Clonal Apple Rootstocks Research Articles

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 %.

Establishing surface disinfection protocol for micropropagation of clonal apple rootstock MM111

Establishing surface disinfection protocol for micropropagation of clonal apple rootstock MM111

Establishing surface sterilization protocol for clonal apple rootstock MM106

Surface sterilization is crucial in preparing viable and uncontaminated explants for tissue culture. Utilizing the right sterilizing agent in this procedure can efficiently eliminate the majority of surface contaminants. The present study aimed to establish the best sterilization procedure for clonal apple rootstock MM106 using shoot tips and nodal segments. Two important sterilizing agents, mercuric chloride (ranging from 0.05% to 0.3%) for various durations (2 to 6 minutes) and sodium hypochlorite (ranging from 3.0% to 12%) for different durations (10 to 30 minutes), were employed. The results indicated that the maximum aseptic conditions (80.00% and 80.67%) and survival rates of the cultures (60.66% and 67.33%) for shoot tips and nodal segments, respectively, were achieved through surface sterilization with 0.1% mercuric chloride for 4 minutes, specifically during April, in comparison to March and May of 2021 due to low phenol content and high meristematic activity. The results yielded valuable insights for efficiently propagating clonal apple rootstocks on a local scale, and they have the potential to offer guidance for establishing commercial facilities dedicated to producing these specific clonal apple rootstocks and varieties.

Long-term cold storage of clonal apple rootstocks on growth media with added jasmonic acid: effect and their subsequent development <I>in vitro</I>

The article examines the effect of jasmonic a cid used at concentrations of 0.1-1.0 mg/L in the longterm continuous in vitro cold storage of clonal apple rootstock explants (54-118, 57-490, 57-545, and MM 106) on their subsequent development on under standard cultivation conditions. A positive effect of jasmonic acid was noted on the preservation of the viable explants of clonal apple rootstocks at all used concentrations over a period of 48-54 months (+3-6 ℃) of continuous cold storage, as compared to the explants cultivated without its application. Different concentrations of jasmonic acid in the cold storage medium were found to have no significant effect on the net reproduction of explants that were subsequently cultivated without jasmonic acid under standard cultivation conditions (+20-22 ℃). However, a significant increase in the length of microshoots (by 1.4-1.6 times) and the average number of leaves per microshoot (by 1.2-1.6 times) was observed in all studied forms of clonal apple rootstocks on growth medium with a jasmonic acid concentration of 1.0 mg/L. Subsequently, these explants exhibited no delay in vegetative development in vitro as compared to the explants that did not undergo cold storage (control). Jasmonic acid addition to the growth medium for long-term continuous cold storage at can be recommended as a way to improve the preservation of explants when clonal apple rootstock collections are stored for long periods of time in in vitro culture.

Assessment of low-growing forms of apple clonal rootstocks in the conditions of the Orenburg region

In Russia, as in other countries, breeding work is being carried out to remove the weakest clonal apple rootstocks that are most resistant to adverse environmental factors. The study of the forms of clonal rootstocks of apple trees in irrigated conditions was carried out in 2021-2022 on the basis of the Orenburg branch of the Federal State Budgetary Research Center for Horticulture. The objects of research were the forms of clonal rootstocks of apple trees: OB 2-15, OB 2-24, OB 4-3, OB 2-14, OB 3-14, OB 3-11, OB 2-2, Volga 8, Volga 3, K-1, K-2, ARM-18, 76-23-2, 54 118, 58238, 64-143, Ural 1, Ural 3, Ural 5 No. 8, Ural 5 No. 10, Ural 11, Ural 11 KR. According to the results of the research, the forms of low-growing clonal rootstocks of apple trees OB 2-14, OB 3-14, OB 3-11 were distinguished, characterized by the following indicators: the yield of cuttings from the bush and the unit area (ha) of 2.7 pcs. and 48.1 thousand pcs./ha, 4.2 pcs. and 50.3 thousand pcs./ha, 3.9 pcs. and 50.6 thousand pcs./ha, respectively, with rooting up to 4.5 points. These forms have shown high adaptive capabilities in the extreme conditions of the steppe zone of the Orenburg region and are the starting material for laying intensive plantings.

An Improved Protocol for Rapid in Vitro Multiplication of Clonal Apple Rootstock MM106

An Improved Protocol for Rapid in Vitro Multiplication of Clonal Apple Rootstock MM106

The influence of mineral fertilizers and plant growth regulators on the development of clone rootstocks of apple trees 54-118 in container growing technology

When replicating apple tree planting material in protected soil, technologies for growing plants in container culture using an organomineral substrate, long-acting mineral fertilizers and plant growth regulators are widely used. The purpose of the research was to establish the effectiveness of the combined use of plant growth regulators and long-acting fertilizers when growing clonal apple rootstocks 54-118 in container technology in protected ground. The experiments were carried out in 2021-2023 according to generally accepted methods. The article presents the results of a study of the effect of joint use of OsmocotePRO long-acting fertilizer for 3-4 months. (17-11-10+2MgO+TE) and plant growth regulators indolyl-3-butyric acid (IBA) and gibberellic acid (GA3) on plant growth and development. These technology elements can be used both when obtaining planting material for planting mother plants of clonal rootstocks, and for obtaining seedlings.

Taxonomic structure of tissue endophytic bacterial microbiome in clonal apple rootstock grown on sod-podzolic soils with variant properties

The taxonomic structure of tissue endophytic bacterial microbiome was comparatively studied in microplants (undifferentiated explant callus tissues, passage 25) and 5-year clonal apple rootstocks 57-490 and 54-118 cultured from corresponding tissues (passage 1) on sod-podzolic soils with variant granulometry, chemical, physical and physicochemical properties. Proteobacteria (91.6 %) predominated in vitro tissues among other endophytic bacterial phyla in rootstock 57-490, while Proteobacteria (52.5 %) and Firmicutes (47.4 %) — in rootstock 54-118. The endophytic Firmicutes ratio vs. in vitro tissues decreases (0.7-2.0 %) in roots and more severely (0-0.2 %) in leaves. Endophytic Actinobacteriota are revealed in 11.7 % in roots of the study rootstock in heavy loam soil, whilst in medium loam their ratio drops to 2.74.1 % in roots and 0.1-0.2 % in leaves. The phylogenetic diversity indices estimation for main endophytic bacterial phyla in apple rootstock tissue recovers their essentially lower diversity and evenness in culture endosphere (Shannon index 0.42-1.00) vs. open soil roots (1.34-2.08). The leaves Shannon index is typically low (0.06-0.13) indicating poor diversity and evenness of the main endophytic bacterial phyla.

Experimental analysis of leaf drought resistance at the collection of clonal apple rootstocks bred by the Michurinsk State Agrarian University

Experimental analysis of leaf drought resistance at the collection of clonal apple rootstocks bred by the Michurinsk State Agrarian University

Identification of dwarfism loci Dw1 and Dw2 in clonal apple rootstocks using molecular markers

The paper presents the results of identification of quantitative trait loci (QTL) of Dw1 and Dw2 involved in the control of dwarf growth in clonal apple rootstocks using the molecular markers. In total, 14 forms of rootstocks were analyzed. The microsatellite markers Hi01c04, Hi04a08, CH03a09 (for the Dw1 locus), MDP0000365711, and MDP0000243703 (for the Dw2 locus) were used in the study. Analysis of the results did not reveal a relationship between the presence of a marker and the manifestation of a sign. Of the three markers of the Dw1 locus, only Hi01c04 amplifies a fragment of the expected size of 120 bp. It was found in 9 forms of rootstocks (PB-4, 57-491, 83-1-15, M9, G16, 2-12-10, 2-9-102, 4-6-5 and 70-20-20). The Hi01c04 marker was identified in both dwarf and medium-sized forms. Of the two markers of the Dw2 locus, the desired fragment is amplified in MDP0000365711. It is typical for almost all genotypes. The exception is 83-1-15, 2-12-10 and 70-20-20, which have a null allele. To assess the genetic diversity of the Dw1 and Dw2 loci, 6 microsatellite sequences Hi01c04, Hi04a08, CH03a09, CH02d08, MDP0000365711, and MDP0000243703 were used. In 14 studied samples, 29 allelic variants ranging in size from 102 bp. up to 170 bp were identified. The number of alleles per locus varied from 1 (for the MDP0000365711 locus) to 7 (for the Hi04a08 locus). No rare alleles were identified. All alleles were observed more than three times. Based on the analysis of SSR spectra, a dendrogram reflecting the similarity of the genotypes under study was built.

Digitalization of the breeding process of clonal apple rootstocks

The paper shows the results of many years of experience in breeding low-growing clonal apple rootstocks at Michurinsky State Agrarian University. The relevance of the introduction of digital technologies at all stages of the breeding process from the formation of a data bank for the selection of parental pairs to research in the garden of the competitive study of rootstock-varietal combinations is shown. The apparatus and software for specific research stages are proposed. It is found that the developed methodology and digital technologies make it possible to significantly reduce the time of the breeding process, achieve the intended results faster and more efficiently and most fully reveal the genetic potential of breeding achievements.

The analysis of the suitability of using waste from the production of planting material for apple trees to obtain natural anthocyanin dyes

The analysis of the content of pigments in the stems of clonal apple rootstocks bred by Michurinsky State Agrarian University showed a high content of anthocyanins (more than 200 mg/100 g for rootstock 54-118). When determining the qualitative composition, it was revealed that anthocyanins in the stems of the rootstocks are represented by three groups, while there are differences in the shape of the rootstocks. As a source of pigment production, it is necessary to select rootstocks with a high endogenous synthesis of anthocyanins (i.e. red-leaved forms 54-118, 57-491, 98-7-77, etc.), during the cultivation of which, in addition to the main product—detachable rooted cuttings-one can additionally receive from 3 to 10 kg of anthocyanin dyes from 1 hectare of mother plant.

НАИБОЛЕЕ РАСПРОСТРАНЁННЫЕ ОРГАНИЗМЫ-БИОИНДИКАТОРЫ ПЛОДОРОДИЯ ПОЧВ СЕВЕРА

The research was conducted in the Tambov and Lipetsk regions. A comparative assessment of the sensitivity of the most common and publicly available bioindicators of soils in the northern part of the Central Chernozem region was carried out. Among cereals and leguminous crops, simply and alfalfa are very sensitive to changing the acidity of the soil. From cruciferous vegetable plants, lettuce and radish react well to the formation of humus-rich soils and the change of soil type in the rosette phase during the growth of the root crop (the biochemical composition of the root crop changes). Leaf lettuce and spinach react sensitively not only to the type of nitrogen ferti-lizer, the presence of chlorine, but also to the dose of nitrogen for the active substance. The cu-cumber reacts sensitively to different levels of easily hydrolyzed nitrogen in the soil by the time the first whiskers are formed. Winter cereals (wheat and triticale) are good bioindicators for dif-ferent soil bonuses and their biomass shows a different attitude to the soil from two zones of apple orchards – row spacing and trunk strips. Barley is also responsive to soil bonitet. All its above-ground organs change the content of the common forms of nitrogen, phosphorus and potassium when the soil conditions change, and only in the ear of these elements of nutrition remain in the optimal range. Apple seedlings with their aboveground biomass, the number of leaves and their water regime react to changes in the properties of the humus horizon, soil fatigue and the change of the soil horizons themselves. In response to an increase in the content of humus, potassium, and manganese in the soil and a change in pHKCl in the leaves of clonal apple rootstocks PB-9 and 62-396, the amount of potassium, phosphorus, calcium, and magnesium changes. Rootstock 62-396 sensitively changes the content of anthocyanins, chlorophyll and carotenoids in the leaves in re-sponse to the change in soil type. Yeast and mold fungi reduce their number when the pesticide load on the soil increases. The complex of cellulose-decomposing soil microorganisms reacts sen-sitively to the change of the soil horizon, soil type and anthropogenic transformation during the development of land for apple orchards.

Assessment of fire blight resistance in apple clonal rootstocks using molecular markers

Background. Clonal apple rootstocks are one of the main components of intensive gardening. The degree of rootstock damage by fire blight affects the resistance of the variety–rootstock combination. The paper presents a study on marking quantitative trait loci (QTL) of resistance to fire blight Erwinia amylovora in clonal apple rootstock.Materials and methods. A collection of 20 rootstock forms was analyzed. For the study, SCAR markers GE-8019, AE10-375 and microsatellite marker CH-F7-FB1 were used.Results. Polymorphism was observed for all three markers, and their various combinations in one genotype were revealed. It was previously noted that genotypes that carry all three markers were more resistant than those that lack them. The presence of all three markers was observed only in forms 62-396 (В10), 16-1 and 2-9-102. The other genotypes did not have the GE8019 marker. The AE10-375 marker was identified in eight clonal rootstocks. Microsatellite marker CH-F7-FB1 was present in all tested rootstocks. However, polymorphism was detected there. Most genotypes had a 174 bp fragment, but a 210 bp fragment was identified in two of the 20 forms. Clonal rootstock 70-20-21 proved heterozygous for this marker. The analyzed collection also included samples that had only the microsatellite marker: G16, Malysh Budagovskogo, Paradizka Budagovskogo (B9), 54-118 (В118), 57-491, 70-20-20 (В119), 70-20-21, 71-7-22, 76-3-6, 83-1-15, 87-7-12, and 2-12-10. The study of rootstock forms on the basis of resistance to metabolites of the fire blight pathogen was carried out under laboratory conditions using the E. amylovora culture filtrate in vitro on leaf explants. Most of the studied genotypes had different combinations of markers. However, the experiments showed that forms 62-396 and 14-1 with two out of three markers (AE10-375 and CH-F7-FB1) phenotypically manifested the trait of resistance to metabolites of E. amylovora.

Phylogenetic diversity of the endophytic bacterial component of the microbiome of apple clonal rootstocks during in vitro reproduction and cultivation under various agroecological conditions

The phylogenetic diversity of the endophytic bacterial component of the clonal apple rootstock microbiome 57-490 and 54-118 was studied for microplants and 5-year-old plants grown from the same tissue culture and growing on sod-podzolic soils of different granulometric composition with different chemical, physicochemical and physical properties. Proteobacteria (91.6%) in rootstock 57-490, Proteobacteria (52.5%) and Firmicutes (47.4%) in rootstock 54-118 are the predominant phylum of endophytic bacteria in apple rootstock plant tissues in vitro culture. The relative amount of phylum Firmicutes endophytic bacteria, in comparison with in vitro culture, decreases in the roots to 0.7-2.0%, and even more significantly in the leaves (to 0-0.2%). At cultivation on heavy loamy soil, endophytic bacteria belonging to the phylum Actinobacteriota (11.7%) are found in the studied rootstock roots, the relative content of which, when grown on medium loamy soil, in the roots decreases to 2.7-4.1%, in the leaves – to 0,1-0.2%. The data show that in the endosphere of the culture in vitro, the diversity and uniformity of the community of endophytic bacteria is significantly lower (Shannon index 0.42-1.00) than in the roots of rootstocks grown in the outdoor growing (1.34-2.08). For leaves, the Shannon index is characterized by the lowest values (0.06-0.13).

Rhizogenesis in clonal apple rootstocks (Malus Mill.) in vitro depending on the influence of abiotic factors

In vitro culture at the rooting stage the aft ereff ect of the use of earlier (during proliferation) growth regulators with cytokinin activity (6-benzylaminopurine and thidiazuron) and the eff ect of lamps of diff erent spectral composition on the percentage of rooting and biometric parameters of the development of the roots of clonal apple rootstocks were studied. The following forms of apple clonal rootstocks were taken as objects of research: 54-118, 57-490, 57-545, ММ 106 and М 26. The research methods used at the stages of in vitro culture studies corresponded to those generally accepted for this section of research. Studies were performed on two variants of explants, one part was cultured at the proliferation stage on media with 6-benzylaminopurine and the other on media with tidiazurone. It was found that explants that were cultivated at the stage of proliferation on media with thidiazuron had a tendency to a subsequent increase in the number of roots (at the stage of rooting) by one microscopic cut, in comparison with cultivation on media with 6-benzylaminopurine, by 1.1-1.3 times, and this regularity was observed in all studied clonal rootstocks of the apple tree. It was noted that when explants were illuminated, explants had a greater percentage of rooting when illuminated with phytolamps in comparison with lighting with lamps with a color temperature of 6500K by 1.1-1.4 times in all studied apple rootstocks, and an increase in the number of roots per one microstalk was observed (for excluding rootstock 57-490), by 1.1-1.9 times. During the research, the specificity of rooting of clonal apple rootstocks was observed under the infl uence of the composition of light and the use of 6-benzylaminopurine and thidiazuron at the stage of proliferation, which was expressed in a higher ability to rhizogenesis of some rootstocks compared to others. The rootstocks MM 106 (83.3-93.9 %) and M26 (87.8-92.7 %) had a greater percentage of rooting, according to the average number of roots per one microcut, rootstocks 57-545 (15.4 pcs.), MM 106 (11.2 pcs.), and M 26 along the average root length (27.0 mm).

Изучение клоновых подвоев яблони в маточнике и питомнике в Предгорной зоне Крыма

Цель исследований - изучение влияния подвоя, сорто-подвойных сочетаний на выход и качество саженцев яблони. Объектами изучения являются сорта яблони Таврия и Аврора Крымская на клоновых подвоях: К 105, К 108, К 109, К 110, К 120 и К 121 крымской селекции в сравнении с EM-IX и ММ-106 - контроль. Исследования проводились в Предгорной зоне Крыма на базе отделения «Крымская опытная станция садоводства» ФГБУН «НБС-ННЦ». Почвы опытных участков - чернозём южный карбонатный. Обеспеченность подвижными формами азота (1,5-1,9 мг) и фосфора (2,8-6,5 мг на 100 г абсолютно сухой почвы) - средняя, обменным калием (44-58 мг) - высокая. Учёты и наблюдения вели по методикам полевых опытов с плодовыми культурами. Известно, что рост деревьев, их скороплодность и продуктивность плодовых насаждений во многом зависит как от подвоя, сорта, так и от качества посадочного материала. Отмечено, что не все типы подвоев, обладающие высокими показателями в маточнике, отвечают аналогичным требованиям в питомнике и, наоборот. В связи с этим возникает необходимость в изучении подвоев в питомнике в сочетании с перспективными сортами в конкретных почвенно-климатических условиях. Анализ полученных данных показывает, что самым высоким общим выходом отводков, в среднем за годы исследований, характеризуются подвои К 120 (362 тыс.шт./га), К 121 (299,8 тыс.шт./га). Проведенные исследования в маточнике и питомнике подтверждают предположение о перспективности новых клоновых подвоев, которые адаптированы к атмосферным стресс-факторам и устойчивы к высокому содержанию карбоната кальция в почве (К 120, К 121) и отдельным болезням (мучнистой росе). Подвой К 109 по комплексу хозяйственно-биологических свойств превосходит районированные. The purpose of research is to study the influence of rootstock, variety-rootstock combinations on the yield and quality of apple-tree seedlings. Objects of the study are the apple varieties ‘Tavria’ and ‘Aurora Krymskaya’ on clonal rootstocks: K 105, K 108, K 109, K 110, K 120 and K 121 of Crimean selection in comparison with EM - IX and MM - 106 as a control. The studies were carried out in the Piedmont zone of Crimea based on the Crimean Experimental Horticultural Station branch of the FSBSI NBG-NSC. Soils of experimental plots are southern carbonated black soils. The provision with active forms of nitrogen (1.5 - 1.9 mg) and phosphorus (2.8 - 6.5 mg per 100 g of absolutely dry soil) is average, with exchangeable potassium (44 - 58 mg) is high. Records and observations were carried out according to the methods of field experiments with fruit crops. It is known that the growth of trees and their early maturity, cropping capacity of fruit plantations largely depend on both the rootstock, the variety, and the quality of planting material. It is noted that not all types of rootstocks with high rates in stock nursery meet similar requirements in nursery garden and vice versa. In this regard, it is necessary to study rootstocks in the nursery in the combination with promising varieties in specific soil and climatic conditions. Analysis of the data obtained shows that the highest total yield of layers, on average over the years of research period, is a characteristic of rootstocks K 120 (362 thousand pieces/ha), K 121 (299.8 thousand pieces/ha). The studies carried out in the stock nursery and nursery garden confirm the prospective viability of new clonal rootstocks, adapted to stress factors of atmosphere and resistant to a high content of calcium carbonate in the soil (K 120, K 121) and certain diseases (powdery mildew). The rootstock K 109 in terms of the complex of economic and biological properties is superior to the area-specific.

Modified elements of the technology of in vitro propagation of horticultural crops

The optimized technology for in vitro propagation of such horticultural crops as apple and pear clonal rootstocks, raspberry and black currant varieties is based on modification of culture factors and on realization of morphogenetic potential of the studied genotypes. It was found, that regeneration ability in vitro is determined not only by chemical factors of culturing, but as well as by genotypical peculiarities of plants. The paper regards the advanced technology peculiarities for clonal apple rootstock propagation where the application of water-soluble substances as mineral base allows to simplify the process of preparing the nutrient media. The number of micro-shoots with their length of more than 1.5 cm will be increased by 13.4-43.6 %, the root formation process will be accelerated by 1-2 weeks. Micro-shoot and the root system quality will be improved. The rooting ability occurred to be accelerated by 20.0-93.3 % and adaptability of ex vitro plants increased by 4.7-33.3 % and the yield of the regenerated plants over 6 passages by 1.1-27.0. All these measures allowed us to reduce labor costs by 16.7 % and Mo cost price by 52.01 roubles. The optimized technique for clonal micropropagation of promising raspberry varieties is based on rooting of microshoots directly in soil substrate, excluding the in vitro stage of rooting. The elimination of the rhizogenesis stage from in vitro cycle allows reducing the number of subcultures by one passage. The technique above allows us to reduce labor costs for production of Mo by 27.9 % and the cost of adapted ex vitro plant by 44.6 roubles. The improved technique for clonal micropropagation of promising black currant varieties allows us to better the micro-shoot quality and to increase the number of micro-shoots suitable for rooting by 6.2- 86,5 % depending ok genotype and use hormon free nutrient medium for root formation.

Development of methods for introducing hybrid progeny of Malus sieboldii Rehd. at in vitro conditions

The paper provides data on the use of the Malus sieboldii Rehd. as a genetic donor of economically valuable traits in breeding low-vigorous clonal apple rootstocks. The method of embryo culture is proposed as a way to increase the efficiency of distant crosses. The studies were carried out using seeds obtained in three combinations of crossing (M. sieboldii x Malysh Budagovskogo, M. sieboldii x 60-160, M. sieboldii x 76-3-6). As sterilizing agents when introduced into culture in vitro, we used industrial disinfectant «Belizna (Whiteness)», the sanitizer «Ecocid C» + «Belizna» and the sanitizer «BioPag C» + «Belizna». It was found that additional pretreatment with «Ecocid C» (1.0%) and "BioPag C" (0.4%) for 50 minutes before using the disinfectant «Belizna» contributes to the production of sterile explants up to 61.5% compared to the control. The best results were obtained when combine using «Ecocid C» (1.0%, 50 min.) and «Belizna» (50%, 5 min.). After 28 days, due to the low number of developing embryos, the method of dissection of a part of the cotyledons of hybrid seeds was used. As a result, up to 65.3% of hybrid plants were obtained, compared to 4.2% of the control.

Patterns of development of advanced clonal apple rootstocks of the Michurinsk State Agrarian University selection in the mother plantation

This paper reveals main patterns of development of advanced clonal apple rootstocks of the Michurinsk State Agrarian University selection in the mother plantation. The studied growth and development indicators of shoots, as well as the level of their rooting in 40 genotypes, demonstrate significant heterogeneity of hybrid plants, which is due to their different genetic origin and the associated unequal growth force of parent shrubs. Correlations between the main quantitative morphological characters of parent shrubs of the studied genotypes were revealed. An interrelation of the height of the parent shrub and the area of its leaf surface is noted - on the expectation of 0.71 shoot; for the entire uterine shrub – of 0.45; between the output of standard layering from the shrub and the average rooting score (at 0.72). Promising clonal rootstocks with high yield indices in the mother plantation have been identified.