Sugar beet

Agrotechnical importance

Due to the fact that sugar beet requires deep soil tillage, application of fertilizers and good care of crops, it serves as a valuable predecessor for many crops in crop rotation, increases the productivity of field crop rotations; the field after it remains clean from weeds, and a sufficient reserve of moisture remains in the soil. According to data of the All-Russian Research Institute of Sugar Beet and Sugar named after A. L. Mazlumov (ВНИИСС), or the former Ramonskaya experimental station, the yield of crops sown after sugar beet is on average 8-19% higher than those sown after winter crops.

After harvesting sugar beet, a large amount of plant residues remains in the field, which serve as organic fertilizer or for fodder purposes in fresh, ensiled or dried form.

The introduction into crop rotation of such a root crop as beet is inseparably connected with the transition to a more advanced system of field cultivation, with the improvement of land tillage and livestock feed, etc.

V. I. Lenin. The Development of Capitalism in Russia. Collected Works, vol. 3.

Root system

The root system of an adult sugar beet plant includes a thickened main root and a dense network of thin branches extending from the main root. It penetrates into the soil to a depth of 2.5 m and spreads in width within a radius of 40-50 cm. Root mass averages 400-800 g.

The main root, or root crop, has a cone-shaped elongated form, slightly compressed from the sides, usually unbranched. The root crop is divided into:

• root crown, or shortened stem, which develops fully above the soil surface and bears leaves; it has the lowest sugar content;
• neck, or hypocotyl, or subcotyledonous knee, is the part of the root crop without leaves and lateral roots; it accumulates the greatest amount of sugar — up to 19-20%;
• the root proper, the lower part of the root crop, or tail, usually has a conical shape, on which lateral roots are formed, arranged in two longitudinal rows; it accounts for 70-85% of the root length.

In cross-section of an adult root crop, one can see the central vascular-fibrous bundle (“star”) and alternating concentric layers (rings) of conducting bundles that communicate with the conducting tissue of leaves. Each of these conducting bundles consists of xylem, which is large lignified cells through which water and dissolved nutrients move from soil to leaves, and phloem (bast), which is thin-walled cells through which sugars and other photosynthesis products are transported in the opposite direction from leaves to roots. Between the rings of conducting vessels are parenchyma cells in which sugars are deposited.

Anatomically, in species of the genus Beta spp., primary, secondary and tertiary root structure are distinguished. In primary structure, in the center of the root are vessels of primary xylem and phloem, separated by cells of ground tissue — parenchyma. Together they represent the central conducting cylinder of the root. Around the conducting cylinder is the pericycle — an educational tissue consisting of one layer of parenchyma cells. Thus, the pericycle separates the cells of the primary root from the central conducting cylinder.

After the plant’s first true leaves appear, secondary changes begin in the root. In parenchyma cells of the central cylinder, two cambial arcs form, which bend parallel to the primary phloem, reach the pericycle and then take the form of a circle. Cells arising from the cambial ring toward the center form secondary xylem (wood); toward the periphery of the root — secondary phloem (bast). Pericycle cells form secondary cortex, consisting of a thin layer of cork tissue. Formation of secondary cortex and cork tissue leads to shedding of the primary cortex, called root molting. After molting, roots thicken; for this reason, formation of plant stand density, i.e., thinning, is carried out in compressed periods, and the more seedlings per meter of sowing row, the earlier thinning begins, in order to reduce the influence of intraspecific competition.

After root molting, tertiary changes begin in the secondary cortex. In the parenchyma of the secondary cortex, a second cambial ring forms. After xylem elements are deposited inward and phloem elements outward in the form of bundles with parenchyma cells between them, the second cambial ring ceases activity. It is replaced at some distance outside by a third cambial ring, which forms as a result of division of the next generations of the same educational cells that gave the first ring. By the same scheme, fourth, fifth, etc. rings form. In modern varieties the number of cambial rings reaches 12.

Thus, thickening of the root crop occurs as a result of formation of new rings and growth of inter-ring parenchyma. In varieties with high sugar content, the number of rings is, as a rule, higher than in high-yielding ones, and inter-ring parenchyma is narrower, roots are smaller.

In the root crop, vascular bundles that formed first are located in the center, while the youngest are on the periphery. In the leaf rosette, on the contrary, old leaves are external and young ones internal. In this connection, in the crown of the root crop, vascular bundles intersect, which leads to an increase in relative fiber content.

Leaves

Sugar beet leaves are large, entire, petiolate. Shape changes with age: young leaves have short petioles and rounded blades; older ones have elongated petioles and a heart-shaped blade. The surface of the leaf blade may be smooth or corrugated, wavy, and depends on variety and growing conditions.

Depending on the location of the leaf blade, flat, prostrate leaves, which almost lie on the ground, and upright leaves directed upward are distinguished. The latter are characteristic of high-yielding varieties. Plants with an upright rosette are less damaged during mechanical care of crops.

Length of one leaf can reach 50-70 cm. Leaves account for 30-50% of the harvest mass.

Flowers

Sugar beet flowers are of pentamerous type, bisexual, have a greenish perianth and a three-lobed stigma. They are located in leaf axils along the stem and its lateral branches in groups of 2-6 as whorls, which form an inflorescence — a loose spike (whorled spike-like raceme).

Flowers of monogerm beet are located one at a time. Flowering lasts from 20 to 40 days. Nectar has a honey smell.

Beet is a strict cross-pollinator, pollinated mainly by wind, partly by insects. Pollen can spread over a distance of 4-5 km. Therefore, considering this property, and also the absence of an incompatibility barrier between sugar, fodder and table beet, spatial isolation must be observed between seed crops, sugar beet seed plants, mother and factory crops.

Fruit

The fruit of sugar beet is a nutlet; it has a thick two-layer pericarp of loose lignified tissue. Fruits form a seed ball, or beet infructescence (often called seeds), consisting of 2-6 fruits. Size of seed balls depends on number of fruits. When fruits ripen, sepals become woody and fuse with the hard shell. The top of a mature fruit has a relatively flat or slightly convex lid, under which lies a horizontally located seed. Monogerm seed balls have one nutlet.

Mass of 1000 seed balls varies from 15 to 50 g, monogerm — 20 g. The seed accounts for 25-30% of the seed ball mass.

Monogerm beet has an advantage, as labor costs for thinning seedlings are significantly reduced, allowing full mechanization of crop care operations.

Seed

The seed is covered with a brown shiny shell. The embryo is coiled almost into a ring around the perisperm, where the reserve nutrients are located. The embryo consists of two cotyledons, between which is the plumule, hypocotyl and embryonic root. For sowing, angular seed balls of gray-yellow color are suitable.

Temperature requirements

Sugar beet is distinguished by the ability to use reduced temperatures of spring and autumn periods. It is relatively resistant to frost.

Seed germination begins at a temperature of 2-5°C; viable seedlings appear at 6-7°C. But germination at such temperature is slow; seedlings appear after 18-20 days. Increasing temperature helps reduce the period from sowing to emergence: at 10-12°C it is 12-14 days, at 15-17°C — 7-8 days. Uniform and strong seedlings are an important condition for high sugar beet yield.

Seedlings can withstand spring frosts down to -4...-5°C. In the fork stage, frosts of -3...-4°C are dangerous. After appearance of the first pair of true leaves, i.e., 6-8 days after emergence, sugar beet can withstand frosts down to -6...-8°C.

According to data from the physiology laboratory of VNIS, as crops advance north, bolting increases, which is explained by lower temperature, lengthening of daylight and saturation of light with long-wave rays.

According to results of a VNIS experiment conducted on growing sugar beet in a greenhouse at different temperatures, elevated temperatures reduce bolting. All plants in the warm chamber did not follow the path of reproductive development. Elevated temperatures retard vernalization processes, lengthen their periods and stop reproductive development.

Optimal temperatures for photosynthesis and growth of sugar beet are 20-23°C, but growth and sugar accumulation continue up to a temperature of 6°C in autumn. The sum of active temperatures in the first year of vegetation in the main beet-growing areas equals 2200-2400°C, in the north of the Non-Black Earth zone and in Siberia — 1800-2000°C, in southern regions — up to 3000°C.

Hot weather strongly affects plant water balance, resulting in depression of photosynthesis and increased respiration, accompanied by consumption of sugars and slowing of growth.

Moisture requirements

Sugar beet makes high demands on moisture from the first signs of vital activity, but at the same time is distinguished by drought resistance. For swelling and germination of seeds, which are enclosed in lignified pericarp shells, 120-170% water of the seed ball mass and air access are required.

The transpiration coefficient of sugar beet depends on nutrient, thermal, light regimes and other factors. It varies in different vegetation phases from 240 to 400. Sugar beet economically uses moisture, but total water consumption of 1 ha of crops is quite high due to formation of a large amount of dry organic mass. It is considered that for growing 100 kg of roots and the corresponding amount of leaves at an average yield of 40-50 t/ha, about 8 m³ of water is consumed (water consumption coefficient); per 1 hectare water consumption will be 3000-4000 m³. These data indicate the great importance of techniques aimed at accumulation and preservation of water in soil, and explain the high responsiveness of sugar beet to irrigation.

Maximum water consumption in sugar beet is observed during the period of intensive growth, i.e., in July-August. Optimal conditions for growth and formation of a high yield are soil moisture not less than 60-80% of minimum moisture capacity.

The transpiration coefficient of seed roots (beet planted in the second year) averages 725, which is significantly higher than in first-year beet. Total water requirement of one plant planted for seed, at 60% soil moisture depending on conditions and development of seed roots, varies from 30 to 75 l, or approximately 0.7-1.2 l per g of air-dry seeds.

Water requirement of seed roots and first-year beet during vegetation is different. In seed roots, intensive transpiration begins much earlier than in first-year beet, reaches a maximum usually in late June-early July (a month earlier than in factory beet), when flower stalks are thrown and until the end of flowering. This period accounts for flowering of seed roots. Optimal moisture for normal development of seed roots is 60-70% of minimum moisture capacity.

Reduction of beet yield in years of insufficient moisture is somewhat less than in other agricultural crops, which is due to the powerful, deeply penetrating root system, which begins to develop intensively in the first growth phases and allows plants to use subsoil water reserves from a depth of 2 m. Sugar beet is also distinguished by a long vegetation period and the ability to use late summer precipitation.

The following meteorological factors determine maximum sugar beet yield:

• with average spring onset, May, as the first month of vegetation, may not be humid;
• August should not be dry, but with good insolation and sufficient precipitation;
• heavy rains in September negatively affect harvest quality;
• warm September and especially October cause high sugar content of roots.

Light requirements

Sugar beet belongs to long-day plants with increased light requirements. Plant development and sugar accumulation strongly depend on duration and intensity of sunlight.

Lack of light leads to a sharp decrease in yield and sugar content of roots. Lack of light may be due to the influence of weeds.

During the sugar accumulation period, sugar beet is most demanding of light. 1 dm² of leaf surface under normal illumination accumulates about 12 mg of sugar per hour. Short changes of cloudy and sunny periods do not affect root growth and sugar content.

Sugar content depends on the number of sunny days in the second half of vegetation, i.e., in August and September, and sufficient moisture supply.

Soil requirements

Optimal for growing sugar beet are considered structural chernozem soils with high organic matter content, chestnut, gray and dark-gray forest soils, as well as lowland, floodplain and humus-rich meadow-bog soils. By mechanical composition, loamy soils are optimal. In conditions of the Non-Black Earth zone, it gives high yields provided a high level of agricultural technology, liming and a deep humus horizon.

It grows poorly on poor sandy and very heavy clay soils; on heavy soils roots begin to branch.

For sugar beet, a neutral or slightly acidic soil solution reaction is preferable (pH 6.5-7.5); it suffers from increased acidity pH< 6. Beet is distinguished by salt tolerance and is capable of giving high yields with good sugar content in roots on solonetzic soils. To obtain the same results on strongly saline soils, leaching irrigations and application of organic fertilizers are necessary.

Most scientists consider the optimal density of the arable soil layer to be 1.0-1.2 g/cm³ (1.0-1.3 g/cm³).

Sugar beet is also demanding on soil aeration conditions, especially during seed germination and root formation.

Normal groundwater level is considered 1.5-2 m from the soil surface.

Need for nutrients

Sugar beet requires a large amount of nutrients to form a harvest. According to data from experimental stations, with a yield of 30-40 t/ha roots and 15-20 t/ha leaves, 120-140 kg/ha nitrogen (according to other data 180-2401), 40-55 kg/ha phosphorus (according to other data 60-802), 150-200 kg/ha potassium (according to other data 210-2803) are absorbed from soil. For example, nutrient content in a harvest of 103.6 t/ha roots and 33.2 t/ha leaves was 477 kg nitrogen, 114 kg — P₂O₅, 498 kg K₂O (X. Baidich, Vinnitsa oblast, Ukraine). On average, for formation of one ton of roots and the corresponding amount of leaves, 5-6 kg N, 1.5-2 kg P₂O₅ and 6-7.5 kg K₂O are needed.

Application of a full dose of mineral fertilizers for sugar beet in the main application or in split doses is equivalent in effectiveness.

Sugar beet is also demanding of calcium and microelements, primarily boron and manganese.

Nitrogen

Good nitrogen nutrition promotes growth of leaves and root. Nitrogen deficiency manifests as a light-green color of the aboveground part of the plant, early yellowing and death of old leaves. With nitrogen deficiency, first the veins of vascular bundles and adjacent tissue turn yellow, while parts of the leaf distant from veins may remain light-green. Unbalanced excess of nitrogen leads to decreased sugar content and white sugar yield.

Phosphorus

With phosphorus deficiency, growth is delayed, root mass decreases, and sugar accumulates in leaves. Young leaves and the root crop provide their phosphorus need through its reutilization from old leaves. The reutilization process also occurs with sufficient phosphorus supply to plants, but less actively.

With phosphorus deficiency from the very beginning of vegetation, seedlings lag strongly in growth and acquire a dull dark-green color. With severe phosphorus deficiency, dark-brown spots appear on leaves, edges of lower leaves become dark-brown and die.

As a rule, in the main beet-growing regions of Russia, soils are characterized by low phosphorus content.

Potassium

Potassium helps increase plant resistance to drought and frost.

Potassium deficiency manifests as drying of the edge of the leaf blade, starting from the most productive middle leaves. Potassium deficiency leads to a sharp decrease in sugar content of roots.

Calcium

Calcium deficiency leads to weakening and cessation of plant growth and, above all, of the root system. At the same time, characteristic chlorosis appears on leaves: leaves acquire a mottled color, areas between veins become pale, while veins themselves remain green.

Microelements

Sulfur deficiency manifests in sugar beet as brown spots on leaves and their yellowing.

Iron deficiency in soil manifests as leaf chlorosis and yellowing.

Manganese participates in accumulation and movement of sugars from leaves to root, stimulates growth of new tissues in growth points. It also participates in absorption of iron from soil and prevents leaf chlorosis.

Boron deficiency leads to development of a sugar beet disease called heart rot, or dry rot. With this disease, the growth point and rudiments of the youngest leaves die. Young leaves curl, their petioles and veins become brown or black, then they wilt and die. Wilting and death develop from the inner part of the rosette to the outer. Outer leaves turn yellow or become covered with spots resembling rust, wilt and die. Subsequently, root tissues are destroyed — first near the neck, then deeper. The rotten tissue becomes dry and crumbly. Sugar beet consumes a large amount of boron during the period 13-14 weeks after sowing; in other periods the need for boron is low.

Nutrient uptake

Sugar beet absorbs nutrients throughout the whole vegetation, but the need for them differs in individual vegetation periods.

In the initial period of growth and development, sugar beet has the greatest need for nitrogen and phosphorus. By the middle of vegetation, uptake of all nutrient elements reaches a maximum. In the second half of vegetation, sugar beet plants absorb more than 25% of all nitrogen and about 40% of potassium. The need for phosphorus remains as in the middle of vegetation.

Germination

During germination of sugar beet seeds, the rootlet and hypocotyl are the first to grow. They break through the seed coat and come out. The cotyledons remain inside the fruit for some time; through them, nutrients stored in the seed continue to nourish the young sprout. Then the cotyledons come to the soil surface, quickly acquire a green color, and begin supplying the plant with photosynthesis products, which is especially important in the initial growth period. Any damage to cotyledon leaves causes significant damage to the future harvest. After formation of 6-8 true leaves, the cotyledons quickly dry up.

The cotyledon phase, or “fork,” lasts 6-8 days. Then true leaves appear from the central bud.

Leaf development

Each new leaf appears in early summer every 2-3 days, in mid-summer — every 1-2 days. During vegetation, a plant can form up to 60-90 leaves. Total leaf surface area reaches 3000-5000 cm², which is 3-5 times the area of soil occupied by the plant itself. Rate of leaf growth and power depend on provision of plants with water and nutrients, primarily nitrogen.

Depending on plant development, appearing leaves differ in size, shape and duration of life. The most productive are leaves of middle tiers, appearing in summer, from the 10th to the 25th. They develop quickly and persist up to 60-70 days. Lifespan of the first leaves is 20-25 days. Active photosynthetic activity of a leaf is about 25 days.

In the first half of summer, leaf growth proceeds faster than their death, so tops mass increases. Greatest leaf development is noted in the second half of July and August, then their mass begins to decrease rapidly. By harvest time, the share of leaves is 30-60% of root mass.

Optimal leaf surface area of sugar beet is 40-50 thousand m²/ha.

Leaf death occurs faster with moisture deficiency.

Development of root and root crop

In the first days of plant development, the primary root develops slowly. But in the fork phase its length reaches 15-20 cm and it begins to grow in the plane of cotyledons with lateral branches having a dense network of root hairs.

With appearance of first true leaves, the hypocotyl and main root begin to thicken; length reaches 30 cm. In this connection, thinning in dense crops must be completed by the beginning of root crop formation.

Development of the root crop and root system is linked with leaf formation: the earlier and more leaves form, the faster the main root grows.

Periods of sugar beet development

In the first year of sugar beet vegetation, three main periods are distinguished:

1. formation of leaf surface and root system; the period is about one and a half months;
2. intensive growth of leaves and root crop, lasts more than two months; daily root growth reaches 10 g;
3. intensive sugar accumulation, continues the last month of vegetation; daily root mass growth is 5 g, sugar content increases by 0.07-0.1% per day.

Duration of each period is conditionally considered about 50 days.

In the second year of vegetation, plants form the root system more slowly; it penetrates into soil to a depth of 1.5 m only by the time seeds ripen.

Bolting

In the first year of sugar beet life, dormant buds are laid in leaf axils. Most of them are laid at high temperature. Its further decrease to 0-8°C leads to their development. Under natural conditions, this decrease should occur in winter, and then in spring of the second year these buds produce flowering shoots. However, this process can also be observed in the first year of plant life, resulting in the phenomenon of sugar beet bolting.

If a flowering shoot forms in the first year of vegetation, bolting roots are obtained. Bolting usually manifests with short vernalization at very early sowing, cold and prolonged spring and long daylight. Bolting leads to decreased sugar content of roots, partial lignification of tissues and decreased root mass. Processing such roots is more difficult, and during storage clamp rot develops. Early bolting is especially undesirable.

The main way to prevent bolting is timely sowing and use of resistant varieties.

When growing beet for seed in the second year, the opposite phenomenon is possible, in which plants do not flower and do not produce seeds. Such plants are called “stubborn.” The causes of this phenomenon are considered to be physiological unpreparedness of roots for further development. It is caused by action of elevated temperatures, early harvesting, autumn and spring drying of mother roots, elevated storage temperature, and shallow planting.

Monogerm diploid varieties and hybrids

Yaltushkivska monogerm (N — Normal, i.e., yield-sugar direction of breeding). The variety was bred by Yaltushkiv breeding station of VNIS using hybridization and selection. High-yielding; sugar content is not inferior to released varieties of multigerm beet. Released in Russia, Moldova, Georgia, and Ukraine.

Yaltushkivska monogerm 30 (N). Interline hybrid, bred by Yaltushkiv experimental breeding station of VNIS. Highly plastic; sowing qualities of seeds good. Released in Stavropol Krai, as well as in Ukraine.

Yaltushkiv hybrid (N). Bred by Yaltushkiv breeding station by hybridization of varieties Yaltushkivska monogerm and Ramonskaya 06. Released in the Central Black Earth zone and Volga region, as well as in Ukraine.

Uladivska monogerm 35 (N). Variety bred by Uladovo-Lyulinets experimental breeding station of VNIS by selection of monogerm material of the station. High-yielding; sowing qualities of seeds good. Relatively resistant to diseases and bolting. Released in Ukraine.

Bilotserkivska monogerm 34 (N). Variety obtained at Bilotserkivska experimental breeding station of VNIS by selection from monogerm materials of the station. Sugar content above 17%, separateness reaches 100%, seed germination above 80%. Released in Ukraine.

Yubileiny (N). Hybrid bred by the Central Breeding-Genetic and Verkhnyatska experimental breeding stations of VNIS by hybridization of male-sterile monogerm diploid materials with multigerm diploid pollinator in ratio 4:1. High-yielding, sugar content above 17%, resistant to bolting. Released in Ukraine.

Biysk monogerm 12 (N). Variety obtained by Biysk experimental breeding station by selection from Yaltushkivska monogerm. Released in Altai Krai.

Ramonskaya monogerm 9 (N). Variety bred by ВНИИСС (Ramon) by selection from monogerm varieties of Bilotserkivska experimental breeding station and Yaltushkiv support point. Released in the Central Black Earth zone.

Lgov hybrid (E — Ertrag — yield direction of breeding). Variety bred by Lgov experimental breeding station by intervarietal hybridization of Bilotserkivska monogerm with multigerm variety Lgovskaya 078. Released in the Central Black Earth zone and Mordovia.

Kyrgyz monogerm 25 (N). Variety bred by Kyrgyz experimental breeding station for sugar beet of the Kyrgyz НИИ of Agriculture using the method of individual selection from variety Kyrgyz monogerm 8. Released in Kyrgyzstan.

Uladivska monogerm 20.

Veselopodolyanska monogerm 29.

North Caucasus monogerm 42.

Bilotserkivska monogerm 40.

Ramonskaya monogerm 32.

Ganusovsky hybrid 8.

Meusotnensky hybrid 9.

Mezhotnensky hybrid 18.

Vnisovsky hybrid 12.

Marathon.

Matador.

Perla.

Sonia.

Extra.

Cermo.

Kiva.

Gala.

Lena.

Moldavian monogerm 41.

Ramonskaya monogerm 32.

Ramonskaya monogerm 47.

Ramonskaya MS 68.

RMS 70.

RMS 73.

Epos.

RMS 78.

Chernozemets.

RBMS 17.

Ramonskaya MS 46.

Biysk monogerm 50.

Druzhba MS 34.

Lgovskaya monogerm 52.

Orbis.

Multigerm varieties

Ramonskaya 06 (N). Variety bred by ВНИИСС. High-yielding, sugary, ecologically plastic, early ripening, bolting weak.

Ramonskaya 036 (E). Variety bred by ВНИИСС by intervarietal hybridization from Ramon varieties. High-yielding, bolting weak, sugar content medium. Released in Bashkiria, Tatarstan, and Kazakhstan.

Verkhnyatska 038 (N). Variety bred by Verkhnyatska experimental breeding station of VNIS. High-yielding, plastic, increased sugar content. Released in the forest-steppe part of Ukraine and Polesia, and Armenia.

Verkhnyatska 103 (N). Variety bred by Verkhnyatska experimental breeding station of VNIS. Increased productivity; represents a genetic mixture of progeny of two ancestors. Released in Ukraine.

Uladivska 752 improved (N). Variety bred by Uladovo-Lyulinets experimental breeding station of VNIS. Increased resistance to bolting. Released in the forest-steppe part of Ukraine, Belarus, Latvia and Lithuania.

Polyhybrids

Bilotserkivsky polyhybrid 1 (N). Obtained at Bilotserkivska experimental breeding station of VNIS by crossing tetraploid Bilotserkivska monogerm with Ramonskaya 06. Highly productive, monogerm. Released in Ukraine.

Bilotserkivsky polyhybrid 2 (N). Bred by Bilotserkivska experimental breeding station of VNIS by crossing monogerm tetraploid form of Bilotserkivska monogerm with diploid variety Verkhnyatska 031 in ratio 3:1. Released in Ukraine.

Kuban polyhybrid 9 (N). Obtained by the North Caucasus branch of VNIS and the Institute of Cytology and Genetics by natural hybridization of tetraploid form Verkhnyatska 038 with diploid variety Pervomaiskaya 028. High-yielding, increased sugar content. Released in Krasnodar Krai, North Ossetia, Stavropol Krai, Chechnya and Ingushetia.

Pervomaisky polyhybrid 10 (N). Bred by the North Caucasus branch of VNIS and the Institute of Cytology and Genetics by crossing tetraploid form of variety Yaltushkivska monogerm with diploid variety Pervomaiskaya 028 in ratio 3:1. Released in Krasnodar and Stavropol krais, North Ossetia, Chechnya and Ingushetia, also in Armenia.

Bilotserkivsky polyhybrid 19.

Bilotserkivsky polyhybrid 30.

Vnisovsky polyhybrid 5.

Kyrgyz polyhybrid 18.

Ramonsky polyhybrid 23.

Ramonsky polyhybrid 25.

Ramonsky polyhybrid 28.

Foreign varieties

Claudia (1997, Germany). Released in regions 4, 5, 7, 8, 9, 10.

Loretta (1997, Germany). Released in regions 4, 5, 6, 7, 8, 9.

Grazia (1999, Germany). Released in regions 4, 5, 8, 9, 10.

Kristella (2000, Germany). Released in regions 3, 5, 7, 9.

Laurencia (2001, Germany). Released in 6, 7, 9, 10.

Juvena (2003, Germany). Released in 3, 5, 7, 9.