Clonal Rootstocks Research Articles

Dwarfism mechanism in Malus clonal rootstocks.

The dwarfing mechanism in apple clonal rootstocks is driven by complex interactions between anatomical, hormonal, genetic, and phenolic factors, offering potential for advanced genetic manipulation to optimize tree size and enhance orchard productivity. The widespread adoption of dwarfing rootstocks is pivotal to modern commercial apple (Malus × domestica Borkh) orchards due to their ability to control tree size, shorten the juvenile period, and enhance reproductive growth and overall productivity. The underlying mechanisms of rootstock-induced dwarfism are multifaceted and involve interactions between phenotypic, anatomical, genetic, and phytohormonal factors. This review consolidates current understanding, highlighting the importance of auxin (IAA), cytokinins (CKs), gibberellins (GAs), and abscisic acid (ABA) in mediating growth suppression through impaired transport and hormone signaling. The phenotypic impacts, including reduced root growth, shorter sylleptic shoots, and higher floral bud densities, are discussed alongside genetic loci such as Dw1, Dw2, and Dw3, and the influence of key genes/TFs like MdWRKY9, RGL, and PIN. Anatomically, dwarf rootstocks exhibit a higher bark-to-wood ratio and restricted hydraulic conductivity, which contribute to reduced scion vigour. Furthermore, the accumulation of phenolic compounds in the graft union of dwarfing rootstocks further modulates the growth inhibition. These insights lay the groundwork for advanced molecular breeding strategies, incorporating gene-editing technologies to improve dwarf rootstock development, providing avenues for enhanced orchard management and apple productivity.

The effectiveness of using various types of stimulating substances for the propagation of clonal rootstocks of pome crops in arid zone conditions

The purpose of the research is to identify the effectiveness of the use of various stimulating substances on the economic and biological parameters of plants of clonal apple rootstocks in the conditions of the arid zone of the Northern Caspian Sea (Astrakhan region). The objects were apple tree clonal rootstocks, scion and rootstock combinations. In the mother plantation of vertical layering, 10 breeding forms of rootstocks selected by various scientific institutions were studied. The control was the M series rootstocks, widely used and adapted in the south of Russia: M-9 for dwarf ones, M-26 for semi-dwarf ones, MM-106 for medium-sized ones. In a vertical mother plantation, there were studied variants for leaf treatments with Etamon Bio and Aminovit (control - treatment with water). Average for 2021–2023 foliar treatments significantly contributed to the high yield of first-grade rootstocks for rootstock forms 87-7-12 – 35.4 %; ‘Ural 8’ – 18.0 %; M-26 – 15.0 %; ‘Ural 5’ – 14.0 %; rootstock ‘Malysh Budagovskogo’ – 20.3 % in the variant with Etamon Bio treatment. In the variant with Aminovit treatment, the most number of first-grade layerings were obtained from the rootstock form 87-7-12 – 36.3 %; ‘Ural 8’ – 19.5 %; ‘Malysh Budagovskogo’ – 23.0 %. Foliar feeding with Etamon Bio and Aminovit had a positive effect on the length of the root system, an increase in the diameter of the trunk and an increase in the height of the rootstocks. In the first field of the nursery, the varieties were grafted onto rootstocks of varying vigor. The drugs for study were root formation stimulants Zircon; Ribav Extra; Kornevin. As a result, in comparison with the control, the survival rate of all rootstocks treated in the Zircon root formation stimulator was 100 %.

The Leafy-Stem-Buried Etiolation Contributed to the High Efficiency of Rootstock Vegetative Propagation in Avocado (Persea americana)

Because of their tolerance to root rot and many abiotic stresses, rootstocks are generally required for commercial avocado production. However, cutting and air-layering, which are popular methods of vegetative propagation for producing large numbers of uniform and genetically identical plants, have been unsuccessful for years. To develop a practical and efficient rooting procedure for selected avocado clonal rootstocks, the present research investigated the effects of various factors on rooting cutting. Shoots were divided into three groups (air layering, direct cutting, and stem-buried etiolation) and treated with different combinations (plant growth regulators, PGRs; soaking time; and culture media), in which orthogonal or randomized-block designs were used. The rooting rate, average root length, average root number, average root dry weight, and rooting quality (Q value) were used as evaluation indicators. The results show that etiolation treatment of the mother shoot is the requisite condition for avocado shoot rooting. In addition, the rooting effect of etiolated cuttings was strongly impacted by PGR type, concentration, and soaking time, whereas no significant differences were detected among the culture media. Among these factors, the roots and the survival rates of etiolated cuttings of two hard-to-root varieties were optimal under the following conditions: indolebutyric acid concentration of 2500 mg/L, dipping duration for 5 s, and perlite:vermiculite culture at 1:1. The rooting rate of ‘Dusa’ was generally greater than that of ‘Duke 7’ and reached 82%.

Features of clonal micropropagation of plum PK SK 1 clonal rootstock

Methodological features of the main clonal micropropagation stages of plum PK SK 1 clonal rootstock (of NCFSCHVW selection) are described. The rootstock is characterized by a high adaptability to soil and climatic conditions of the region. In particular, it exhibits good winter hardiness, resistance to overwatered soils, tolerance to drought, and the capacity to grow on heavy soils. Plum seedlings on this rootstock develop a powerful root system. These advantages render the development and improvement of methods for clonal micropropagation of plum PK SK 1 clonal rootstock highly relevant. The research was carried out in 2019-2022. The period of active shoot growth, i.e., the first and second decade of may, was established to be the most optimal period for introduction of explants into in vitro culture. In this period, regeneration reaches 78.1–93.8 %. Eff ective shoot multiplication proceeds on MS medium with Fe-EDTA or MS medium with Fe-EDDHA and 6-BAP in the amount of 1 mg/L, with the highest number of shoots formed from one explant following the fourth passage (on average, 11.7 and 12.3 shoots per explant). A signifi cant eff ect of the 6-BAP concentration on the number of shoots formed was observed. The combined eff ect of the form of chelated iron and 6-BAP concentration on the number of shoots formed was established only after 3-5 passages on MS medium with Fe-EDDHA. The rooting stage of PK SK 1 rootstock can also be carried out on a hormone-free MS medium with Fe-EDDHA. The rooting effi ciency reaches 57.1–61.8 %. On average, 2.4 roots are formed per shoot with a length from 1.2 to 5.1 cm, with the root quality being high (not cartilaginous and not brittle). For the adaptation stage, rooted shoots with a height of at least 2 cm having two or more roots with a length of at least 2-3 cm are selected. A mixture of the Agrobalt plant nutrient soil, vermiculite, and perlite in a ratio of 3:1:1 can be used as a substrate. Following four weeks of adaptation, the number of adapted plants averaged 87.5 %.

Morphological Evaluation of Pear cvs. Santa Maria, Williams, and Deveci Grafted onto Clonal and Seedling Rootstocks

This research was conducted to determine the effects of quince clonal rootstocks [Quince BA29 (BA29) and Quince A (QA)], pear clonal rootstocks [FOX9, FOX11, OHxF333, OHxF87 and FAROLD40] and European pear seedling rootstocks on the morphological characteristics of 'Santa Maria', 'Williams', and 'Deveci' pear cultivars in Bafra (Samsun) ecological conditions in the research years of 2021 and 2022. Morphological characteristics, such as rootstock diameter (mm), trunk diameter (mm), trunk cross-sectional area (cm2), tree height (cm), crown dimensions (width, length, height and volume), leaf stalk length (cm), leaf stalk thickness (mm), leaf dimensions (width, length, area), annual shoot length (cm), node numbers and internode length (cm) were examined in the study. Results of the study revealed significant variation in the case of research years on most morphological attributes; generally, the values were higher in the research year 2022 than in 2021. It has been determined that the effect of rootstocks on all the morphological characteristics was significant except for leaf stalk thickness. The highest morphological values were obtained from OHxF333, FOX11, and FAROLD40 compared to the other rootstocks, and the lowest values were recorded in FOX9, OHxF87, and seedling rootstocks, respectively. Considering the cultivars' effect on the evaluated morphological traits, the highest leaf characteristics, and internode length in the annual shoots were acquired from the 'Santa Maria' cultivar, but all other attributes were higher in the 'Deveci' cultivar. The ' Williams ' cultivar recorded almost all the lowest morphological values. The highest trunk cross-sectional area was determined in the 'Deveci'/OHxF333 (38.63 cm2) and the lowest in the 'Williams'/FOX9 (4.95 cm2). The longest annual shoots were determined in the 'Deveci'/FOX11 (43.05 cm) and the shortest in the 'Williams'/Seedling (16.11 cm). The highest leaf area was observed from the 'Santa Maria'/BA29 (21.11 cm2) and 'Santa Maria'/FOX11 (20.95 cm2) combinations. According to the results of the research, it was determined that OHxF333 rootstock among the evaluated rootstocks performed morphologically better than the others. FOX9 and OHxF87 pear clone rootstocks showed very poor performance compared to other rootstocks.

Obtaining standard clonal rootstocks of the Maak cherry by green cuttings

The Maak cherry (Cerasus maackii Rupr.) has been studied for use as a scion in nursery production. The culture has such economically valuable features as resistance to diseases and pests, winter hardiness, fast regenerative ability, high rooting capacity of green cuttings. The article deals with the peculiarities of cultivation of the Maak cherry by green cuttings in the conditions of the Chelyabinsk region. The objective of the study was to evaluate the Maak cherry for the rooting ability and the possibility of obtaining a standard clonal scion. It has been found that using green shoots of the Maak cherry, 20, 30 and 40 cm long, the rooting capacity of cherry increases by 2.5; 12.5 and 19.1%, respectively, compared to the control variant (15 cm). The yield of standard rootstocks increases, when using longer cuttings 30–40 cm, when compared to the control (15 cm), or 2.5–3.4 times, respectively. Changes also occurred in the increase in the diameter of the conditional root neck, it increased by 9.3; 28.0 and 50.0% more than the control (3.2 mm). It has been proved by the experiment that at cutting length of green cuttings of the Maak cherry with the length of 40 cm, it is possible to get more than 150 pieces of clonal rootstocks suitable for winter grafting from 1m2 of the protected ground during one vegetation period. In green cuttings of the Maak cherry in a greenhouse equipped with a fogging unit, the length of green cuttings planted for rooting has a significant effect on rooting and yield of the uniform clonal rootstocks. When using 30–40 cm long annual shoots cut during the active growth period, rooting ability of the Maak cherry increased 1.3 times, the diameter of the conditional root neck – 1.5 times, the total yield of the suitable for grafting rootstocks – 3.4 times compared to the control variant (15 cm).

Resistance of apple clonal rootstocks to the fruit bacterial blight pathogen <i>Erwinia amylovora</i>

The review is devoted to resistance of apple clonal rootstocks to bacterial blight of fruit trees considering current data on the biology of its pathogen Erwinia amylovora. The paper provides data on the main known loci of quantitative resistance in Malus species, their genetic markers, and resistance of the main forms of foreign selection. The study collects data on the resistance of Russian clonal rootstocks.

Tree performances of eight rootstocks grafted with ‘Šumadinka’ sour cherry

Aim of study: This study was conducted to determine the suitability of seven clonal and one seedling rootstocks for grafting of sour cherry cv. ‘Šumadinka’ trough early tree growth, precocity, productivity and fruit quality. Aim of study: To evaluate the suitability of seven clonal rootstocks and one seedling rootstocks for grafting the sour cherry cv. ‘Šumadinka’ based on early tree development, precocity, productivity and fruit quality. Area of study: A sour cherry orchard in village Prislonica, Serbia, near Čačak city. Material and methods: The sour cherry cultivar ‘Šumadinka’ was grafted onto Colt, MaxMa 14, Krymsk 6, Adara, Cigančica, Gisela 5, Gisela 6 and Myrobalan rootstocks. Standard and validated procedures were used to measure tree growth, productivity (from 2017 to 2020), leaf area, fruit physical properties and fruit chemical composition (from 2019 to 2020). Main results: Significant differences were observed among rootstocks in leaf and petiole dimensions, leaf area, tree vigour, yield, fruit size, soluble solids content, titratable acidity, sugars and vitamin C contents, ripening and sweetness indexes. Trees grafted on Adara exhibited the highest tree vigour, while those on Gisela 6 produced the largest fruit size. On the other hand, Colt trees generally displayed the highest sugar content and sweetness index. Adara also showed improvements in fruit quality characteristics, whereas the properties associated with Myrobalan received the lowest evaluation scores. Research highlights: Adara rootstock demonstrated good adaptability to heavy and acidic soil conditions in Serbia, even though it was originally selected for cherry cultivation in heavy, waterlogged, and calcareous soils in Spain. This adaptability likely contributed to its higher vigour, yield, yield efficiency and good fruit quality.

Recovery of pear clonal rootstock from viruses using complex in vitro therapy

Recovery of pear clonal rootstock from viruses using complex in vitro therapy

Determination of fruit characteristics, nutrients and biochemical contents of Transvalia (Prunus persica L.) peach cultivar grafted on different clonal rootstocks obtained by selection and hybridization

Rootstocks are frequently used in modern orchard practices due to their special characteristics. They not only eliminate the limiting factors in fruit growing but also have advantages such as increasing productivity, fruit quality, dwarfing, and nutrient yield. In addition, rootstocks have a significant impact on plant development, fruit characteristics, nutrients, and biochemical content. The study was conducted to investigate the effects of different peach rootstocks on fruit quality, nutrient content, and biochemical content. A total of 16 rootstocks of the species P. persica were used as test material. GGF3 rootstock has the highest values in terms of fruit weight (297.33 g), fruit width (83.50 mm), fruit length (77.58 mm), seed weight (9.96 g), seed width (28.16 mm), and seed length (43.47 mm) features. The effect of rootstocks on nutrients (except Cu, K, P, and Fe) in the fruits was statistically significant. The effect of rootstocks on nutrients (except Cr and Na) in the leaves was found to be statistically significant. The effect of rootstocks on both leaf and fruit plant nutrient contents varied. The rootstocks had statistically significant effects on fruit nutrient contents (except Cu, K, P, and Fe) and leaf nutrient contents (except Cr, and Na). It has been found that there is a positive relationship between micro and macronutrients. According to the results of biochemical analysis, statistically significant differences were found in biochemical contents. The highest total phenolic, total flavonoid, and total monomeric anthocyanin contents except for the total antioxidant content of peach fruits were observed in Kl 38 rootstock (137.19 mg kg−1, 25.68 mg kg−1 and 7.48 mg kg−1, respectively). The highest total antioxidant content was detected in NG1 and NGF14 rootstocks (349.46 mg kg−1). According to principal component analysis (PCA), the eigenvalue of 13 PCs was above 1.0 and accounted for 86.08 % of the total variation; this effectively showed the variation among peach rootstocks with respect to the traits analyzed. The data obtained show that rootstock varieties have a significant impact on the traits and that the selection of rootstock varieties has a very important place, especially in economic breeding.

Oxidative stress as markers in identification of aluminum-tolerant peach tree rootstock cultivars and clonal selections

ABSTRACT Peach rootstock and scion cultivars are selected in breeding programs considering resistance to pests and diseases, salt tolerance, drought tolerance, and vigor. However, rootstock tolerance to aluminum (Al), which is markedly present in tropical and subtropical soils of the world, is not considered. Thus, it is essential to define potential markers that can contribute to the selection of Al-resistant or Al-tolerant peach rootstocks. The objective of this study was to identify Al-tolerant peach tree rootstock cultivars and clonal selections using physiological and oxidative stress variables. A completely randomized experimental design was used in a 13 (rootstock cultivars and clonal selections) × 2 (with and without Al) factorial arrangement, with three replications. Nursery peach trees of own-rooted ‘BRS Mandinho’ (without rootstock) and nursery trees of ‘BRS Mandinho’ grafted on different rootstock cultivars and clonal selections were grown in a hydroponic system, consisting of two treatments, with and without 100 mg L -1 of Al. Dry biomass, photosynthetic variables, pigment concentration, hydrogen peroxide content, membrane lipid peroxidation, and activity of the antioxidant enzymes were evaluated. The total dry matter production of the own-rooted ‘BRS Mandinho’ trees and the SS-CHI-09-39 and SS-CHI-09-40 selections is affected by the Al presence, representing a decline of 35.4, 37.2, and 24.4 %, respectively, compared to the treatment with Al. The highest total dry matter production in Al presence was observed for the ‘Sharpe’ rootstock. ‘Capdeboscq’, DB-SEN-09-23, FB-ESM-09-43, JB-ESM-09-13, JAH-MAC-09-77, SAS-SAU-09-71, and VEH-GRA-09-55 rootstock selections are tolerant to Al. The use of physiological and biochemical variables shows potential for the selection of clonal rootstocks tolerant or resistant to Al.

Productivity and Fruit Quality of ‘FalstaffPBR’ Pear Variety Grafted on Different Rootstocks

‘FalstaffPBR’ is a pear variety released by CREA and New Plant in 2012. This study focused on the effects of various clonal rootstocks on the main productive and qualitative traits of ‘FalstaffPBR’ scion. The rootstocks used were ‘EMC’, ‘EMH’, and ‘BA29’ for quince (Cydonia oblonga) and pear ‘Farold 40’ (Pyrus communis). Plants were planted in 2009 with a layout that, depending on the used rootstock, varied between 60 and 120 cm on the row, according to the rootstock standard planting system, and 350 cm between rows. The average yield calculated in the trail field in the 4 years of production (2014–2017) was over 22.7 tons ha−1 on ‘BA29’, 22.8 tons ha−1 on ‘EMH’, 16.3 tons ha−1 on ‘Farold 40’, and 18.4 on ‘EMC’. Fruits of the plants grafted on ‘Farold 40’ always had a medium-to-high size, while fruits produced by the plants grafted onto ‘BA29’ have been larger in size since the first years of production. The plants grafted onto ‘EMH’ produced fruits with the highest percentage of red overcolor. The ‘EMH’ rootstock is optimal for ‘FalstaffPBR’ as it gives the plant an intermediate vigor between ‘BA29’ and ‘EMC’, and a good yield per hectare from the first planting years; the average fruit size is excellent.

A First Omics Data Integration Approach in Hass Avocados to Evaluate Rootstock-Scion Interactions: From Aerial and Root Plant Growth to Fruit Development.

Grafting, the careful selection of rootstocks and scions, has played a crucial role maintaining Chilean avocado fruit quality standards in a scenario in which climate change and drought-related issues have considerably decreased avocado fruit production in the last fifteen years. The historical use of seedling rootstocks in Chile has experienced a recent shift towards clonal rootstocks, driven by the potential to produce more consistent and predictable crops. This research aims to compare Hass avocado plants grafted on Mexicola seedling and Dusa® clonal rootstocks in a soilless and protected system using (i) a differential expression analysis of root and leaf samples and (ii) a fruit transcriptomic and metabolomic integration analysis to improve our understanding of rootstock-scion interaction and its impact on avocado tree performance and fruit quality. The results demonstrated that no significant transcriptomic and metabolomic differences were identified at fruit level in the ready-to-eat (RTE) stage for Hass avocado fruit from both rootstocks. However, Hass avocados grafted on the clonal rootstock showed greater aerial growth and slightly increased fruit size than the seedling rootstock due to the enrichment of cell wall-remodeling genes as revealed in leaves and fruit at harvest stage.

Unraveling the effects of melatonin on drought-stressed pear rootstocks: A comparative analysis of Dargazi and Pyrodwarf

Drought stress is known as one of the major challenges in most fruit-growing areas. This research aimed to investigate the amelioration effect of pre-drought exogenous melatonin application on the physiological and biochemical response of `Dargazi’ seedling and `Pyrodwarf’ clonal pear rootstocks, grown under water stress and controlled greenhouse conditions. Drought stress was applied by withholding irrigation water for 40 days on one-year-old un-grafted seedlings and clonal pear rootstocks. Gas exchange, chlorophyll content, relative water content, lipid peroxidation, and enzyme antioxidant activity were examined. Pre-drought treatment of melatonin significantly increased drought tolerance, successfully recovered the lost growth and considerably improved photosynthetic efficiency. The adverse effect of drought stress was ameliorated by melatonin through the possible osmotic adjustment such as the increase of proline (102 and 92 g/g FW for `Dargazi' and `Pyrodwarf' respectively) and soluble sugars as well as the improvement of the antioxidative defense system through the activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX). The `Dargazi’ seedling rootstock showed better tolerance to drought stress with higher photosynthesis, leaf water content, chlorophyll content, antioxidant enzyme activity, lower lipid peroxidation, and H2O2 generation than the Pyrodwarf clonal rootstock. Also, melatonin ameliorated the negative effect of water stress on photosynthesis and growth parameters through the possible inducing osmotic adjustment and anti-oxidative system under the severe drought stress condition on pear rootstocks. SOD, APX, POD, and CAT activities in Dargazi rootstock were significantly higher than those in control plants by 76.1 %, 34.9 %, 20.93 %, and 124.42 % respectively. Similarly, SOD, APX, POD, and CAT in Pyrodwarf pear rootstock increased in enzyme activities by 56.92 %, 24.37 %, 35.53 %, and 259.52 %, respectively. It is concluded that melatonin application as a pre-drought treatment mitigates the negative effects of drought stress in both rootstocks and the Dargazi rootstock exhibits remarkable resilience to drought stress.

Polymorphism in cherry plum (<i>Prunus cerasifera</i>) and its significance for stone crop breeding

A gene pool of cherry plum (Prunus cerasifera Ehrh.) numbering over 1000 accessions including wild forms and released cultivars of various origins has been gathered at the Krymsk Experiment Breeding Station, a branch of VIR. The study of the morphological diversity of cherry plum, or myrobalan plum, made it possible to clarify its position within the system of the genus Prunus L., and to propose an intraspecific system composed of three subspecies: Prunus cerasifera subsp. cerasifera – the typical cherry plum, P. cerasifera subsp. orientalis (M. Pop.) Erem. et Garcov. – the oriental cherry plum, and P. cerasifera subsp. macrocarpa Erem. et Garcov. – the large-fruited cherry plum with the following several varieties: Armenian (P. cerasifera subsp. macrocarpa var. nairica (Koval.) Erem. et Garkov.), Georgian (var. georgica (Erem.) Erem. et Garcov.), Iranian (subsp. macrocarpa var. iranica (Koval.) Erem. et Garcov), Pontic (subsp. macrocarpa var. pontica (Koval.) Erem. et Garcov.), Tauric (subsp. macrocarpa var. taurica (Kost.) Erem. et Garcov.), and the red-leaved cherry plum (Pissard plum) (subsp. macrocarpa var. pissardii (Carriere) Koehne).The most important role of interspecific hybridization involving the species P. cerasifera is in the origin of a number of Prunus L. species, including domestic plum P. domestica L., Fenzl’s almond P. fenzliana Fritsch, and black apricot P. dasycarpa Ehrh., has been established.The cherry plum gene pool had been found to contain donors of a number of traits of importance for breeding, which were used to create an assortment of Russian plum (Prunus × rossica Erem., hybrid myrobalan plum) cultivars and clonal rootstocks of stone fruit crops. Among them, the Russian plum ‘Globus’, ‘Kubanskaya Kometa’, ‘Gek’, ‘Kolonnovidnaya’, ‘Iyulskaya Roza’, and clonal rootstocks ‘Kuban 86’, ‘VVA 1’, ‘Evrika 99’, ‘Best’, ‘Zarevo’ have been regionally adapted and got a wide distribution.An outstanding general combining ability was demonstrated by cherry plum cvs. ‘Pionerka’, ‘Purpurovaya’, ‘Otlichtnitsa’, ‘Ashtarakskaya 2’ and ‘Tsiteli Drosha’, which were used in breeding a number of cherry plum cultivars at the Krymsk EBS, e.g. cherry plums ‘Neberdzhaevskaya Rannyaya’, ‘Kremen’, Russian plum ‘Kubanskaya Kometa’, ‘Iyulskaya Roza’, ‘Naydena’, ‘Gek’, ‘Podarok Sad-Gigantu’, etc.Most effective was the hybridization of Crimean, Armenian and Georgian cherry plum cultivars with the Chinese plum (Prunus salicina Lindl.) ‘Burbank’, ‘Gigant’, and ‘Skoroplodnaya’. As clonal rootstocks, the hybrids of myrobalan plum with peach (‘Kuban 86’ and ‘Fortuna’ rootstocks), with cherry plum ‘Sapa’ (‘Evrika 99’ and ‘Spiker’ rootstocks), as well as with low micro-cherry (rootstock ‘Best’) and Louiseania ulmifolia (Franch.) Pachom. (rootstock ‘Upriamets’) turned out to be very valuable.

In vitro propagation of stone fruit rootstock cultivar Evrica 99 and its influence on some phytochemical traits of fresh apricot fruit

Background: The cultivation of stone fruits is of primary importance in Armenia. Their fruits contain antioxidants, fiber, potassium, vitamin A, C, E, minerals, etc., which have a beneficial effect on human health and prevent many diseases. The concentration of those components varies depending on ecological factors, cultivar, rootstock, cultural practices, etc. Clonal rootstocks are important for increasing orchard density, tree uniformity, and high yields, and they can also affect fruit quality. In vitro culture is a valuable method for rapid propagation of high-quality, virus free plant material. Objective: The purpose of this study was to develop in vitro production technology for the stone-fruit rootstock cultivar Evrica 99, and to determine if rootstocks affect some fresh fruit traits of ´Yerevani´ and ´Sateni´ apricot cultivars. Methods: The shoot apical meristem and lateral bud served as explants for shoot regeneration. Different sterilizing agents at various periods of exposure were used for the explant surface sterilization. Various concentrations of phytohormones, both individually and in combinations, were employed for in vitro regeneration and rooting of plants. The titratable acidity (TA), dry matter (DM), vitamin C, mineral content, total carotenoids (TC), and sugar contents were evaluated in fresh fruit. Results: The most optimal option for explant surface sterilization was the gradual application of calcium hypochlorite [Ca (ClO)2] (2.0% solution, exposure time 10 min) and ethanol (70% solution, exposure time 20 s), as a result of which we had 75.5% survival rate of explants. The efficient medium for in vitro shoot regeneration was MS supplemented with 6-Benzylaminopurine (BAP) 0.8 mg/l, Kinetin (Kin) 0.2 mg/l, and Gibberellic acid (GA3) 1.0 mg/l. The half-strength Murashige and Skoog (MS) medium containing 0.8 mg/l indole-3-butyric acid (IBA) was optimal for in vitro rooting. Rooted plants were successfully adapted with a survival rate of 85.0%. The defined method can be successfully used for 'Evrica 99' cultivar micropropagation. The results obtained showed that fruit quality strongly depended on both the varieties and the rootstock tested. Conclusion: In the current study, an alternative in vitro propagation technology for rootstock cultivar ´ Evrica 99 was developed by direct organogenesis, enabling mass-scale production of virus-free plants that is suitable for commercial purposes as well. The apricot cultivars ´Yerevani´ and ´Sateni´ grafted on the virus-free rootstock cultivar Evrica 99 showed higher fruit quality traits, which are essential for human health and diet. Keywords: ´Evrica 99, fucnctional foods, in vitro regeneration, micropropagation, plant growth regulators, stone fruit rootstock, tissue culture.

Economic and biological indicators of clonal rootstocks of apple trees in conditions of the Astra-khan region

Economic and biological indicators of clonal rootstocks of apple trees in conditions of the Astra-khan region

РЕЗУЛЬТАТИВНОСТЬ НАУЧНЫХ ИССЛЕДОВАНИЙ ПО ОТРАСЛЕВЫМ ПРИОРИТЕТАМ

The article presents the results of the institution’s research work obtained in 2023. Research is focused on solving problems: accelerated creation of new varieties of horticultural crops based on the mobilization of bioresource collections using molecular genetic methods and digital technologies; ensuring environmental and economic sustainability and optimal productivity of perennial agrocenoses, as well as the quality and safety of preserved plant agricultural raw materials based on biologization and digitalization of technological processes. An analysis of the effectiveness of scientific and technical activities is given according to the criteria of research, publishing, publiсation, inventive activity, innovative, educational and financial and economic activities of a scientific institution. As a result of R&D, 115 completed developments of fundamental importance have received, forming the methodological and methodical basis for the creation of scientific and technical products of a priority applied level. Fundamentally new developments in applied research in the fields of knowledge relevant to the scientific institution were 81 developments that provide improvement in the quantitative and qualitative indicators of biocenotic and production processes in fruit and vineyards, technological processes during storage and processing of agricultural products. The gene pool is preserved – 7,253 samples of fruit, berry, nut crops and grapes, replenished with 127 varieties; clones were selected and 7 donors were identified and 53 sources for creating new varieties that combine high potential productivity, winter hardiness, drought resistance, sustainability to the most harmful diseases and pests. The State Register of Breeding Achievements approved for use in 2023 in the North Caucasus (6) region includes 3 varieties of apple trees, one grape variety, one clonal rootstock of small stone fruit crops, a rose variety bred by the scientific institution. Output products are registered in the USAIS electronic accounting database in the form of intellectual property for 99 completed developments. Regulatory documentation has been developed in the form of organizational standards, technological instructions and technical conditions for 37 completed developments.

Cultivation and Study of Varieties, Forms of Pears and Quinces in Conditions of Artificial Fog

In this article, studies of green cuttings of varieties and clonal rootstocks of pear and quince were carried out using artificial fog. Experiments to study the rootability of green cuttings of pear varieties – Hera, Severyanka krasnoschekaya, Extravaganza, Autumn Yakovleva, Tenderness, Allegro, Yakovlev’s Favorite, Skorospelka from Michurinsk, clone rootstocks of pear PG 12 (k), PG 2, PG 17-16 and Northern quince, VA 29, No. 21, Provencal were carried out in a greenhouse with a fi lm a coating equipped with a fog-forming installation. In the future, the following were grown and studied: the number of rooted rootstocks; the average length of the increments; the diameter of the conditional root neck; the average number of roots; the length of the roots. As a result, clonal rootstocks of pears PG 12 (k), PG 2, PG 17-16, Northern quince were isolated, which had the highest rootability over 60.0%.

Seasonal trends in leaf and fruit nutrient concentrations of apple (Malus x domestica Borkh.) grafted on different clonal rootstocks and their effect on fruit quality

Effective nutrient management necessitates monitoring of nutrient requirement, extent and timing of nutrient supply during the fruit development. To achieve a good nutrient balance and its impact on fruit quality, study of nutrient dynamics is of utmost importance as it provides an intriguing stratagem to control tree nutrient status. The research aimed at investigating seasonal patterns of nutrient concentrations in leaves and fruits of apple (Malus × domestica Borkh.) cv Silver Spur on various clonal rootstocks (MM106, M4 and M9) during the year 2019–2020 and their impact on fruit quality. For this purpose collection of leaf and fruit samples commenced from one month after full bloom (May 15) until harvesting (September 18) at an interval of twenty one days and samples were evaluated for both macro and micro-nutrients {Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg) and Boron (B)} and quality characteristics. In general, concentration of N, P, K and B declined continuously in both leaf and fruit toward the end of fruit maturation, whereas leaf Ca and Mg augmented along the cycle, however fruit Ca and Mg increased up to first fruit development stage and then decreased again signifying nutrient dilution along growing season and its effect on fruit quality. With respect to rootstocks, semi-vigorous rootstock MM106 recorded higher values for leaf and fruit nutrient concentrations as compared to dwarf M9 and semi-dwarf M4 rootstocks specifying a significant effect of rootstocks on nutrient absorption.