Selection of seed and vegetative rootstocks for fruit crops

Numerous and diverse in terms of environmental conditions, the fruit-growing zones of the country and the wide range of fruit crops zoned in accordance with this define the variety of seed and vegetatively propagated rootstocks.

Seed rootstocks are used for growing grafted nursery plants of pome fruits and stone fruits. In the regions where they are used, they are sufficiently resistant to adverse environmental conditions, form a powerful, deeply penetrating root system, and are durable. However, seed rootstocks are characterized by genetic heterogeneity. Trees grafted onto them are vigorous and late-maturing.

For seed production, rootstock-seed orchards are established from selected superior semi-cultivated forms or cultivars. It is promising to establish rootstock-seed orchards on a breeding basis by selecting parental forms in order to utilize heterosis for obtaining rootstocks of a certain quality.

Vegetatively propagated clonal rootstocks are less common, but they are of great importance in the intensification of fruit growing, especially in the southern fruit-growing zone, where they are widely used in pome fruit orchards. Clonal rootstocks of stone fruits are currently being tested and introduced into production in our country. Vegetative propagation ensures genetic homogeneity of the rootstocks within each form and uniformity of development of the aerial part of grafted trees.

The variety of existing and newly created types of vegetatively propagated rootstocks with various hereditary properties allows for effective management of growth vigor, precocity, productivity, and longevity of grafted trees within a wide range. The disadvantages of vegetatively propagated rootstocks, particularly for apple and pear, are as follows:

• reduced frost resistance of the roots, which limits their distribution;
• insufficiently deep root penetration;
• insecure anchorage in the soil, which determines the conditions of nutrition and irrigation, the level of agrotechnology, etc.

The noted disadvantages of clonal rootstocks are taken into account when choosing a site and soil for an orchard, as well as when developing and implementing a complex of agrotechnical measures aimed at more fully meeting the requirements and utilizing the high potential productivity of the cultivated cultivar-rootstock combinations with minimal labor and resource costs.

In accordance with the environmental conditions of the zone, the type of plantings, and the cultivation technology applied, the following can be used as rootstocks for apple trees:

• seedlings of domestic apple cultivars or wild forms;
• dwarf vegetatively propagated (clonal) rootstocks;
• semi-dwarf vegetatively propagated (clonal) rootstocks;
• medium-growing vegetatively propagated (clonal) rootstocks.

The domestic (cultivated) apple tree is the most common vigorous seed rootstock in the Krasnodar Territory. It is highly compatible with zoned cultivars, ensures vigorous growth, productivity, and environmental stability of the trees. After many years of testing, seedlings of the following cultivars are used in the territory: Anis Kubanskiy, Borovinka, Grushovka Revelskaya, Stolbovka, and others.

The European wild apple is used as a seed rootstock in the Central fruit-growing zone of the Russian Federation, in Belarus, in Ukraine, and in the steppe regions of the North Caucasus. It is highly compatible with most cultivars but is not sufficiently winter-hardy in severe, snowless winters.

The Oriental (Caucasian) apple tree is a vigorous rootstock that grows in the forests of the Caucasus. Its frost and drought resistance are satisfactory. The rootstock is not sufficiently compatible with some apple cultivars; only the Melba, Anis Kubanskiy, and Renet Simirenko cultivars are permitted to be grafted onto it.

The cherry crabapple (kitayka) is distinguished by high frost resistance and is used as a seed rootstock in zones with severe winters. However, this rootstock has insufficient compatibility with many cultivars.

The Sievers apple tree is a vigorous, drought-tolerant seed rootstock with increased salt tolerance, growing in forests. It is zoned in Central Asia.

The Siberian crabapple and renet-type apples are highly winter-hardy rootstocks, zoned: the first in Siberia and the Far East, the second in the Urals and regions of Siberia with snowy winters.

Clonal (vegetatively propagated) apple rootstocks predominate in the orchards of the southern fruit-growing zone. The most successful classification of clonal apple rootstocks is the one proposed in 1912 by Hatton at the East Malling Research Station (England). Subsequently, it received worldwide recognition.

The collected collection of rootstocks from different countries was divided after study into 16 types based on the growth habit of the trees grafted onto them. They were assigned the symbols EM1–EMXVI. Later, the number of rootstocks increased to 27.

In the 1920s, the East Malling Research Station, together with the Merton Institute of Horticulture, created cultivars resistant to woolly aphid, which were designated with the symbols MM101–MM115. Later, the Roman numerals and rootstock designations were replaced by Arabic ones, and the EM symbols (capital letters of the research station) were replaced by M (Malus – apple).

The modern classification of apple rootstocks is based on their influence on the growth vigor of the grafted cultivar. In this regard, rootstocks are most often divided into 6 categories:

• very dwarf;
• dwarf;
• semi-dwarf;
• semi-vigorous;
• vigorous;
• very vigorous.

The very dwarf rootstock M27 has not yet been widely adopted in commercial orchards.

Dwarf rootstocks for intensive and super-intensive orchards

The choice of a dwarf rootstock determines planting density, precocity of the trees, and the need for support structures. Modern dwarf rootstocks of domestic breeding allow for efficient use of nutrition area and maximizing yield in the very first years after planting.

Rootstock SK3 (hybrid of Borovinka x M8) is optimal for creating super-intensive plantations with a planting density of up to 1500 trees per hectare. Trees on this rootstock are very low-vigorous — 25–30% smaller than on the classic M9, and require mandatory support. The rootstock provides high precocity, excellent yield and fruit quality, and is compatible with all regionalized cultivars.

Rootstock SK4 (hybrid of M8 x Borovinka) is similar to M9 in terms of vigor, but anchors much better in the soil. It is well-adapted to arid conditions and high summer temperatures. This rootstock is recommended for orchards with a planting density of up to 1000 trees per hectare, as well as for private plots.

Rootstock SK7 (selected from MM106) allows for growing trees without support, as they anchor firmly in the soil and do not produce suckers. The vigor of grafted trees is 10–15% lower than on M9. The rootstock is drought-tolerant, winter-hardy, and suitable for intensive orchards with a planting density of over 1200 trees per hectare.

In the Middle Fruit-Growing Zone, Budagovsky's Paradizka is also used as a relatively winter-hardy dwarf rootstock.

• Yield of SK3 layers in the 5th year of the growing season — up to 10 units per bush
• Yield of standard SK3 nursery plants in the nursery — 90–100%
• Yield of SK4 layers in the stool bed — up to 15 units per bush
• Yield of SK7 layers in the stool bed — up to 13 units per bush

When propagating by horizontal layering, the SK7 rootstock responds excellently to mulching with organic substrates, such as rice husks. In the stool bed, it forms a fibrous root system with elements of skeletal roots.

Rootstock M9 remains the primary dwarf rootstock for the southern zone of horticulture, ensuring the onset of fruiting in the 2nd–3rd year after planting. However, when using it, an agronomist must consider the risks associated with the brittleness of the wood and sensitivity to climatic factors.

Semi-dwarf and semi-vigorous rootstocks: growing season characteristics

For orchards with lower planting density and more challenging soil conditions, semi-dwarf rootstocks are chosen. They provide better anchorage for trees and resistance to adverse environmental factors.

Rootstock M7 is characterized by good rooting of layers and a high yield of standard nursery plants that withstand transplanting well. In the orchard, trees initially grow as semi-vigorous, but with the onset of fruiting, their growth slows down noticeably. The disadvantages of M7 include a tendency to form suckers, poor anchorage in the soil, and some heterogeneity of grafted trees.

When choosing a rootstock for specific soil and climatic conditions, it is necessary to assess the winter hardiness of the root system, the strength of the wood, and the timing of the onset of fruiting. Below are the comparative characteristics of the main clonal rootstocks of apple.

Rootstock	Vigor of the grafted tree	Vegetative propagation	Root frost resistance, °C	Root strength	Onset of fruiting, year
M27	Very dwarf	Good	—	Brittle	2–3rd
M8	Dwarf	Good	–10	Brittle	2–3rd
M9	Dwarf	Average	–10	Brittle	2–3rd
M7	Semi-dwarf	Good	–11	Strong	3–4th
M26	Semi-dwarf	Average	–10	Strong	3–4th
MM102	Semi-dwarf	Good	–10	Strong	4–5th
MM106	Semi-dwarf	Good	–12	Strong	4–5th
M2	Semi-vigorous	Poor	–10	Strong	4–5th
M3	Semi-vigorous	Good	–12	Strong	3–4th
M4	Semi-vigorous	Good	–11	Average	4–5th
MM104	Semi-vigorous	Good	–12	Strong	5–6th
M111	Semi-vigorous	Good	–10	Strong	5–6th
A2	Semi-vigorous	Good	–14	Strong	5–6th

Semi-dwarf rootstocks: balance of precocity and stability

The semi-dwarf rootstock M26 ensures a high yield of quality nursery plants in the nursery, although it produces only an average number of layers in the stool bed. Before the onset of fruiting, trees on M26 grow rapidly, and the first commercial harvest is produced as early as the 3rd–4th year. In terms of requirements for soil and climatic conditions, this rootstock is similar to the popular M9.

• Start of fruiting on M26 — 3rd–4th year after planting
• Critical soil temperature for CK2 roots — from -14 to -16 °C
• Yield of layers per 1 hectare of M3 rootstock mother plantation — 120–150 thousand units

The domestic semi-dwarf rootstock CK2 (1-48-41) exceeds M9 in growth vigor. In the orchard, trees grafted on it are characterized by precocity and high yield. The main value of CK2 is the high frost resistance of the root system, which withstands soil cooling down to -14...-16 °С. Although the wood of CK2 is brittle, the thick main roots securely hold the trees, preventing leaning and uprooting.

The semi-dwarf rootstock MM102 propagates well but is sensitive to soil type and groundwater level. On fertile loams, it behaves as a medium-vigor rootstock, while in sandy soils, it reduces growth vigor to semi-dwarf. Trees on MM102 are firmly anchored in the soil, enter fruiting early, and show high yield. At the same time, the rootstock poorly tolerates high groundwater levels and a shallow soil layer.

The rootstock MM106 behaves as a medium-vigor rootstock on rich chernozems. Its developed fibrous root system easily adapts to waterlogged soil and high groundwater levels. Nursery plants tolerate transplanting well, start fruiting early, and produce high yields. However, despite high frost resistance, this rootstock has poor drought tolerance.

Foreign clonal rootstocks are also promising for creating intensive orchards. Among dwarf forms, Mark9 (USA), Bemali (Sweden), and P16 (Poland) stand out. In the semi-dwarf group, Marioka 3 (Japan), V.2 (Canada), and P14 (Poland) show good results.

Medium-vigor rootstocks: soil requirements and risks of windthrow

The medium-vigor rootstock M2 is demanding regarding water regime and soil type. It develops well on drained sandy loams and loams, performs excellently on chernozems, but is sensitive to waterlogging. On dense soils of humid foothill slopes, its productivity drops sharply. In the mother plantation, M2 roots poorly and often becomes overgrown, but the survival rate of nursery plants in the nursery remains high.

The rootstock M3 on rich soils provokes excessive growth of the aerial part and delays the onset of fruiting. In the mother plantation, it does not become overgrown and provides a high yield of layers; however, in the nursery, the survival rate of budded plants is mediocre due to the short period of sap flow. The powerful but superficial root system of M3 is resistant to high groundwater, waterlogging, and slight soil salinity.

The popular medium-vigor rootstock M4 propagates well and tolerates transplanting excellently. Trees grafted on it are precocious and highly productive in fertile soils but have weak anchorage. Superficial roots poorly hold plants in the first years after planting, leading to trunk leaning and windthrow during heavy rains and winds.

The domestic medium-vigor rootstock CK1 (1-48-46) forms many straight shoots without lateral branching in the mother plantation. In the orchard, trees on CK1 grow moderately — weaker than on M3 and M4, but they exceed them in productivity. Disadvantages of the rootstock include poor drought tolerance and the formation of abundant root suckers in the young orchard, which gradually die off as the canopy closes.

Pear rootstocks. The pear crop is most often grafted onto seed rootstocks derived from local wild, semi-cultivated forms and cultivars.

Common pear (wild pear) is used as a vigorous seed rootstock (local forms) in the main regions of the country. Compatibility with cultivars is good. The rootstock is relatively salt-tolerant. Winter hardiness and drought tolerance are satisfactory.

Caucasian pear is the main seed rootstock for pears in the North Caucasus (except for steppe areas) and Transcaucasia. Stands of this pear are located in the foothill and mountain zones and extend to the Kuban plain. Seedlings of Caucasian pear tolerate transplanting poorly, which reduces the yield of nursery plants. Trees on this rootstock have a powerful, slightly branching root system. They grow well in deep, heavy-loamy, moist soils and tolerate soils with high groundwater levels poorly. Tree growth is very strong. The onset of fruiting is late, and the yield is significant. Drought tolerance and frost resistance are mediocre.

Willow-leaved pear is a vigorous seed rootstock used for grafting pear cultivars in the arid regions of the North Caucasus, Armenia, and Turkmenistan. It has good compatibility with many cultivars. It is characterized by high drought tolerance, winter hardiness, and undemanding nature regarding soil conditions. Cultivated (local) forms and pear cultivars are used as seed rootstocks in all fruit-growing zones of the country. In the Volga region, seedlings of Belolistka and others are used, while in Ukraine and Moldova, Limonka and Ilyinka are used. Seedlings of cultivated forms and cultivars have good compatibility and advantages (precocity and yield of grafted cultivars) over wild forms. The winter hardiness and drought tolerance of the rootstocks in the zoned areas are high.

Vegetatively propagated rootstocks for pear include common quince, in particular the forms "A" (Angers), Provence, and BA23 (C29-1), which propagate well by layering. Due to insufficient winter hardiness, quince is used as a rootstock only in the southern fruit-growing zone.

It is recommended to graft the following pear cultivars onto clonal quince forms: Bon Chrétien Williams, Curé, Beurré Hardy, Beurré Diel, Beurré Morettini, and Alexandrine Douillard. Other cultivars should be grafted using compatible pear cultivars as interstocks. Quince "A" (Angers) is a medium-vigour rootstock compatible with certain pear cultivars.

The rootstock is moisture-loving, not winter-hardy, and tolerates temporary flooding and a high water table. On quince "A" rootstock, trees are relatively salt-tolerant. In calcareous soils, they suffer from chlorosis. Trees begin fruiting in the third to fifth year after planting. Their productivity is high.

Provence quince is a medium-vigour, more drought-tolerant, and salt-tolerant rootstock compared to quince "A", but it is incompatible with many pear cultivars. Under irrigation on fertile soils, plantations on Provence quince produce high yields.

Quince BA29 (C29-1) is a semi-dwarfing rootstock compatible with most pear cultivars and undemanding regarding soil conditions.

Quince rootstocks. Seedlings of local resistant quince forms and cultivars are used. Compatibility with all cultivars is good. Trees grafted onto quince seedlings are low-vigour, precocious, highly productive, relatively salt-tolerant, and tolerate some waterlogging of the soil.

Cherry and sweet cherry rootstocks. A number of common rootstocks are used for these species, in particular seedlings of Mahaleb cherry (St. Lucie cherry) and wild sweet cherry. In some regions, seedlings of resistant local forms and cultivars are used.

Mahaleb cherry (St. Lucie cherry) is a vigorous seed rootstock for sour cherry and sweet cherry. Compatibility with some sour cherry and sweet cherry cultivars is insufficient.

It is not permitted to graft the following cultivars onto Mahaleb cherry:

• sour cherries: English Early, Lyubskaya;
• sweet cherries: Ramon Oliva, Aprelka, French Black.

Mahaleb cherry seeds are characterized by high germination rates. Seedlings are vigorous, and with proper care, they are suitable for budding in the year of sowing. Sweet cherry and sour cherry trees on Mahaleb cherry are above average in growth vigour, relatively precocious, and productive. The winter hardiness and drought tolerance of Mahaleb cherry are high in the southern fruit-growing zone. It prefers fertile, light to medium-loam, well-aerated soils. Trees on this rootstock do not tolerate waterlogged or saline soils.

Wild sweet cherry is a vigorous seed rootstock used for sweet cherry and sour cherry in the southern fruit-growing zone. Trees on it are long-lived and highly productive, but slightly inferior in precocity to trees on Mahaleb cherry. Seed germination is relatively low.

There are known forms of wild sweet cherry whose seed germination approaches that of Mahaleb cherry. One such form with a high seed germination rate (50%) has been found. Sweet cherry seedlings are quite often damaged by coccomycosis, which significantly affects the output of nursery plants. No incompatibility with cultivated sweet cherry and sour cherry cultivars has been identified.

Sweet cherry seedlings prefer fertile, light, well-moistened, and well-drained soils with a deep water table. They grow worse on dry, sandy soils with a high lime content. The main disadvantage of sweet cherry seedlings is the excessively strong growth of the grafted trees, which makes their maintenance and harvesting difficult. The frost resistance of sweet cherry roots is lower than that of Mahaleb cherry and sour cherry.

Along with wild sweet cherry forms, seeds of the following cultivars are widely used as rootstocks: Drogana Yellow, Denissen's Yellow, and less frequently, Napoleon Bigarreau.

Common sour cherry is a moderate-vigour rootstock for sweet cherry and sour cherry. It grows well on shallow, dense, and moist soils, tolerates heavy and solonetzic soils, and sometimes suffers from chlorosis on high-carbonate soils. In terms of seed germination, growth vigour, and seedling uniformity, it is inferior to Mahaleb cherry. The bark separates less easily during budding than in Mahaleb cherry, and the separation period is shorter. Thus, a high yield of standard nursery plants on sour cherry is rarely achieved.

Rootstocks for sour cherry and sweet cherry: from seedlings to clones

Traditional seed rootstocks for sour cherry provide good compatibility with many cultivars, high winter hardiness, and rapid tree entry into fruiting. However, they have a serious practical drawback — abundant root suckers, the control of which requires constant manual labor. For the harsh climatic conditions of the Urals, Siberia, and the Northern Volga region, the steppe cherry remains the standard. This is a low-vigour, exceptionally winter-hardy, and drought-tolerant seed rootstock.

Clonal rootstocks help reduce variability in growth vigour and accelerate commercial fruiting. On heavy and moist soils, the medium-vigour domestic selection rootstock VP-1 performs excellently. Its fibrous root system securely anchors the tree in the soil. In the nursery, VP-1 propagates well by softwood cuttings, but propagation by layering and hardwood cuttings is noticeably worse.

Rootstocks for plum and cherry plum: selection for site conditions

Cherry plum is the main vigorous rootstock for plum in southern regions, which is also successfully used in the middle fruit-growing zone. Cherry plum seedlings are valued for the high germination of their pits, fast growth, and long bark-peeling period, which simplifies budding. The main drawback of this rootstock is the risk of root freezing in winters with little snow and the mass emergence of root suckers when roots are damaged or due to incompatibility with the scion. In nurseries, it is recommended to use verified forms with high compatibility rather than random cherry plum seedlings.

• Readiness of cherry plum seedlings for budding — 1st year of growth
• Application zones for steppe cherry — Urals, Siberia, Volga region

Selected cherry plum rootstock forms with high seed yield
No. 3, No. 7, No. 9, No. 15, No. 16

Abroad, instead of wild cherry plum, improved myrobalan forms are used: NA-102, NA-105, NA-1236, NAH-291, Chio-1, Chio-2, Chio-3. New clonal rootstocks are also currently being tested in different fruit zones. Among them, the dwarfing VVA-1 and Pixy, as well as the vigorous rootstock Kuban-86, stand out.

The best seed-propagated rootstocks from the common plum group are considered to be seedlings of Vengerka domashnyaya, Renklod zeleny, and Renklod Altana. In the more severe conditions of the Central, North-Western, and Volga regions, seedlings of hardy local cultivars — Renklod kolkhozny and Skorospelka krasnaya — are used. Tree growth on these rootstocks is moderate or vigorous, and yields are consistently high.

Other crops are also used as specific seed-propagated rootstocks:

• Damson (Ternosliva) — a medium-sized rootstock for the Volga region and the Central Black Earth region.
• Blackthorn (Sloe) — a dwarfing, very winter-hardy, and drought-tolerant rootstock, but it produces many wild suckers and is often incompatible with plum.
• Bessey cherry — a dwarfing rootstock for the Urals and Siberia, which is successfully propagated both by seed and vegetatively.

Seed-propagated rootstocks for apricot and peach: stability and compatibility

Apricot seedlings (zherdeli) are indispensable when growing plum on dry, gravelly, and skeletal soil, as well as in steppe areas with winters with little snow, where roots often freeze. This rootstock is vigorous, drought-tolerant, salt-tolerant, and does not form root suckers. However, when working in a nursery, keep in mind that the bark of apricot seedlings stops separating faster than that of cherry plum, and the root system is powerful but poorly branched. The rootstock tolerates heavy soil poorly and is more prone to wilting than plum or cherry plum.

Grafting common plum onto an apricot rootstock ensures high yields but requires strict selection of cultivars. Due to physiological incompatibility, mass breakage of the scion can occur at the graft union. An agronomist must exclude risky combinations in advance when establishing a nursery.

Cultivars poorly compatible with apricot	Cultivars well compatible with apricot
Vengerka azhanskaya	Rannyaya sinyaya
Vengerka italyanskaya	Renklod Altana
Plotnomyasaya	Renklod zeleny
Marmeladnaya	Anna Spath
Gorkusha No. 1	Victoria

Apricot seedlings are highly compatible with Chinese, Ussurian, and some Russian plum cultivars. Using apricot as a rootstock for cherry plum makes no practical sense due to poor graft take. For the apricot itself in arid regions, seedlings of common apricot remain the only reliable rootstock. In the Far Eastern gardening zone, it is replaced by the winter-hardy Manchurian apricot, and in the foothill regions of the south, cherry plum is used, with new cultivars being pre-tested for compatibility.

For peach orchards, the main rootstock consists of seedlings of local medium- and late-ripening cultivars, as well as semi-wild peach forms. In field trials, the bred cultivars Pamirsky No. 5 and Tikhoretsky No. 4 have shown excellent rootstock qualities. They are winter-hardy, high-yielding, and produce seeds with high-quality indicators.

Indicator of rootstock qualities (Pamirsky No. 5, Tikhoretsky No. 4)	Value
Seed germination	70 %

Trees on peach rootstock are high-yielding but extremely demanding regarding soil aeration. The rootstock does not tolerate waterlogging and heavy, waterlogged clay soil. Seedlings grow quickly, are suitable for budding in the year of sowing, and ensure a high yield of nursery plants on light, well-drained sites.

If soil conditions are not suitable for peach rootstock, alternative options are used:

• bitter almond seedlings — on calcareous and stony soils;
• cherry plum seedlings — on heavy, waterlogged soils (with mandatory compatibility testing of cultivars);
• plum seedlings of various cultivars — in foothill zones and on temporarily waterlogged sites;
• apricot seedlings.

Clonal rootstocks: domestic breeding vs. imports

Modern intensive orchards of stone fruits are primarily established on dwarfing clonal rootstocks. They accelerate the onset of tree fruiting and facilitate canopy management. However, blindly copying the foreign range of cultivars is risky. In comparative trials, introduced rootstocks were inferior to domestic clones in winter hardiness and adaptability.

According to the results of competitive trials under local conditions, the following imported rootstocks failed to pass the test:

• Brompton
• Damas 1869
• Colt
• Gisela No. 5
• Saint Julien
• Marianna
• Pixy

Domestic series of clonal rootstocks are created based on an extensive global gene pool of stone fruit crops, numbering about seven thousand genotypes. Breeding work allows for the selection of forms that are genetically adapted to unfavorable soil and climatic factors of specific growing zones. This guarantees the longevity of the orchard and stable yield accumulation.

Propagation and classification of domestic clonal rootstocks

Clonal rootstocks of stone fruit crops of domestic selection significantly facilitate the establishment of orchards due to their high plasticity during propagation. The following rootstocks have already been entered into the register of registered breeding achievements: VVA-1, Kuban-86, Evrika-99, VSV-1, Alab-1, Druzhba, Speaker, Fortuna, VTS-13, LTs-52, L-2, and VSL-2. Other promising forms, presented in the classification below, are currently undergoing state trials.

The main practical advantage of this group of rootstocks is their ability to be easily propagated by several vegetative methods. Depending on the technical equipment of the nursery, the optimal method can be selected for each clone: softwood, semi-hardwood, or hardwood cuttings, as well as horizontal layering. The correct choice of technology guarantees a high yield of rooted material — from 80 to 100%.

For planning nursery work, it is important to accurately assess the potential of each rootstock. The table below presents the classification of registered and tested rootstocks by vigor compared to seed analogues. This allows for determining in advance the optimal schemes for planting plants in the stool bed and calculating the demand for planting material.

• Yield of rooted rootstocks — up to 80–100%
• Growth inhibition on VVA-1 rootstock — by 50–60%
• Productivity increase on Kuban-86 — by 20–25%

Rootstock	Crops	Vigor, % of seed rootstock	Propagation methods
Vigorous (more than 80%)
Kuban-86	Plum, cherry plum, peach, apricot	100	Softwood, semi-hardwood, hardwood cuttings
Nakhodka	Plum, cherry plum	100	Softwood, semi-hardwood, hardwood cuttings
Fortuna	Plum, cherry plum, peach	80–90	Softwood, semi-hardwood, hardwood cuttings
Semi-dwarfing (60–80%)
Alab-1	Plum, cherry plum, apricot	75–80	Softwood, semi-hardwood, hardwood cuttings
Zelenaya Kolonna	Plum, cherry plum, apricot	75–80	Softwood, hardwood cuttings
Vesenneye Plamya	Plum, cherry plum, peach, apricot	70–75	Softwood, semi-hardwood, hardwood cuttings
Evrika-99	Plum, cherry plum, peach	60–70	Softwood, semi-hardwood, hardwood cuttings, horizontal layering
Speaker	Plum, cherry plum	70–75	Softwood, semi-hardwood, hardwood cuttings
Druzhba	Plum, apricot	75–80	Softwood, semi-hardwood cuttings, horizontal layering
L-2	Sour cherry, sweet cherry	70–80	Softwood, semi-hardwood cuttings
VTS-13	Sour cherry, sweet cherry	70–80	Softwood, semi-hardwood cuttings
LTs-52	Sour cherry, sweet cherry	65–70	Softwood, semi-hardwood cuttings, horizontal layering
Dwarfing (up to 60%)
VVA-1	Plum, cherry plum, peach, apricot	40–50	Softwood, semi-hardwood, hardwood cuttings
VSV-1	Plum, cherry plum, peach	50–60	Softwood, semi-hardwood cuttings, horizontal layering
VSL-1	Sour cherry, sweet cherry	40–50	Softwood, semi-hardwood, hardwood cuttings, horizontal layering
VSL-2	Sour cherry, sweet cherry	50–60	Softwood, semi-hardwood cuttings, horizontal layering, clonal micropropagation

Agronomic properties and limitations for orchard use

When choosing a rootstock for a specific site, it is necessary to evaluate not only the vigor of the tree but also its adaptability to soil and climatic conditions. The frost resistance of the root system, drought tolerance, or tolerance to waterlogging directly determine the longevity of the future orchard. Special attention should be paid to the compatibility of the rootstock with scion cultivars, as hidden incompatibility may only manifest several years after planting.

The VVA-1 rootstock is a hybrid of cherry plum and felt cherry. It is a dwarfing rootstock, reducing tree growth by 50–60%, and is characterized by high root frost resistance. The rootstock tolerates heavy waterlogged soils and temporary flooding well, and is resistant to wilting diseases and soil nematodes. It does not produce root suckers in the orchard and is suitable for all gardening zones.

The vigorous rootstock Kuban-86 (AP-1) is a hybrid of cherry plum and peach. It is resistant to heavy waterlogged soils, wilting diseases (verticillium wilt, cytosporosis, etc.), crown gall, and nematodes. The rootstock is characterized by good winter hardiness and drought tolerance, does not produce suckers, and is suitable for the southern gardening zone. Kuban-86 is compatible with all cultivars of Japanese plum, Russian plum, cherry plum, and European plum.

The Eureka-99 rootstock was obtained by crossing the Sapa cherry plum (sand cherry × Chinese plum) with the Otlichnitsa cherry plum. It is classified as semi-dwarf or medium-sized, reducing tree growth by 30–40%. The rootstock roots are winter-hardy and resistant to waterlogging, heavy soils, and wilt diseases. The rootstock does not produce root suckers, propagates excellently by cuttings and satisfactorily by horizontal layering in the southern gardening zone.

The dwarf VSV-1 rootstock was created through the hybridization of Bessey cherry and felted cherry. It reduces tree growth by 40–50% and is suitable for all gardening zones. Its roots are winter-hardy, and the plant itself tolerates moisture deficiency and wilt diseases well without producing root suckers. The rootstock propagates excellently by cuttings and horizontal layering.

The Alab-1 rootstock is a hybrid of cherry plum (Seedling No. 3) and apricot. This medium-sized rootstock reduces tree growth by 20–25% and is suitable for the southern and middle gardening zones. The rootstock roots are sufficiently winter-hardy, and the plant itself is resistant to heavy waterlogged soils and wilt diseases. It propagates well by green, semi-hardwood, and hardwood cuttings, without producing root suckers.

The Druzhba rootstock is a hybrid of the sand cherry (Bessey cherry) and apricot. This medium-sized rootstock reduces tree growth by 20–25% and is suitable for all gardening zones. Its roots are winter-hardy and resistant to waterlogging, heavy soils, and wilt diseases. The rootstock does not produce root suckers and is compatible with all plum cultivars.

The Speaker rootstock was obtained by crossing the Sapa cherry plum (sand cherry × Chinese plum) with cherry plum. It is medium-sized, reducing tree height by 25–30%, and is suitable for the southern and middle gardening zones. The rootstock roots are winter-hardy and resistant to heavy soils, waterlogging, and wilt diseases. The rootstock does not produce root suckers, propagates very well by cuttings, and is compatible with all tested plum and cherry plum cultivars.

The vigorous Fortuna rootstock was obtained by crossing the Vasilievskaya-41 cherry plum with a hybrid of Chinese plum and peach. Its growth vigor is 80–90% of a seedling rootstock. The rootstock is characterized by a high propagation capacity using green, semi-hardwood, and hardwood cuttings. It is well-suited for growing plum, cherry plum, and peach.

To establish plum orchards in the southern gardening zone, a vigorous (or medium-vigor) rootstock that reduces tree height by 10–20% is suitable. It demonstrates high resistance to heavy soils, waterlogging, and verticillium wilt, and completely fails to produce root suckers. The rootstock is compatible with all tested plum and cherry plum cultivars and propagates excellently by cuttings, especially hardwood ones.

Clonal rootstocks for intensive cherry and sweet cherry orchards

Modern stone fruit gardening is shifting toward clonal rootstocks, which allow for controlling tree dimensions and accelerating their entry into fruiting. The VTs-13, LTs-52, and VSL-2 rootstocks are adapted to dense, waterlogged soils and are resistant to root rot and bacterial canker. They are compatible with all sour cherry and sweet cherry cultivars, which simplifies the selection of scion-rootstock combinations.

• Height reduction on VSL-2 rootstock — by 50%
• Root winter-hardiness of VTs-13 and LTs-52 — down to -15 °C
• Planting density for VSL-2 — 800–1000 trees/ha
• Productive period of plantations — 15–18 years
• Time to entry into fruiting for VSL-2 — in 2–3 years

Rootstock and its origin	Growth inhibition (relative to seedling rootstocks)	Root winter-hardiness, °C	Start of commercial fruiting	Planting density, trees/ha
VTs-13 (Vladimirskaya × Cerapadus Michurina)	25–30% lower	Down to -15	2 years earlier than seedling rootstocks	600–800
LTs-52 (Lyubskaya × Cerapadus Michurina)	30% lower (more compact canopy)	Down to -15	In the 4th year (2 years earlier)	600–800
VSL-2 (Steppe cherry BS-2 × Japanese cherry)	50% lower	Down to -12	2–3 years after planting	800–1000

In the nursery, these rootstocks behave differently. VTs-13 propagates well by green cuttings, the meristem method, and horizontal layering, but does not propagate by hardwood cuttings. LTs-52 also roots with green and semi-hardwood cuttings, while hardwood cuttings do not survive. The VSL-2 rootstock propagates excellently by green and semi-hardwood cuttings, layering, and micropropagation, while hardwood cuttings show poor survival. In the nursery, the rootstocks quickly reach the stage for budding and maintain bark slippage for a long time (for VSL-2).

For nut crops, the methodology remains classic. The primary rootstock for cultivar walnuts in all zones of their cultivation is seedlings of local forms and cultivars of this species. For almonds, seedlings of bitter almonds also remain the main rootstock material in all regions of cultivation.