that long-distance transport of mRNA from grafts would be applicable to horticulture crops.

Natural infection of sweet cherry trees with Apple scar skin viroid.

Apple scar skin viroid (ASSVd) is a fruit-damaging pathogen that causes significant economic losses to pome fruit trees. In the context of a survey on fruit tree viroids in Greece, ASSVd was initially detected by RT-PCR in two sweet cherry trees of cv. Tragana Edessis in an apple orchard in Florina (Macedonia, Greece). This finding was confirmed by direct viroid sequencing of the amplified RT-PCR products. In order to verify this finding, we further examined four sweet cherry trees cvs Tragana Edessis and Biggareau Burlat, two sweet cherry trees of undetermined cultivar, and fifteen neighboring apple trees in the same orchard for possible infection with ASSVd. The viroid assay was done by tissue print hybridization using an ASSVd-specific DIG-labeled probe at stringent hybridization conditions and by RT-PCR using two different ASSVd-specific primer pairs. ASSVd was detected in the six sweet cherry trees, including symptomatic samples, but not in any of the 15 apple trees. Purified ASSVd-positive RT-PCR products from sweet cherries were sequenced either directly or after cloning into pGEM-T or pCR II plasmid vectors. Sixteen ASSVd sequences obtained from five trees were 327-340 nucleotide long and shared 96- 99% identity with ASSVd isolates from Indian apples. There was no cherry-specific nucleotide changes in the ASSVd sequences obtained. The viroid was graft transmitted successfully from cherry trees to cherry rootstocks and the newly developed rootstock leaves were ASSVd-positive by RT-PCR. To our knowledge, this is the first molecular and biological analyses of ASSVd infecting sweet cherry trees.