This study evaluated the agronomic performance of 15 plum cultivars grafted on both P. cerasifera and 'Wangenheim Prune' (P. domestica) seedling rootstocks over nine years at the Lithuanian Research Centre for Agriculture and Forestry. Trees on P. cerasifera were planted 4.5 m & times; 2.5 m apart, while those on 'Wangenheim Prune' were 4 m & times; 1.5 m apart. On average, trees on 'Wangenheim Prune' developed 23% smaller trunk diameters and produced 42% less pruning mass than those on P. cerasifera yet demonstrated higher yield efficiency, except for the 'Valor' cultivar, which performed better on P. cerasifera. Mean plot yield was about 40% higher on 'Wangenheim Prune'. Based on productivity, survival, and fruit quality, the most promising cultivars for Nordic climates are '& Ccaron;a & ccaron;anska Najbolja' and 'Jubileum' on 'Wangenheim Prune', while 'Valor' was productive on both rootstocks. Leaf nutrient analyses revealed rootstock-dependent differences: leaves on P. cerasifera contained more P, K, Ca, and Mn, whereas Mg, Cu, and Zn were higher on 'Wangenheim Prune'. Regardless of rootstock, trees grown in calcareous, high-pH soils were deficient in Fe and Mn.

Finding safe and efficient plant protection measures is one of the major challenges in horticulture. This study evaluated the biological effects of the Thymus vulgaris essential oil and of Bacillus halotolerans and B. velezensis bacterial mixture on strawberry growth and fruit quality properties, as well as on Botrytis cinerea severity. The experiment was conducted in a high-tunnel greenhouse with the strawberry cv. Sonsation. Treatments: (1) Control-untreated; (2) Bacteria-with Bacillus halotolerans and B. velezensis, four times during flowering; (3) Thyme I-T. vulgaris essential oil (EO), four times during flowering; (4) Thyme II-T. vulgaris EO, four applications supplemented by three additional applications during fruit ripening; (5) Biofungicide I-Bacillus subtilis QST 713, four times supplemented by three applications; (6) Biofungicide II-Clonostachys rosea J1446, four times during flowering. In the first year (2023), the highest total yield was observed in Thyme II, and in the second year (2024), the highest total yield was observed in Thyme I. The results did not reveal any visual phytotoxic effect on plant leaves. The average fruit diameter increased from 28 mm up to 31 mm in 2023 and from 35 mm to 39 mm in 2024. The average soluble solids content increased from 9.4 to 11.4 °Brix in 2023 and from 7.2 to 7.7 °Brix in 2024. The highest ascorbic acid content in 2023 was observed in Biofungicide II and Biofungicide I treatments, respectively, 79.9 mg % and 75.4 mg %. Similarly, in 2024, the highest ascorbic acid content was observed in Bacteria, Biofungicide I, and Biofungicide II treatments-39.3-40.2 mg %. In vitro, the lowest B. cinerea severity on strawberry leaves in 2023 was recorded in Thyme I and Thyme II treatments (~6-7%), while in 2024, the severity in these treatments was higher -20-22%. Thyme treatment showed a stable reduction in B. cinerea on leaves in vitro over both years.

Alternative plant protection methods should be promoted to mitigate the dangers and consequences of using chemical pesticides, ensuring a safe environment and protecting human health (Directive 2009/128/EC). One of the objectives of the EU organic production action plan is to provide substitutes for plant protection methods, decrease the adverse effects on the environment, and promote the diversity of living organisms. The use of synthetic and non-organic chemicals has significantly expanded, damaging human health and the environment. This study aimed to evaluate alternative plant protection solutions for the improvement of the strawberry cv. Elsanta plant's generative development, yield, fruit quality, and biochemical composition. The two-year strawberry experiment conducted in a tunnel greenhouse included chemical and biological means (Bacteria and Thyme preparations). The experiment randomised a block design with four replicates and 32 plants per replicate. The treatments were conducted at the 10% flowering state (BBCH 61-65), every 7-10 days (a total of four times): (1) Control, (2) Chemical, (3) Bacteria, and (4) Thyme. We evaluated the yield, fruit weight, size, number of leaves, crowns, flowers, inflorescences, fruit firmness, soluble solids, and Vitamin C. The highest fruit weight at the first picking was in the Bacteria treatment. The number of rotten fruits was similar after all treatments. Additionally, they were firmer and bigger in size but had a smaller soluble solids content. The strawberry ascorbic acid and soluble solids content (Brix %) showed significant variation. The highest ascorbic acid concentration in the fruit was after the Thyme application (45.06%). Our study showed that alternative plant protection measures can reduce the use of chemical fungicides and maintain proper fruit quality.

Sour cherry (Prunus cerasus L.) is a deciduous tree belonging to the Rosaceae Juss. family. Cherry leaves are an underutilized source of biologically active compounds. The aim of this study was to determine the composition of the phenolic compounds, as well as the total antioxidant activity, in leaf samples of P. cerasus cultivars and to elucidate the cultivars with particular phytochemical compositions. The phytochemical profiles of P. cerasus leaves vary significantly in a cultivar-dependent manner. The total content of identified phenolic compounds varied from 8.254 to 16.199 mg/g in the cherry leaves. Chlorogenic acid ranged between 1413.3 µg/g (‘North Star’) and 8028.0 µg/g (‘Note’). The total content of flavonols varied from 4172.5 µg/g (‘Vytenu zvaigzde’) to 9030.7 µg/g (‘Tikhonovskaya’). The total content of identified proanthocyanidins varied from 122.3 µg/g (‘Note’) to 684.8 µg/g (‘Kelleris’). The highest levels of phloridzin (38.1 ± 0.9 µg/g) were found in samples of ‘Molodezhnaya’, while the lowest level of this compound was determined in the leaf samples of ‘Turgenevka’ (6.7 ± 0.2). The strongest antiradical (138.0 ± 4.0 µmol TE/g, p < 0.05) and reducing (364.9 ± 10.5 µmol TE/g, p < 0.05) activity in vitro was exhibited by the cultivar ‘Vytenu zvaigzde’ cherry leaf sample extracts. ‘Kelleris’, ‘Note’, and ‘Tikhonovskaya’ distinguish themselves with peculiar phytochemical compositions.

Six sweet cherry cultivars and two advanced selections of Gisela 5 rootstock were tested in 2015–2021 at the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry. Fruit trees were planted at distances of 4.5 × 2.5 m and trained as spindles. Orchard floor management included frequently mown grass in alleyways with herbicide strips along tree rows. Cultivars ‘Mindaugė’ and ‘Irema BS’ were the most vigorous at the end of the seventh leaf. Their trunk diameter achieved 11.6 cm. The ‘Merchant’ cultivar had the smallest trunk diameter—9.3 cm. The average yield in 2018–2021 ranged from 2.75 t/ha for ‘Vega’ to 8.73 t/ha for ‘Regina’. Cultivars ‘Regina’, ‘Sunburst’, ‘Irema BS’ and ‘Merchant’ had the highest cumulative yield efficiency of 0.440–0.503 kg/cm2 with respect to the trunk cross-section area (TCSA). The least productive cultivar ‘Vega’ produced fruits of the highest average weight—9.9 g. Fruits of ‘Regina’ and ‘Sunburst’ were large as well—8.8–9.1 g. ‘Irema BS’ fruits had the highest soluble solids content (SSC)—20.2%. The lowest SSC was recorded in ‘Merchant’ and ‘Sunburst’ fruits—14.7–15.8%. The yield of advanced selection, No. 102, equaled to the yield of cv. ‘Regina’. No. 102 had a high fruit weight, and fruits were distinguished by attractiveness and taste.

Nutrient uptake and transport depend on the root system of a tree. Various apple rootstock genotypes may interact fruit tree nutrition. In 2017, two multi-location apple rootstock trials were established at 16 sites in 12 European countries. The evaluations are performed by members of the EUFRIN (European Fruit Research Institute Network) Apple & Pear Variety & Rootstock Testing Working Group. Following rootstocks are included in the tests: G.11, G.41, G.202 and G.935 (US), EM_01, EM_02, EM_03, EM_04, EM_05 and EM_06 (UK), 62-396-B10((R)) (Russia), P 67 (Poland), NZ-A, NZ-B, NZ-C and NZ-D (New Zealand) and Cepiland-Pajam((R))2 as control. The effect of rootstocks on the mineral content of leaf and fruit was studied at the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry in 2019-2020. The leaf and fruit mineral concentration of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and leaf mineral content of copper (Cu), zinc (Zn), iron (Fe), manganese (Mn) and boron (B) were measured. Significant rootstock effect was established on leaf P, Mg, Zn, Mn, B, and fruit Ca and Mg content. Rootstocks EM_01 and G.41 were the most efficient in leaf mineral uptake, while G.935 had the lowest content of all leaf macro nutrients. Rootstocks EM_06 and P 67 were the most efficient in fruit mineral uptake, while EM_02 had the lowest content of three nutrients. Current research reveals differences among rootstocks and their capacity to absorb separate minerals and enables creation of rootstock specific nutrition management.

Modern apple growing requires relatively often orchard replacement due to release of superior cultivars or introduction of new growing technologies. Most of intensive apples orchards are established in the same site where apple trees were cultivated for a long period. Continuous cultivation of the same crop causes stress to plants and often leads to abnormal plant development and decreased productivity what is known as apple replant disease (ARD). Due to ban of chemical soil disinfection, other strategies how to overcome ARD must be developed. Rootstock is becoming to be one of the most important factors to solve this problem and one of the targets of new rootstock breeding programs is rootstock resistance or tolerance to ARD. Different origin and genetic background of rootstocks led to suggest that their adaptiveness to replanted soil will be different. EUFRIN (European fruit research institutes network) Apple and pear cultivar and rootstock testing group established replant trials in several European countries where new apple rootstocks from USA, Great Britain, Poland and Russia are tested. Current paper presents results of the trial performed at the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry in 2017-2021. On average of all rootstocks apple trees planted in the fresh soil were by 35% more vigorous and gave 71% higher yield. After the evaluation of tree growth and productivity characters rootstocks 'G.41' and 'G.11' were the most tolerant to ARD. Trees on rootstocks 'G.935, 'Cepiland-Pajam (R) 2' and 'EM_02' had significantly lower yields in replant soil, while tree growth was most stunted on '62-396-B10 (R)' and 'EM_02'.

The study was performed with apple cultivar 'Rubin' grafted onto dwarf 'P60' rootstock at the experimental orchard of the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry, between 2016 and 2020. The orchard was planted in 2010. Planting distances were 1.25x3.5 m. Seven treatments of tree vigour control were established, including combinations of mechanical pruning, tree trunk incision and application of prohexadione-calcium (Pro-Ca). The strongest growth was recorded for the control treatment, where slender spindle trees were maintained manually. Significantly, the shortest shoots grew where mechanical pruning was applied. A tendency for higher yield was recorded for mechanical pruning treatments. Trunk incision and summer pruning exhibited significantly lower fruit mean weight and diameter. Multiple applications of Pro-Ca increased fruit weight. Less colored fruits were obtained for mechanical pruning treatments.

Modern apple orchard systems should guarantee homogeneity of fruit internal and external qualities and fruit maturity parameters. However, when orchards reach productive age, a variation of these parameters takes place and mostly it is related to uneven light distribution within the tree canopy. The aim of the study was to evaluate the canopy position’s effect on fruit internal and external quality parameters. This is the first study where all the main fruit quality and maturation parameters were evaluated on the same trees and were related to the light conditions and photosynthetic parameters. Four fruit positions were tested: top of the apple tree, lower inside part of the canopy, and east and west sides of the apple tree. Fruit quality variability was significant for fruit size, blush, colour indices, total sugar content, dry matter concentration, accumulation of secondary metabolites and radical scavenging activity. Fruit position in the canopy did not affect flesh firmness and fruit maturity parameters such as the starch index, Streif index and respiration rate. At the Lithuanian geographical location (55°60′ N), significantly, the highest fruit quality was achieved at the top of the apple tree. The tendency was established that apple fruits from the west side of the canopy have better fruit quality than from the east side and it could be related to better light conditions at the west side of the tree. Inside the canopy, fruits were distinguished only by the higher accumulation of triterpenic compounds and higher content of malic acid. Light is a main factor of fruit quality variation, thus all orchard management practices, including narrow two-dimensional tree canopies and reflecting ground covers which improve light penetration through the tree canopy, should be applied.

The circular economy concept promotes the recycling of agricultural waste. This study was aimed at investigating the effects of cattle horn shavings on apple tree nitrogen nutrition. Ligol apple trees on P 60 rootstock were the object of the study. The experiment was conducted in the experimental orchard of the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry, from 2015 to 2018. Two fertiliser rates were tested: 50 and 100 kg/ha N. Horn shavings (14.1% N) were applied at the end of autumn or at the beginning of vegetation in the spring and in one treatment 100 kg/ha N rate was divided into two equal parts and applied both in autumn and spring. The effects of the horn shavings were compared with the effects of ammonium nitrate (34.4% N) and the unfertilised treatment. The lowest mineral nitrogen content was found in the unfertilised orchard soil and the soil fertilised with horn shavings in the spring at 50 kg/ha N equivalent. In all other cases, the fertilisers increased the soil’s mineral nitrogen content. The lowest leaf nitrogen content was found in apple trees that grew in the unfertilised orchard soil or soil fertilised in the spring with 50 kg/ha N of horn shavings (1.58–2.13%). In other cases, leaf nitrogen content was higher (1.77–2.17%). The apple trees with the lowest leaf nitrogen content produced the smallest average yield (34.5–36.6 t/ha). The highest yield was recorded from fruit trees fertilised with 50 kg/ha N of ammonium nitrate applied in spring or horn shavings applied in autumn (42.4 and 41.4 t/ha, respectively). The influence of horn shavings on the other studied parameters was similar to that of ammonium nitrate. Horn shavings, like nitrogen fertiliser, could facilitate nitrogen nutrition management in apple trees, especially in organic orchards, where the use of synthetic fertilisers is prohibited.

Sea buckthorn (Hippophae rhamnoides L. (HR)) leaf powders are the underutilized, promising resource of valuable compounds. Genotype and processing methods are key factors in the preparation of homogenous, stable, and quantified ingredients. The aim of this study was to evaluate the phenolic, triterpenic, antioxidant profiles, carotenoid and chlorophyll content, and chromatic characteristics of convection-dried and freeze-dried HR leaf powders obtained from ten different female cultivars, namely ‘Avgustinka’, ‘Botaniceskaja Liubitelskaja’, ‘Botaniceskaja’, ‘Hibrid Percika’, ‘Julia’, ‘Nivelena’, ‘Otradnaja’, ‘Podarok Sadu’, ‘Trofimovskaja’, and ‘Vorobjovskaja’. The chromatic characteristics were determined using the CIELAB scale. The phytochemical profiles were determined using HPLC-PDA (high performance liquid chromatography with photodiode array detector) analysis; spectrophotometric assays and antioxidant activities were investigated using ABTS (2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) and FRAP (ferric ion reducing antioxidant power) assays. The sea buckthorn leaf powders had a yellowish-green appearance. The drying mode had a significant impact on the total antioxidant activity, chlorophyll content, and chromatic characteristics of the samples; the freeze-dried samples were superior in antioxidant activity, chlorophyll, carotenoid content, and chromatic profile, compared to convection-dried leaf powder samples. The determined triterpenic and phenolic profiles strongly depend on the cultivar, and the drying technique had no impact on qualitative and quantitative composition. Catechin, epigallocatechin, procyanidin B3, ursolic acid, α-amyrin, and β-sitosterol could be used as quantitative markers in the phenolic and triterpenic profiles. The cultivars ‘Avgustinka’, ‘Nivelena’, and ‘Botaniceskaja’ were superior to other tested cultivars, with the phytochemical composition and antioxidant activity.

Impact of orchard management technologies on apple fruit internal quality was tested in several trials performed at the Institute of Horticulture, Lithuanian Research Center for Agriculture and Forestry during 2010-2019. Studies were focused mainly on the research of bioactive compounds: triterpenes and phenols. Studies included rootstocks, crop load regulation, planting distances, fruit position in the tree crown, geographical locations, regulation of tree vegetative growth by root pruning, trunk incision and prohexadione-calcium. 'Auksis' apple fruits on P 67 rootstock and 'Ligol' on P 61 and P 22 had the highest total phenol content, while the lowest total phenol content of both tested cultivars was recorded on M.9 and P 62 rootstocks. Increasing crop load on the tree led to significant increase of phenols and triterpenes. Higher fruit triterpene concentration was recorded on denser planted trees. Root pruning increased accumulation of phenols, while by the application of prohexadione-calcium the accumulation of phenols decreased significantly. Lower triterpene concentration was recorded when tree growth was controlled by trunk incision. Fruits from the top of the tree accumulated significantly higher amount of phenolic compounds, whereas fruits inside the tree crown were characterized by the highest amount of triterpene compounds. Colder climate during the vegetation and shorter vegetation period resulted in significantly higher accumulation of phenolic and triterpene compounds in apples grown in Estonia comparing to fruits grown in Poland. New scientific results on the impact of modern technologies on the changes of internal fruit quality parameters could increase consumption of apples.

The seedlings of myrobalan (Prunus cerasifera) are the most popular rootstocks for plums in Latvia and give large trees. However, dwarfing rootstocks are essential for establishing high density orchards which give earlier yields and lower production costs. An experiment at the Institute of Horticulture, Latvia University of Agriculture was planted in spring 2015 The performance of the dwarfing plum rootstocks Wangenheim prune, VVA-1, S766, M633 and Weiwa was compared against the industry standard Prunus cerasifera. Onto these rootstocks, scion cultivars ' Victoria', 'Jubileum' and the Latvian new cultivars 'Ance', 'Adelyn', 'Sonora' and 'Lotte' were grafted and assessed in a trial with six replicates. In the trial one-year-old trees were planted, the spacing of trees on P. cerasifera was 5x2.5 m while on dwarfing rootstocks it was 5x1.5 m, with two trees plot(-1). After the first growing years there were no significant differences between trunk cross section areas, among different combinations of cultivars and rootstocks. A high number of suckers was found for all cultivars on the rootstocks P. cerasifera (1.3), M633 (1.6), S766 (1.1) evaluating in scores from 1 to 5. Only few suckers were found for all cultivars on the rootstocks Weiwa (0.3 points) and VVA-1 (0.2 points). Almost no suckers were found for all cultivars on rootstock Wangenheim (0.07 points). The highest amount of perished trees (20.8% trees in average for all cultivars) was found on the rootstock P. cerasifera while the lowest number of perished trees was on the rootstock S766 and Wangenheim prune (16.7%). Rootstocks Weiva and M633 did not show any tree loss. The cultivar 'Victoria' on rootstock S766 and cultivar 'Ance' on Wangenheim prune showed the earliest yield.

The effect of tree growth-control technologies on apple tree vegetative development, productivity and fruit quality was investigated with apple cultivar ‘Rubin’ on dwarf rootstock P 60 at the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry in 2015–2018. Eight treatments were established combining tree trunk incision by chainsaw before flowering, application of prohexadione-calcium in different dose and time, summer pruning in August and root pruning before flowering. Root pruning from both sides of the tree significantly reduced tree trunk diameter, shoot length and pruning weights but at the same time reduced fruit weight. It increased tree productivity and enhanced fruit colouring. Two applications of prohexadione-calcium significantly reduced mean shoot length and increased average fruit weight. Summer pruning had a positive impact on fruit colouring. Trunk incisions enhanced leaf P, K and Fe content. Pro-Ca increased leaf Ca content. Trees root pruned from both sides had one of the lowest contents of all tested minerals. All tree growth-control technologies had a positive impact on tree productivity , fruit quality and bearing stability comparing with control treatment.

The aim of this study was to determine the composition and content of phenolic compounds in extracts of plum fruit. Fruit of 17 plum cultivars were analyzed. Fruit samples were collected in 2019 from fruit trees with “Myrobalan” (P. cerasifera Ehrh.) and “Wangenheim Prune” (P. domestica L.) rootstocks. The following glycosides of the flavonol group were identified: avicularin, isorhamnetin-3-O-rutinoside, isoquercitrin, hyperoside, rutin, and an aglycone quercetin. Compounds of the flavan-3-ol group were identified, such as (+)-catechin, procyanidin C1, and procyanidin A2, along with chlorogenic acid attributed to phenolic acids and a non-phenolic cyclitol–quinic acid. Of all the analytes identified in plum fruit samples, quinic acid predominated, while chlorogenic acid predominated among all the identified phenolic compounds, and rutin predominated in the flavonol group. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) revealed that fruit samples of “Kubanskaya Kometa”, “Zarechnaya Raniaya”, “Duke of Edinburgh”, “Jubileum”, and “Favorita del Sultano” cultivars had different quantitative content of phenolic compounds from that observed in other samples. The highest total amount of phenolic compounds was found in the European plum samples of the “Zarechnaya Rannyaya” cultivar, while the amount of quinic acid was the highest in plum fruit samples of the “Jubileum” cultivar.

Impact of planting distances on apple tree growth, yield parameters and internal fruit quality was evaluated in a 14- to 17-year-old orchard planted on super-dwarf P.22 rootstock. Trial was performed at the Institute of Horticulture Lithuanian Research Centre for Agriculture and Forestry in 2014-2017. 'Auksis' apple trees were planted at the distances 3x1, 3x0.75, 3x0.50, and 3x0.25 m. The strongest growth, the highest number and total length of shoots, the highest amount of flower clusters and yield tree(-1) was recorded at planting distances 3x1 and 3x0.75. The growth and yield tree(-1) of very densely planted apples (3x0.25) was significantly lower, in spite of these trees being the most productive and giving the highest yield area(-1). The average fruit weight, diameter and colour were the best at planting distances 3x1 and 3x0.75. Fruit quality parameters significantly decreased in the super dense orchard. Long-term evaluation of apple trees on super-dwarf P.22 rootstock revealed that planting distance 3x0.75 guarantee annual yields of high quality fruits even in a 14- to 17-year-old intensive orchard. In the case of orchard replacement after 10-12 years the optimal planting distance of apple trees on P.22 rootstock is 3x0.5 in order to get the highest yield in the young age.

A study on the influence of planting distances on the growth, productivity and fruit quality of dwarf apple trees in a 15- to 18-year-old orchard was carried out at the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry. Trees of the apple (Malus x domestica Borkh) cultivar 'Auksis' on rootstock P 60 were planted at distances of 3 x 1.5, 3 x 1.25, 3 x 1.00 m and 3 x 0.75 m. With increasing density of fruit trees, single-tree growth, generative development and yield were significantly reduced. The opposite results were obtained when these parameters were evaluated per unit area. Yield and fruit quality measurements were made at two canopy heights: 0-1.5 and 1.5-2.5 m. In the upper part of the fruit tree canopy, fruit average weight and diameter were higher, while the colour was more intense and less dependent on the planting density of fruit trees. In the lower part of the canopy, fruit quality was inferior and with increasing fruit tree density it further deteriorated. Planting distances had a significant effect on the accumulation of sugar, soluble solids and dry matter content: greater planting distances resulted in increased sugar content from 10.97% to 11.90%, soluble solids - from 12.30% to 13.17% and dry matter content - from 13.80% to 14.80%. Conversely, higher accumulation of phenolic and triterpenic compounds in apple fruits was found with decreasing planting distances. A significant increase of phenolic compounds from 2.91 up to 4.03 mg g(-1) DW (dry weight) was recorded at the upper part of the canopy, while an increase of triterpens from 12.9 up to 16.07 mg g(-1) DW - at the lower part of the canopy. The best productivity and fruit quality of 'Auksis' apple trees on P 60 rootstock at the full bearing stage were obtained, when fruit trees had been spaced at 3 x 1.25 m.

Abstract Twenty plum cultivars on Myrobalan (Prunus cerasifera Ehrh.) seedling rootstock were tested in 2012–2017 at the Institute of Horticulture of the Lithuanian Research Centre for Agriculture and Forestry. Plum trees were spaced at 4.5 × 2.5 m and trained as spindles. Orchard floor management included frequent mowing of grass in the alleyways with herbicide strips along tree rows. ‘Duke of Edinburgh’, ‘Kijevas Vēlā’, ‘Dąbrowicka Prune’, ‘Čačanska Najbolje’, ‘and ‘Štaro Vengrinė’ cultivars were the most vigorous plum trees at the end of 6th year. Their trunk diameter achieved 92–96 mm. ‘Valor’, ‘Queen Victoria’, ‘Herman’, ‘Čačanska Najbolje’, ‘Favorita del Sultano’, ‘Ave’, and ‘Jubileum’ cultivars had the lowest trunk diameter — 72–78 mm. The highest cumulative yield of four fruiting years was recorded for ‘Kometa’ and ‘Violeta’ cultivars, respectively, 43.0 and 46.5 kg/tree. ‘Favorita del Sultano’, ‘Rausvė’, and ‘Kijevas Vēlā’ produced the largest fruits — 52–60 g. The smallest fruit occurred on ‘Dąbrowicka Prune’ and ‘Herman’ cultivars, respectively, 22 and 25 g. ‘Dąbrowicka Prune’ had the highest soluble solids content (SSC) — 19.5%. The least SSC was recorded in ‘Kometa’, ‘Violeta’ and ‘Herman’ fruits — 10.6–11.8%. ‘Renklod Rannij Doneckij’, ‘Čačanska Najbolje’, and ‘Valor’ cultivars had the highest fruit flesh firmness.