Technology of vegetative propagation of fruit crops using hardwood cuttings

Harvesting and preparation of hardwood cuttings

Propagation by hardwood cuttings is an effective way to obtain nursery plants of black and red currant, sea buckthorn, viburnum, quince, and cherry plum. The method is also excellent for apple rootstock">clonal rootstocks of apple (MM106, MM102) and stone fruits (Colt, Kuban-86, VVA-1). The technology is based on the biological ability of a plant stem to form adventitious roots.

Well-ripened annual shoots are suitable for cutting. When cutting branches from a mother plant, be sure to leave stumps for the formation of shoots in the next growing season. Make the lower cut slanted directly below a bud, and the upper cut straight and transverse.

• Length of harvested shoots — 20–30 cm
• Shoot diameter — more than 6 mm
• Height of stumps on the mother plant — 5–7 cm
• Distance from the top bud to the cut — 2 cm

Depending on the cutting method, hardwood cuttings are divided into three types: straight, with a "heel" (with a piece of wood from the previous year), and mallet-shaped (with a short piece of an older branch). Cuttings with a "heel" and mallet-shaped ones root significantly better than standard straight ones. For this reason, it is recommended to use them for hard-to-root species.

Planting dates and rooting technologies

Planting dates directly depend on the climate in your region. In temperate zones with stable snow cover, cuttings are harvested and planted into the soil in autumn. In harsh conditions with a fast, dry spring, harvesting is carried out in autumn or early spring, and planting in spring before bud burst. Regardless of the timing, the upper part of the cuttings is treated with paraffin to protect against drying out, and the lower part with growth regulators.

To stimulate rhizogenesis, growth regulators are used: IBA, NAA, IAA, or its potassium salt. The dosage of the preparation is selected individually, taking into account the ability of the specific species to root. Additionally, grooving is applied — making longitudinal cuts in the bark on the lower part of the cutting without damaging the wood.

For autumn harvesting, the temperature conditioning method can be used to stimulate callus formation. Basal cuts are treated with stimulants, after which the cuttings are kept in a moist environment. According to field tests, this technique is effective only with subsequent autumn planting. If cuttings are planted in the spring after winter storage, preliminary stratification worsens rhizogenesis or has no effect on it.

1. In autumn, cut the hardwood cuttings.
2. Treat their basal cuts with root-promoting preparations.
3. Keep the cuttings in a moist environment at a temperature of 18–21 °C for 4–6 weeks to stimulate callus formation.
4. Plant the prepared material into the soil in autumn or place it in storage for spring planting.

For planting, choose areas with loose soil. The cuttings are placed vertically or slightly slanted, leaving only one bud above the soil surface. The distance between plants in a row should be 5 cm, and row spacing is calculated based on the dimensions of the available equipment. During the rooting and growing season, the soil is regularly irrigated and loosened.

The ability to root depends on the level of endogenous auxins in the tissues of the cuttings. The higher the activity of these stimulants in the lower part of the shoot, the faster the roots are formed. According to the test results of four apple rootstocks, root-forming ability is distributed as follows:

Apple rootstock	Root-forming ability and biological activity of auxins
MM102	Highest
SK1	Intermediate
SK3	Intermediate
M9	Lowest

It has been established that in hard-to-root rootstocks, the "stimulants/inhibitors" ratio is within 0.10–0.30, and in easy-to-root ones, it is 0.6 and higher.

A conclusion was drawn about the possibility of using the "stimulants-inhibitors" index as a criterion for predicting the rhizogenic activity of hardwood cuttings of apple rootstocks and evaluating the effectiveness of agricultural practices aimed at enhancing their root-forming ability (Makarova, Bad, 1992).

The rooting ability of clonal apple rootstocks can also be diagnosed by the activity of peroxidase in the rhizogenesis zone of the cuttings.

Taking into account the noted diagnostic criteria, a biologically justified technology for propagating apple rootstocks using hardwood cuttings was developed at SKZNIISiV, ensuring a satisfactory yield of rooted plants with low labor intensity and material costs (Makarova, Bad, 1992).

Table 1 – Activity of endogenous regulators in rooted hardwood apple cuttings (Makarova, Bad, 1992)

Indicator	MM102	SK1	SK3	M9
Total stimulator activity*	117	57	55	46
Stimulators/inhibitors	1.10	0.48	0.31	0.26

* % of wheat coleoptile growth relative to control.

A critical element of this technology is the treatment of mother plants with the retardant TUR in June-July (a single spraying at a shoot length of 50–60 cm, concentration 0.6–0.7 %). The use of the retardant has a positive effect on the rooting capacity of cuttings harvested in the nursery. This fact is easily explained if we consider that TUR (CCC) activates the transport and accumulation of auxins in the basal part of the shoot (Fabbri et.al., 1986; Nagi, Tari, 1987).

Hard-to-root apple rootstock types such as M9, SK2, and others are most responsive to the use of TUR. At the same time, rootstocks with low sensitivity to the preparation (MM102, SK3, etc.) have been identified. They are characterized by a sufficiently high rooting capacity when propagated by hardwood cuttings without additional chemical treatment of the mother plants.

For rooting, the lower part of annual shoots with a diameter of 6–10 mm is used. The best time for harvesting cutting material is the second half of November. The rooting percentage of cuttings harvested at this time (plant dormancy period) is approximately 30 % higher than when selected at the end of October (period of plant transition from growing season to dormancy). Winter and early spring cutting dates do not ensure a sufficient yield of rooted apple rootstocks.

The technology for preparing and planting cuttings includes the following operations:

• The cutting is approximately 20 cm long.
• Its apical part is treated with antitranspirants (paraffin).
• In winter, the cuttings are stored at a temperature of 0–4 °C under conditions that prevent drying.
• The planting time is early spring.
• Substrate for rooting: soil, peat, sand in a 1:1:1 ratio.
• To activate rhizogenesis, heteroauxin (IAA) is used. The basal part of the cutting is dipped into the solution (immersion depth 1.5–2.0 cm, concentration 3–6 g/l, exposure 5–7 s).

The proposed technology for propagating apple rootstocks is essentially resource-saving, as hardwood cuttings are a byproduct. The technology is applicable under the various soil and climatic conditions of the North Caucasus. A logical continuation of research in this direction was the development of the growing technology for apple nursery plants through winter grafting onto hardwood cuttings of clonal rootstocks MM106 and MM102.

Of significant interest to nursery growers are the results obtained at the MSU department regarding the rooting ability of hardwood cuttings of apple clonal rootstocks 54–118 (semi-dwarf) and 62–396 (dwarf) in a plastic greenhouse, grafted with cultivars Wealthy, Severny Sinap, and Antonovka Obyknovennaya.

Indicator	Grafting on cuttings	Grafting on layers (control)
Nursery plant yield, %	47–64	88–97
Number of standard nursery plants, %	49–66	94–97

Despite the lower yield of nursery plants in the winter grafting on cuttings variant compared to grafting on layers, the use of hardwood cuttings is promising, as it allows obtaining standard one-year-old nursery plants of apple in one season, i.e., reducing their growing period by a year.

Propagation by softwood cuttings is widely used in production. Softwood cuttings can be used to propagate clonal rootstocks of apple, peach, and individual cultivars of apple, pear, cherry, plum, apricot, as well as raspberry, blackberry, sea buckthorn, chokeberry, edible honeysuckle, actinidia, currant, gooseberry, magnolia vine, and juneberry in artificial mist conditions with the use of growth regulators.

Softwood cuttings of many species, harvested from young mother plants, root well. During ontogenesis, tissue water content and water-holding capacity, as well as the activity of metabolic processes, decrease in plants.

In connection with this, structural changes are observed in them related to a decrease in the degree of tissue meristematization, causing a decline in the rooting capacity of cuttings. This feature is clearly expressed in hard-to-root plants.

The regeneration of adventitious roots largely depends on the location of the cutting itself on the plant and on the shoot. Thus, cuttings harvested from shoots of the lower canopy tier root better than cuttings from shoots of the upper tier.

Apple cuttings from shoots in the tree's fruiting zone are characterized by a low ability for root regeneration, while cuttings from water sprouts are, conversely, highly capable. Cuttings harvested from root suckers possess a high capacity for root formation. The latter, as is known, develop on roots from adventitious buds. Their appearance indicates a slowing of plant aging processes. As a result, cuttings of sucker origin are characterized by a high rate of root formation and good development of the root system. They also differ by early bud break and vigorous shoot growth.

Cuttings from vegetative shoots root better than those from fruit-bearing formations. Therefore, the agrotechnics of mother plants should be aimed at excluding their flowering and fruiting.

Softwood cutting	Shoot used to obtain cuttings
Softwood cuttings planted in greenhouse soil
Rootstock obtained from a softwood cutting

Figure 4 – Obtaining nursery plant material of apple from softwood cuttings

It is known that cuttings harvested from axial shoots root less effectively than those from lateral ones. This fact is easily explained by plant physiology. Axial shoots are characterized by a high content of protein and other nitrogenous substances and a low content of carbohydrates. An excess of nitrogenous substances leads to the inhibition of root primordia formation and decay of cuttings during rooting.

Rooting processes are largely related to the position of the cutting on the shoot axis. A shoot undergoes significant morphological, anatomical, and physiological-biochemical changes throughout its annual development cycle. Lower leaves and internodes usually grow for a short period and reach insignificant sizes. The middle part of the shoot is characterized by the most active and prolonged growth. In this regard, it is advisable to use cuttings from the lower part of the shoot for earlier cutting, and from the apical part for later cutting.

During the rooting process of softwood cuttings, the leaf plays a decisive role. The formation of new tissues and subsequently organs – roots is associated with an increase in the physiological activity of the rooting part of the shoot. During this period, the leaf, which is the main photosynthetic organ of the plant, provides the cutting with plastic and other substances. Without leaves, the ability of softwood cuttings to form roots is lost. Considering this, to enhance rhizogenic activity, it is necessary to create regimes that increase the intensity of photosynthesis and reduce leaf transpiration. This result is achieved by using artificial fog.

Fine misting of water over the site of cutting rooting, which is achieved with the help of misting installations, allows for changing the technology of softwood propagation. As a result of using artificial fog, it is possible to significantly improve the lighting conditions for the cuttings, and consequently, photosynthesis.

In softwood cuttings of some plant species, the regeneration of adventitious roots is well expressed, while in others it is weak. Based on this indicator, plants are divided into difficult-to-root, medium-to-root, and easy-to-root.

Such a division is conditional, since depending on the age of the mother plant, the condition of the shoots selected for propagation, the timing of cutting, and rooting conditions, the same plant can show varying ability for root regeneration. However, even when observing optimal cutting times and rooting regimes, softwood cuttings of plants of different species do not root equally.

An inverse relationship has been established between rooting ability and peroxidase activity in softwood cuttings of the genus Rubus (Upadyshev, Guskov, 1995). The use of this biochemical criterion allows for predicting the ability of plants for vegetative propagation and is of great interest for nursery science.

Among fruit and berry crops of the middle zone of the Russian Federation, black and red currant, raspberry, blackberry, chokeberry, sea buckthorn, hardy kiwi (actinidia), magnolia vine, and juneberry propagate relatively easily by softwood cuttings. Among gooseberries, cherries, plums, as well as clonal rootstocks of pome and stone fruits, there are cultivars (forms in the case of rootstocks), some of which root easily, others medium, and others with difficulty.

Easy-to-root gooseberry cultivars include Sadko, Rodnik, Russky, Smena, Slivovy, Pioner, Rekord, Yubileyny, Cherny Negus, Houghton, as well as a number of new promising domestic cultivars with thornless or slightly thorny shoots, which are distinguished by resistance to unfavorable factors, high yield, and high content of biologically active substances (Orlenok, Severny Kapitan, Kolobok, Captivator, etc.).

Among cherry cultivars, the easy-to-root group includes Shubinka, Vladimirskaya, Pamyat Lavrushina, Polevka, Zakharovskaya, Sklyanka Rozovaya, Rastunya, Kostychevka, Raspletka, Studencheskaya, and Zolushka. The following cultivars can be successfully propagated by softwood cuttings under artificial fog conditions: plums – Skorospelka Krasnaya, Vengerka Moskovskaya, Pamyat Timiryazeva, Iskra, Fioletovaya, Evraziya 21, Viktoriya, Volzhskaya Krasavitsa, Alenushka; apples – Pepin Shafranny, Pepin Litovsky, Melba, Shafran Kitayka, Altaysky Golubok; pears – Osennyaya Yakovleva, Naryadnaya Efimova, Dada, Chizhovskaya, Malgorzhatka Russkaya, Kolkhoznaya, Moskovskaya.

In Michurinsk, a large group of new clonal apple rootstocks bred by V.I. Budagovsky has been identified: 54–118, 57–146, 57–233, 57–257, 57–490, 57–545, 62–396, the rooting ability of which reaches 80–95%. The T-273 Bystretsovsky apple rootstock, obtained at the All-Russian Selection and Technological Institute of Horticulture and Nursery (VSTISP) by B. A. Popov and N. F. Seregin, also features good rooting ability of softwood cuttings.

A whole range of clonal rootstocks for stone fruits propagates easily: cherries – P-3, P-7, VP-1, PN-11–59–2; plums – OKD, OD-2–3, AKU-2–31, OP-23–23, OPA-15–2, E-13–27, SVG-11–19, 140–1, etc.

The rooting ability of cuttings of this group of plants is high and reaches 70–100%. The process of root formation in them proceeds uniformly. Roots are formed 2–4 weeks after planting the cuttings. In black currant and sea buckthorn, under favorable conditions, roots can appear even faster – on the 5th–8th day after planting.

Over a relatively short period, a large number of adventitious roots (up to 8–12 of the 1st branching order) form on the cuttings. On blackcurrant cuttings, especially when treated with growth regulators, up to 40 or even more roots are formed. Apple clonal rootstock cuttings of types MM106 and 62–396 form up to 60 roots or more on average per cutting.

Cuttings of this group are characterized by good bud break and shoot growth. The magnitude of growth depends on the species, cultivar, cultivation technique, weather conditions, etc. By the end of the growing season, shoots on cuttings of most easily rooting crops reach 20 cm or more. The root system in them is well-branched and fibrous.

The group of moderately rooting plants includes the following cultivars:

• gooseberry – Finik, Moskovsky krasny, Varshavsky;
• cherry – Griot ostgeymsky, Apukhtinskaya, Sklyanka rozovaya;
• plum – Vengerka obyknovennaya, Skorospelka novaya, Ochakovskaya zheltaya, Izobilnaya.

For cuttings of this group of plants, the root formation process is less active, lasting 6–8 weeks, and the root system and aerial part of the plants develop more weakly than in easily rooting ones.

Softwood cuttings of most European cultivars are difficult to root:

• gooseberry – Bochenochny, Angliysky zheltiy, Triumph, Victoria;
• cherry – Lyubskaya, Krasavitsa Severa, Shirpotreb chernaya, Kentskaya, Molodezhnaya, Malinovka;
• plum – Renklod ternovy, Renklod kolkhozny, Skoroplodnaya, as well as a number of cultivars of apple, pear, rowan, hazel, filbert, and other nut crops.

On cuttings of these difficult-to-root plants, roots usually form very slowly over 6–8 weeks or more. The number of rooted cuttings is insignificant (30% or less). A small number of roots (1–5) develop on the cuttings. Shoot growth in the year of rooting is most often absent.

The difficulty in rooting softwood cuttings is a biological problem.

A deeper study of the biology of mother plants, internal and external factors of shoot growth, and rooting regimes will contribute to the full expression of the potential root-forming capabilities of plants.

In the practice of vegetative propagation of plants, various types of softwood cuttings are used.

Depending on the degree of lignification of the shoot, softwood cuttings are divided into herbaceous and semi-hardwood. Herbaceous softwood cuttings are more often used for propagating flower plants, while semi-hardwood ones, which are distinguished by their elasticity, are used for propagating fruit and berry crops.

By length, softwood cuttings are divided into single-bud (or leaf-bud) and multi-bud cuttings. Single-bud cuttings consist of a short segment of a growing stem with one axillary bud and a leaf. Multi-bud cuttings have several buds and leaves. The length of such cuttings is from 5 to 20 cm. Recently, cuttings 25–35 cm long or more have also been used, which by the end of the growing season usually develop significantly better compared to short cuttings. Single-bud cuttings are used for propagating easily rooting plants, for example, currants, blackberries, and raspberries. The use of this type of cutting allows for faster plant propagation.

The optimal timing for taking cuttings ensures a high percentage of rooting, the fastest formation and growth of roots, bud break, as well as high responsiveness of cuttings to treatment with plant growth regulators and, subsequently, greater plant viability. The optimal timing for taking cuttings is determined by physiological readiness and a specific morpho-anatomical structure of the shoots.

One of the indicators of shoot readiness for cutting is their maturity. For the expression of the root-forming ability of cuttings, a certain degree of maturity is necessary, which is usually associated with the lignification of tissues and is determined:

• visually by the elasticity of the shoots (they do not break when bent, but spring back);
• histochemically with an evaluation based on a scoring system.

By this time, the xylem is sufficiently developed and stains pinkish-red with phloroglucinol.

Physiological state of shoots and timing of taking cuttings

The ability of cuttings to form roots depends directly on the rate of lignification of tissues. The faster this process occurs, the faster the cells age and the worse the root system regenerates. For example, in the difficult-to-root cherry cultivar Lyubskaya, tissues lignify significantly faster than in the easily rooting cultivar Shubinka. The timing of taking cuttings is always tied to the intensity of shoot growth, which is selected individually for each crop.

For most fruit crops (apple, quince, cherry, plum, cherry plum, peach, filbert, and hazel), the optimal time for taking cuttings coincides with the phase of most active shoot growth in length. During this period, the shoots are maximally saturated with water and contain many organic forms of nitrogen, phosphorus, and natural growth stimulators with a minimal amount of inhibitors. Visually, this phase is determined by the shoot tip: the more simultaneously growing leaves there are, the higher the daily growth rate.

Crop (cultivar)	Daily shoot growth, cm
Cherry (Shubinka)	0.7–2.1
Cherry (Lyubskaya)	0.5–0.8
Apple (MM106)	0.2–0.4
Apple (PK–14)	0.7–0.8
Apple (Budagovsky's Paradise)	0.4–0.6

For a number of crops, the optimal development phases for taking cuttings differ:

• Pear, gooseberry, sea buckthorn — softwood cuttings root better in the phase of declining linear shoot growth.
• Honeysuckle — strictly in the phase of complete cessation of shoot growth.
• Guelder rose and rose hips — in the phase of mass flowering and its decline.
• Raspberry — during the regrowth period of young suckers (this phase occurs twice per growing season: in late May and mid-summer).

Black currant, American gooseberry cultivars, magnolia vine, and actinidia are suitable for propagation by cuttings throughout a long period of the growing season. Under conditions of a greenhouse using artificial fog and growth regulators, this period can be significantly extended, starting the work in earlier phenological phases. This ensures an increased rooting percentage and accelerated plant development.

Harvesting rules and nursery productivity

Shoots are harvested only from healthy, true-to-type mother plants with high vigor. The productivity of a nursery depends directly on the planting density and the biological characteristics of the propagated form.

• Nursery planting pattern — 80 x 25 cm
• Average yield of cuttings — 500–600 thousand/ha
• Yield of cuttings for specific forms — up to 1 million/ha

1. Cut shoots during the morning hours when tissue hydration is at its maximum. If the nursery is located close to the propagation area, harvest the material in small batches throughout the day.
2. Immediately place the cut material into protective containers: plastic bags, buckets with water at the bottom, or baskets lined with damp burlap or film.
3. Transport the harvested shoots quickly to the propagation site, avoiding overheating and desiccation.

Preparation of cuttings and treatment with stimulants

The prepared material must be delivered to the propagation site as quickly as possible. Each batch of shoots is marked with a label indicating the cultivar and place of harvest. The size of the cutting directly affects callus formation and rooting. Cuttings that are too long evaporate a lot of moisture due to an excess of leaves, which reduces tissue hydration and impairs survival. Small cuttings 2–3 cm in length root slowly and lag in development.

• Optimal cutting length — 15–25 cm
• Planting depth in substrate — 1.5–2.0 cm
• Zeolite consumption per 1 sq. m — 200 kg
• Pressure in nozzles — 200–400 kPa

When taking cuttings from the apical part of the shoot, it is mandatory to leave at least one fully formed leaf. Underdeveloped leaves do not participate in photosynthesis but only consume the limited nutrient reserves of the cutting. Leaf blades are usually not shortened. Only in case of space deficiency in the greenhouse can leaves of large-leaved cultivars be trimmed by 1/3 or 1/2.

Cuts are made according to the rules: the bottom one 0.5–1 cm below a bud, the top one just above it. For ease of planting, 1–2 leaves are removed from the bottom part of the cutting. For crops with short internodes, such as sea buckthorn and gooseberry, 3–4 bottom leaves are removed.

To accelerate root formation, growth regulators are used. The bases of the cuttings are immersed 2.0–2.5 cm into a solution of indole-3-butyric acid (IBA) with a concentration of 25–50 mg per 1 L for 12–24 hours. Indole-3-acetic acid (IAA) and naphthaleneacetic acid (NAA) are also used. IAA is rapidly degraded in tissues, providing only a short-term metabolic effect on the base of the cutting.

Substrate selection and conditions for rooting

After treatment, the cuttings are rinsed in clean water and planted into the substrate. The traditional mixture of peat and sand in a ratio of 1:1 or 2:1 in greenhouses with misting systems must be changed annually. Its physical and chemical properties deteriorate quickly, and pathogenic microflora accumulates. Mineral substrates, such as expanded clay, perlite, or vermiculite, are used as an alternative.

The technology for setting up beds requires layering the materials. Fine crushed stone or gravel is placed at the very bottom level for drainage. Above it, a layer of fertile soil at least 12–15 cm thick is placed. A working layer of mineral substrate 3–4 cm thick is poured on top of it.

Excellent results can be achieved by using zeolite or its mixtures. This natural mineral contains potassium, calcium, magnesium, aluminum, iron, and about 16 trace elements, including molybdenum, zinc, copper, and boron. Before planting, the zeolite substrate is saturated with nutrients, calculated for long-term operation without additional top dressing during the growing season. The thickness of the zeolite layer at an application rate of 200 kg per 1 sq. m is 20 cm.

Nutrient component	Dose range (% by mass of zeolite)
Nitrogen	0.1–0.3
Phosphorus	0.1–0.4

When planting, green cuttings are buried in the substrate to a depth of 1.5–2.0 cm. The distance between rows is maintained within 8–10 cm, and 4–5 cm is left between plants in a row. To maintain leaf turgor before roots form, constant humidity is created by automatically supplying water in a mist-like state at a pressure of 200–400 kPa.

Temperature is strictly controlled during rooting. For most species of fruit crops, it should be 24–27 °С at the base of the cuttings and 21 °С in the leaf zone. This temperature distribution is achieved by laying a POSKhV heating cable or warm water pipes under the soil. Root formation in green cuttings begins 20–40 days after planting.

Intensive cultivation technologies and greenwood cuttings

After planting greenwood cuttings in a greenhouse, it is necessary to maintain high humidity and temperature using artificial mist until rooting occurs. As soon as roots appear, the plants begin to be hardened off by regular ventilation. The nursery stage takes about four months, after which part of the planting material is ready to be transferred to the nursery. For the winter, the nursery area is covered with a 4–5 cm layer of peat, or the plants are dug up and stored in sand or polyethylene bags at a temperature of 0–3 °С.

To accelerate the propagation of clonal rootstocks and cultivars of apple, cherry, plum, red and black currant, the "forcing" method is used — preliminary preparation of mother plants under a plastic cover. This technique stimulates active shoot growth and increases its duration. In the conditions of the central region, shoot length reaches 30–45 cm by the end of May, and by this time, cherry and plum trees have already formed a second wave of growth. The vegetative productivity of mother plants under plastic increases by 1.5–4.7 times compared to open ground.

• Increase in productivity of mother plants under plastic — by 1.5–4.7 times
• Increase in rooting of apple and cherry — by 10–48 %
• Yield of nursery plants from plastic greenhouses — 100–120 thousand units/ha
• Profitability of "green" grafting — up to 126 %

Using elongated cuttings (30–45 cm) allows for the propagation of clonal rootstocks of apple, cherry, and currant in two cycles per season. Early greenwood cuttings manage to produce sufficient growth in the same year, which allows their tops to be cut off and reused for rooting. For valuable cherry and plum cultivars that are difficult to root, "green" grafting onto easily propagated clonal rootstocks is effective. It reduces the nursery plant growing time by 1–2 years and increases labor productivity by 40 %.

Crop	Yield of cuttings from 3-year-old mother plants, thousand units/ha
Clonal apple rootstocks (II forms)	805–2350
Black currant	7400–12000

Propagation by root cuttings

Propagation by root cuttings is based on the ability of root segments to fully restore the above-ground part and the root system. This method is most promising for clonal rootstocks of apple, pear, and quince. Root material is harvested in three periods: when uprooting clonal rootstock mother plants, during late autumn digging of nursery plants, or in early spring before sap flow begins, when the maximum supply of nutrients is stored in the roots.

• Survival rate of M9 rootstock cuttings — 97 %
• Yield of standard M9 rootstock layers — 88 %
• Length of M9 root cutting — 8–10 cm
• Thickness of M9 root cutting — 6–10 mm
• Stratification temperature — 15–20 °С

1. Cut root cuttings, observing the direction of the cut polarity.
2. Sort the cuttings by thickness and tie them into bundles of 50 or 100.
3. Place the cuttings for winter storage in sand, peat, or sawdust at a temperature of about 0 °С. When harvesting in spring, send the material immediately for stratification.
4. At the end of March or early April, transfer the cuttings for stratification into crates with sawdust at a temperature of 15–20 °С. Water the substrate 2–3 times a week.

After about 10 days of stratification, callus and the primordia of primary roots form on the lower ends of the cuttings, while shoots about 1 cm long appear on the upper ends. After this, the material is ready for planting in the soil. Planting is carried out during the first days of spring field work. For the nursery, prepare beds 20–30 cm high with loose, fertile soil. The cuttings are planted according to a 5 x 10 cm pattern, with the upper end of the cutting protruding 1 cm above the soil surface. Immediately after planting, the beds are mulched with a thin layer of fine sawdust or humus.