Sweet Cherry Rootstocks Research Articles

Sweet cherry rootstock breeding program at Beijing Institute of Forestry and Pomology

Sweet cherry rootstock breeding program at Beijing Institute of Forestry and Pomology

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.

Effects of exogenous indole-3-butyric acid and myo-inositol on in vitro rooting, vegetative growth and biochemical changes in leaves and roots in the sweet cherry rootstock MxM 14 using shoot tip explants

In the present study, the effects of indole-3-butyric acid (IBA) alone and in combination with myo-inositol under in vitro conditions on morphogenic and biochemical responses in the MxM 14 (Prunus avium × Prunus mahaleb) sweet cherry rootstock were investigated using shoot tips as explants. The best treatment that induced the better response for rooting in terms of root number per rooted explant (16.46), root length (23.12 mm), root fresh weight (0.372 g), root dry weight (0.037 g) and rooting percentage (100 %) was 9.84 μΜ IBA in the absence of myo-inositol. Thus, myo-inositol suppressed the positive effect of IBA on rooting. The simultaneous application of IBA and myo-inositol achieved the better response for shoots development regarding their length (22.5–25.6 mm) in relation to the control (15 mm). However, the optimum shoot biomass was obtained with 9.84 μΜ IBA resulting in a 4-fold increase in shoot fresh (0.455 g) and dry weight (0.045 g) compared to the control. Regarding biochemical parameters, it was shown that there is no evident relation between chlorophyll levels, endogenous leaf proline or carbohydrate content in both leaves and roots, and improvement of rooting and shoot biomass in the respective observed treatments. On the contrary, the enhancement of rooting and shoot biomass could be related to the elevated endogenous proline levels in roots. According to the results obtained, there may be a correlation between the augmented proline levels in both leaves and roots in the IBA + myo-inositol combination treatments and shoot growth of MxM 14 explants (i.e. microcuttings height). The survival percentage of the ex vitro MxM 14 plantlets was 93 %. An efficient protocol of in vitro rooting and vegetative growth for the cherry rootstock MxM 14 was established using IBA and myo-inositol which constitutes a very useful tool for future genetic transformation.

Effects of Different Sweet Cherry Rootstocks and Drought Stress on

Bitki yetiştiriciliğinde, kuraklık stresi, genotipik farklılık ve besin elementleri arasındaki ilişkiler önemlidir. Bu çalışmada 50 litrelik saksılarda yetiştirilen kirazın mineral beslenmesi (N, P, K, Ca, Mg, Zn, Mn, Cu) üzerine farklı anaçlar ve kuraklık stresinin etkilerini belirlemek amaçlanmıştır. Çalışmada, beş farklı (P. mahaleb, Mazzard, Gisela-6, MaxMa 14, CAB 6) anaç üzerine aşılı 0900 Ziraat kiraz çeşidi kullanılmıştır. Denemede kontrol (her sulamada eksik nem tarla kapasitesine getirilene kadar sulama) ve 3 farklı su seviyesi (tarla kapasitesinin % 25, % 50 ve % 75’i) olmak üzere dört farklı sulama uygulaması yer almıştır. Denemede evapotraspiraasyonla eksilen su dört günde bir tamamlanmıştır. Sonuç olarak, bitkilerin mineral beslenmeleri farklı anaç ve kuraklık stresinden etkilenmiştir. Genellikle kuraklık stresi koşullarında “Mazzard ve Gisela 6” anaçları “MaxMa 14” anacına göre daha fazla besin elementi konsantrasyonuna sahip olmuştur. Sonuçlar, kuraklık stresinin N, P, K, Ca, Mg, Zn, Mn ve Cu konsantrasyonlarını düşürdüğünü göstermiştir. Kuraklık stresinde, CAB 6 anacının beslenme performansına etkisi diğer anaçlara göre daha yüksek bulunmuş ve kısıtlı sulamadan etkilenmemiştir. Sonuç olarak, kuraklık stresi ve farklı anaçların kiraz yaprakları besin elementi konsantrasyonları üzerine etkisi önemli bulunmuştur

In Vitro Propagation Of ‘Gisela 5’ Rootstock As Affected By Mineral Composition Of Media And Plant Growth Regulators

Abstract The purpose of the presented study was to determine the best mineral composition of media and plant growth regulators in the micropropagation of the ‘Gisela 5’ (Prunus cerasus × P. canescens) dwarf sweet cherry rootstock. Nodal explants from young healthy shoots were excised and cultured on Murashige and Skoog medium without growth regulators. In vitro raised shoot tips were transferred to three culture media including Murashige and Skoog (MS), Driver and Kuniyuki (DKW) and Lloyd and McCown (WPM) containing benzyl adenine (BA) (0.5, 1 or 2 mg·l−1) in combination with kinetin (Kin) at 0 or 0.5 mg·l−1. WPM and DKW media were proving to be the most effective, resulting in a higher percentage of shoot multiplication and shoot number as compared to MS. BA in concentration 2 mg·l−1 resulted in the highest number of microshoots per explant (3.1). For rooting, 0, 0.5, 1 or 2 mg·l−1 indole-3-butyric acid (IBA) on MS, DKW and WPM media were tested. WPM medium containing 2 mg·l−1 IBA was most effective for rooting (93.7%) in comparison to MS (53.1%) and DKW (14.0%). Rooted plantlets were successfully hardened and established in pots.

Effects of different sweet cherry rootstocks and drought stress on nutrient concentrations

Relation between drought stress, genotypic differences and nutrients are important in plant growth. The aim of the study was to determine the effects of different sweet cherry rootstocks grown in 50-liter pots and drought stress on nutrient (N, P, K, Ca, Mg, Zn, Mn, and Cu) concentrations of leaves. In this study 0900 Ziraat sweet cherry variety grafted on five different rootstocks ( P . mahaleb , Mazzard, Gisela-6, MaxMa 14, CAB 6) were used. Four irrigation treatments (control or 100%, 75%, 50%, and 25% and of the field capacity) were used and irrigation intervals were four days in the study. As a result, mineral concentrations of leaves were changed with both rootstocks and drought stress treatments. In general, “Mazzard and Gisela 6” sweet cherry rootstocks had higher nutrient concentrations than “MaxMa 14” under drought stress conditions. The results showed that drought stress reduced the concentration of N, P, K, Ca, Mg, Zn, Mn, and Cu concentrations. CAB 6 rootstock was not affected by water deficiencies and had higher performance on nutrition than the other rootstocks under drought stress conditions. In conclusion, drought stress and rootstocks have substantial effects on nutrient concentrations of sweet cherry leaves.

Rapid Propagation of Sweet and Sour Cherry Rootstocks

The paper presents a protocol for micropropagation of Prunus sp. rootstocks included in the sweet and sour cherry breeding program. Germplasm diversity for rootstock breeding derives from natural populations, where conditions and biological vectors for systematic infection with viral diseases are constantly present. The establishment of aseptic culture depends primarily on the explant type, as all selections were collected from natural habitat. For nearly all investigated selections, dormant buds were the favored source, due to enabling rosette initiation in more than 58% cases. In P. cerasus L. selections, 100% contamination was noted when shoot tips were used as an explant source. Significant influence of the double-phase medium on the number and height of multiplied shoots was observed in the standard cherry rootstock, ‘Gisela 6’. For P. fruticosa Pall., selection ‘SV1’ and ‘SV2’, and P. cerasus ‘D6’ selection, the double-phase medium also had a significant effect on the height of multiplied shoots, when compared to solid DKW (Driver and Kuniyuki Walnut) medium. Genetic variability of selections within the investigated species resulted in variable plant rooting success. Adding Fe-EDDHA (Ethylenediamine di-2-hydroxy-phenyl acetate ferric) in the 200 mg l-1 concentration to the rooting medium significantly enhanced the percentage of rooted plants. The highest rooting percentage was noted for ‘Gisela 6’ and ‘D6’ genotype at 1 mgl-1 IBA (indole-3-butyric acid), while 0.8 mgl-1 was the optimum concentration for P. mahaleb L. ‘M1’ selection. P. fruticosa genotypes required significantly higher IBA concentration for rooting (2.5 and 3.5 mg l-1).

Rapid Propagation of Sweet and Sour Cherry Rootstocks

The paper presents a protocol for micropropagation of Prunus sp. rootstocks included in the sweet and sour cherry breeding program. Germplasm diversity for rootstock breeding derives from natural populations, where conditions and biological vectors for systematic infection with viral diseases are constantly present. The establishment of aseptic culture depends primarily on the explant type, as all selections were collected from natural habitat. For nearly all investigated selections, dormant buds were the favored source, due to enabling rosette initiation in more than 58% cases. In P. cerasus L. selections, 100% contamination was noted when shoot tips were used as an explant source. Significant influence of the double-phase medium on the number and height of multiplied shoots was observed in the standard cherry rootstock, ‘Gisela 6’. For P. fruticosa Pall., selection ‘SV1’ and ‘SV2’, and P. cerasus ‘D6’ selection, the double-phase medium also had a significant effect on the height of multiplied shoots, when compared to solid DKW (Driver and Kuniyuki Walnut) medium. Genetic variability of selections within the investigated species resulted in variable plant rooting success. Adding Fe-EDDHA (Ethylenediamine di-2-hydroxy-phenyl acetate ferric) in the 200 mg l-1 concentration to the rooting medium significantly enhanced the percentage of rooted plants. The highest rooting percentage was noted for ‘Gisela 6’ and ‘D6’ genotype at 1 mgl-1 IBA (indole-3-butyric acid), while 0.8 mgl-1 was the optimum concentration for P. mahaleb L. ‘M1’ selection. P. fruticosa genotypes required significantly higher IBA concentration for rooting (2.5 and 3.5 mg l-1).

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Agrobacterium tumefaciens-mediated transformation of sour chgahtvy (Prunus cerasus L.) "Montmorency" and sweet cherry rootstocks "Gisela 6" and "Gisela 7" (P. cerasus × P. canescens) is described. Briefly, leaf explants from in vitro shoots are cocultivated with A. tumefaciens either directly (for "Gisela 6" and "Gisela 7") or after pretreatment (for "Montmorency") on cocultivation medium; selection and regeneration of transformed shoots are carried out on selection medium containing 50 mg/L kanamycin (Km) and 250 mg/L timentin (or cefotaxime) for 3-5 months. In this protocol, the optimal media for shoot proliferation and shoot regeneration from leaf explants are genotype dependent.

Experiences with Mazzard and Colt sweet cherry rootstocks in Serbia which are used for high density planting system under heavy and acidic soil conditions

From 2008 to 2013 we investigate impact of Mazzard seedlings and Colt rootstock on tree growth, precocity, productivity, gross profit, fruit quality and leaf nutrients level of seven sweet cherry cultivars which are grown at Cacak region (Serbia) on heavy and acidic soil in high density planting system (HDP). Results showed that most of the evaluated traits significantly varied between rootstock and among cultivars. Thus, Mazzard induced higher tree vigor, yield performances, gross profit, flesh rate, fruit acidity, and leaf P and Mn levels, whereas Colt induced higher fruit weight, fruit dimensions, size and shape values, stone weight, ripening index and leaf N, Ca, Mg, Fe and Zn amounts. Regarding cultivars, ‘Stark Hardy Giant’ (‘SHG’) had the lowest tree vigor on both rootstocks, whereas the highest was induced by ‘New Star’ on Mazzard, and by ‘Summit’ and ‘Lapins’ on Colt. Generally, the highest values of yield attributes and financial results were found in ‘Sunburst’ on Mazzard and ‘SHG’ on Colt, whereas ‘New Star’ had the poorest. ‘New Star’ on both rootstocks, ‘June Early’ on Mazzard, and ‘Lapins’ on Colt were cultivars with the better fruit weight and other physical traits, whereas ‘Hedelfinger’ had higher soluble solids content (SSC) and acidity on both rootstocks as compared with others. ‘New Star’ grafted on Mazzard and ‘Lapins’ on Colt showed a tendency to promote higher RI. Cherries of trees grafted on Colt showed higher capacity to accumulate leaf N, Ca, Mg, Fe and Zn, whereas leaf of cherries on Colt had higher P and Mn amounts. High variability among cultivars regarding leaf nutrients content was found. Both rootstocks and all cultivars on them exhibited excessive leaf N and Cu levels, and high insufficiency of other leaf macro- and micronutrients. Colt showed better balanced nutritional values for macronutrients, whereas rootstock impact on this trait for micronutrients was not significant. ‘SHG’ on both rootstocks, in general, is the cultivar with the best balanced nutritional values as compared to others.

Soil sterilisation and plant growth-promoting rhizobacteria promote root respiration and growth of sweet cherry rootstocks

Soil microorganisms play important roles in the plant-soil ecosystem, and plant growth-promoting rhizobacterium (PGPR) promotes plant growth through several mechanisms. To investigate the benefits of PGPR for root functions such as respiration, we used the plant model Cerasus sachalinensis Kom., in which root respiration provides a sensitive functional indicator to demonstrate the effect of soil sterilisation (SS) and inoculation with the PGPR Staphylococcus sciuri ss sciuri after SS on seedling root respiration and growth. Root respiration increased in the presence of PGPR inoculation alone, whereas Embden–Meyerhof–Parnas pathway activity decreased due to reduced phosphofructokinase and pyruvate kinase activities. Although cytochrome c oxidase activity decreased and alternative oxidase activity increased, only slight changes were observed in growth indicators such as seedling height. However, SS and PGPR inoculation after sterilisation reduced soil microbial biomass carbon and reduced root respiration. Pyruvate kinase activity as well as plant height and leaf number increased, thus promoting plant growth. Thus, we conclude that SS and PGPR inoculation altered enzymes activities, root respiration and plant growth of cherry rootstocks. The effects of microbial inoculation were altered by SS.

Microsatellite high-resolution melting (SSR-HRM) analysis for identification of sweet cherry rootstocks in Greece

Sweet cherries can be grafted onto a wide range of rootstocks belonging to the genus Prunus. The identification of sweet cherry rootstocks using morphological traits is almost impossible particularly during the dormant season, yet it is very important for the grower to know exactly the rootstock as this has a major influence on cultivar performance and agricultural practices. However, DNA-based molecular analysis carried out on actively growing shoot tips, leaves or dormant buds provides a good opportunity to reliably distinguish the rootstocks. Herein, we have integrated high-resolution melting (HRM) analysis, coupled with five simple sequence repeat (SSR) markers, in order to facilitate the identification of the most popular sweet cherry rootstocks in Greece. The five SSR loci used were highly informative and generated a unique melting curve profile of microsatellites for each of the six sweet cherry rootstocks tested. In particular, one marker, BPPCT002, with six HRM profiles was sufficient to discriminate all the sweet cherry rootstocks studied, highlighting its potential use for rootstock identification. Hence, this assay provided a flexible, cost-effective and closed-tube microsatellite genotyping method well suited to sweet cherry rootstock identification.

THE EFFECT OF ROOTSTOCK AND SPACING ON THE GROWTH AND YIELD OF 'KÁNTORJÁNOSI 3' SOUR CHERRY VARIETY IN INTENSIVE ORCHARD

In our trial eight different varieties of sweet and sour cherry rootstocks were examined in three different spacing, what was carried out in Experimental and Research Farm of Corvinus University of Budapest. The aim was to find rootstocks with drought tolerance in different vigorous for the ‘Kantorjanosi 3’, which a wide-spread sour cherry variety at Hungary. The rootstocks were tested (P. mahaleb: ‘CEMA’ and ‘Korponay’ seedlings, ‘SL 64’, ‘Bogdany’ and ‘Magyar’; P. fruticosa: ‘Prob’; Prunus hybrids: ‘Colt’ and ‘Pi-Ku 2’ vegetative propagated) in variant spacing (4x2,5; 4x2; 4x1,5 m). Trees were formed to slender spindle, what is suitable for modern fruit growing. Our results show that this type of crown can be applied at medium and strong vigorous rootstocks in different spacing. In extensive condition, large spacing (4x2-2.5 m) with strong vigorous rootstocks (Prunus mahaleb varieties) are recommended. ‘Magyar’ is also suitable under these conditions, and the spacing can be reduced to 4x1.75 m. The vigour of ‘Prob’ is not enough to the applied spacing. Under these conditions, it is difficult to keep the slender spindle form. Trees on these rootstocks with Zahn-spindle form in higher density could be efficient with modern irrigation, fertilization and training system. The ‘Prob’ rootstock resulted one of the best fruit size. Based on our results we do not recommend for ‘Kantorjanosi 3’ ‘Colt’ and ‘Pi-Ku 2’. The branches died and leaves turned yellow on ‘Pi-Ku 2’. ‘CEMA’ and ‘Korponay’ with strong vigorous gave better yield. Medium vigorous ‘Magyar’ was also suitable in higher tree density. Compared the data we can see that using larger spacing increases the yield significantly. On the other hand the specific yield index does not show significantly difference at the different spacing. Summarizing our results we can state that increasing the density in the orchard, the yield does not decrease significantly. We can reduce spacing as long as the vigorous of rootstocks-scion combination can allow it.

Genetic relationships among Prunus rootstocks for sweet cherry (Prunus avium L.) cultivars

Sweet cherries can be grafted on a wide range of rootstocks belonging to Prunus avium, Prunus cerasus, Prunus mahaleb, Prunus angustifolia or hybrids of different Prunus species. Identification of Prunus rootstocks using morphological traits is almost impossible particularly during the dormant season. However, molecular analysis carried out on actively growing shoot tips, leaves or dormant buds provides good opportunity to reliably distinguish rootstocks. In this study, DNA was extracted from the leaves of a total of 184 sweet cherry rootstock candidates belonging to P. avium L., P. cerasus L., P. mahaleb L. and P. angustifolia L. previously selected from the north-western part of Turkey. The rootstock candidates were tested with ten simple sequence repeat (SSR) primers, developed for the Prunus genus. The primers successfully identified all rootstock candidates. The results showed that the number of alleles per locus ranged from 10 (UDAp-401, UCD-CH21 and CPSCT010) to 20 (UCD-CH31) with an average of 13.3 alleles per locus, indicating that the SSRs were highly informative. Unweighted Pair-Group Method with Arithmetic mean analysis demonstrated that P. avium accessions are closely related to P. cerasus. The reference rootstocks were clustered with their associated botanical species.

Peroxidase isozyme profiles in some sweet cherry rootstocks and ‘0900 Ziraat’ cherry variety

This study was carried out on one- year old trees of ‘0900 Ziraat’ variety grafted onto Kus kirazi, Kara idris, Sari idris, MaxMa 14, MaxMa 60 and Gisela 5 in order to determine their compatibility. For this purpose, peroxidase isoenzyme bands were determined with polyacrylamide gel electrophoresis (PAGE). Saplings were grafted at the beginning of September with ‘T’ budding. Bark samples were taken before and 12 months after the grafting. Barks were removed by using a razor blade 4 cm above and below the graft union and graft zone. Analysis of profiles revealed isoperoxidases bands Rf = 0.39 band A and Rf =0.42 band B that were both on scion and rootstocks. Peroxidase profiles are found similar in scion and rootstocks. Key words : Graft compatibility, peroxidase, cherry, PAGE.

Melatonin promotes adventitious root regeneration in in vitro shoot tip explants of the commercial sweet cherry rootstocks CAB‐6P (Prunus cerasus L.), Gisela 6 (P. cerasus × P. canescens), and MxM 60 (P. avium × P. mahaleb).

The objectives of this study were to test the effects of melatonin (N-acetyl-5-methoxytryptamine), a natural compound of edible plants on the rooting of certain commercial sweet cherry rootstocks. Shoot tip explants from previous in vitro cultures of the cherry rootstocks CAB-6P (Prunus cerasus L.), Gisela 6 (P. cerasus × P. canescens), and M × M 60 (P. avium × P. mahaleb) were included in the experiment. The effect of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) alone or in combination with melatonin was tested concerning their rooting potential. Seven concentrations of melatonin (0, 0.05, 0.1, 0.5, 1, 5, and 10 μM) alone or in combination with 5.71 μM of IAA or 4.92 μM of IBA were tested. For each rootstock, 21 treatments were included. The explants were grown in glass tubes containing 10 mL of substrate. The parameters measured include rooting percentage, number of roots per rooted explant, root length, and callus formation. The data presented in this study show that melatonin has a rooting promoting effect at a low concentration but a growth inhibitory effect at high concentrations. In the absence of auxin, 1 μM melatonin had auxinic response concerning the number and length of roots, but 10 μM melatonin was inhibitory to rooting in all the tested rootstocks. The final conclusion of this experiment is that exogenously applied melatonin acted as a rooting promoter and its action was similar to that of IAA.

Carbohydrate profiles in the graft union of young sweet cherry trees grown on dwarfing and vigorous rootstocks

In composite (scion–rootstock) dwarfing fruit trees, an overgrowth at the graft union is often observed, the severity of which is correlated with degree of dwarfing. The graft union of dwarfing sweet cherry ( Prunus avium L.) rootstocks may limit soluble sugar transport or starch mobilization, leading to localized accumulation. Soluble sugars and starch were measured in the tissues surrounding the graft union of young ‘Rainier’ (2002) and ‘Lapins’ (2003) sweet cherry trees on ‘Gisela 5’ (‘Gi 5’; dwarfing) and ‘Colt’ (vigorous) rootstocks. Separate rootstock shank, rootstock, graft union, and scion tissues were analyzed for both starch and soluble sugar content throughout the growing season in both years. Starch concentrations did not vary among locations within the graft union for ‘Rainier’ on either the dwarfing or vigorous rootstock, or for ‘Lapins’ on the dwarfing stock. However, for ‘Lapins’ on ‘Colt’, starch was highest in the rootstock shank and declined vertically (rootstock shank ≫ rootstock > union > scion). Soluble sugar concentrations were generally similar to or higher in scions on ‘Gi 5’ than on ‘Colt’, and were similar to or lower in the rootstock and rootstock shank on ‘Gi 5’ than on ‘Colt’. Results suggest that rootstock has a significant effect of localized accumulations of carbohydrates above and within the graft union of ‘Gi 5’ and below the graft union of ‘Colt’.

Response of the cherry rootstock to water stress induced in vitro

The in vitro response of sweet cherry (Prunus cerasus × P. canescens) rootstock Gisela 5 to increasing water deficit in the culture medium was studied. Water stress induced by the incorporation of 1, 2 and 4 % polyethylene glycol (PEG-8000) into the Murashige and Skoog medium was applied for 6 weeks. PEG-induced water stress reduced shoot dry mass, length, water content and relative chlorophyll content. Water stress also induced leaf necrosis without causing loss of viability in the explants. The increase in malondialdehyde content indicated oxidative stress. The activities of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POX) and glutathione reductase (GR) were also significantly elevated. The concentrations of K, Ca, Fe and Mn of shoots were decreased.

Responses of the cherry rootstock to salinity in vitro

The in vitro response of sweet cherry rootstock Gisela 5 (Prunus cerasus × Prunus canescens) to increasing concentrations of NaCl (0, 50, 100 and 150 mM) in the Murashige and Skoog culture medium was studied. Induced salinity reduced growth and chlorophyll content in shoots but had no effect on water content. The increase in malondialdehyde content indicated that salinity induced oxidative stress which was accompanied with the visible symptoms of salt injury in the shoots. Antioxidant enzymes, such as superoxide dismutase, ascorbate peroxidase, peroxidase, catalase, and glutathione reductase were also significantly elevated. Although no change was observed in the Cl concentration, Na concentration of shoots significantly rose and NaCl treatments impaired K, Ca and Mg nutrition and induced imbalance in K:Na and Na:Ca ratios.

Results of an orchard trial with new clonal sweet cherry rootstocks established at Holovousy and evaluated in the stage of full cropping

Ten clonal dwarf or semi-dwarf rootstocks were evaluated in a trial that was established in the spring of 1999 at Holovousy. Lapins cv. was used as a scion tester for all these rootstocks; five of them were tested also by Regina cv. Among the new rootstocks G 195/5 was evaluated as the most promising for Lapins cv. The highest rate of mortality and symptoms of poor scion compatibility with Lapins cv. were observed on Weiroot 53 and Weiroot 158. The most vigorous of the tested rootstock was G 497/8 followed by Gisela 7 and Gisela 4. Intermediate vigour was recorded on trees on G 154/7, P-HL-A, Gisela 3 and Tabel Edabriz. The least vigorous were G 195/20, Weiroot 158 and Weiroot 53. The highest accumulated yield per hectare of the Lapins cv. (21.2 tons) was harvested from Gisela 7 rootstock. With Lapins cv. higher yield efficiencies were calculated for P-HL-A, G 195/20 and Tabel Edabriz. In the case of the Regina cv. the highest yield efficiency was on Gisela 7. The mean fruit weight of the Lapins cv. had a span from 8.2 g (Weiroot 53) to 9.7 g (G 195/20). With the Lapins cv. less fruit cracking was observed on fruits from Tabel Edabriz and Gisela 7. Significant differences between tested rootstocks were found also at the time of tree flowering and ripening.