Jerusalem artichoke
Jerusalem artichoke (Helianthus tuberosus).
Jerusalem artichoke (Helianthus tuberosus L.), or earth apple, is an industrial fodder agricultural crop.
Other names: girasole, topinambour, sunchoke, Jerusalem artichoke. The latter name, “Jerusalem artichoke,” is not related to the artichoke (Cynara scolymus), and it does not grow in Jerusalem. This name probably derives from the Italian word <span lang="it">girasole</span>. The tubers taste somewhat like artichoke.
Economic importance
A unique feature of Jerusalem artichoke is the formation of inulin, a fructose polymer, which averages about 15% of fresh weight (or up to 30–40% of dry matter) and is the main storage carbohydrate. Therefore, it is mainly cultivated as an industrial crop for inulin production. Hydrolysis of inulin yields fructose. The tubers also serve as raw material in the production of alcohol, wine and wine vinegar, fodder yeast, and beer.
The tubers are suitable food for diabetics, since this form of carbohydrates can be used by people with impaired glucose metabolism. The tubers are prepared in the same way as potatoes or eaten raw in salads. Table varieties are grown for food purposes.
The tubers and green mass of the earth apple can be used for fodder purposes.
The stems and leaves are rich in vitamins; the dry matter content reaches 25–30%, including most carbohydrates with a small amount of fiber. The protein of the dry matter contains all essential amino acids. The green mass is also rich in inulin, which under the action of animals’ gastric juice is converted into fructose.
Green mass for fodder is used fresh; it is relatively well eaten by all animals. On average, 100 kg of green fodder corresponds to 20–25 fodder units and contains 1.8 kg of digestible protein. The green mass of Jerusalem artichoke is of great importance as supplementary feed in fur-farming and hunting farms.
Hay meal and grass meal, as well as silage, are made from the green mass. Because Jerusalem artichoke stems contain up to 25–30% (dry matter) carbohydrates, and with leaves 15–20%, the green mass ensiles easily. The silage stores well and is eaten by cattle, sheep, goats and other animals. 100 kg of silage corresponds to 18–25 fodder units. 1 fodder unit contains 80–90 g of digestible protein. Chemical composition of the silage: water — 75.2%; protein — 2.6%; fats — 0.5%; fiber — 6.6%; nitrogen-free extractives — 13.7%; minerals — 3.0%.
Jerusalem artichoke tubers contain up to 21–30% dry matter, including 10–18% inulin, 5–7% fructose, about 2–4% protein, carotene, B vitamins and minerals. The vitamin content is 2 times higher than in potato tubers. In nutritional value they are not inferior to potatoes: 100 kg contain 23–30 fodder units and 1.5 kg of protein; they are readily eaten by animals and poultry. In quality and nutritional value they are not inferior to silage from maize and sunflower.
Jerusalem artichoke provides the earliest feed for pigs. Grazing them on earth apple plantations in early spring makes it possible to almost completely avoid other types of feed. Weight gains of piglets when fed tubers increase by 20–30%, and when animals are fattened, the quality of lard improves. For this reason, in our country at the stage of introduction into production this crop became most widespread on pig farms, and in the 1980s in the Baltic states, where bacon pig farming was developed.
Tubers for fodder are used raw, steamed or boiled. In winter, combined silages are prepared from them, thereby lengthening the period of feeding tubers and avoiding their long storage, which is often difficult.
It can be used for medicinal purposes for people with diabetes, anemia and atherosclerosis, as it helps lower blood sugar and restore vision.
In cultivation, topinsunflower is known — a hybrid of Jerusalem artichoke and sunflower, which hardly differs from Jerusalem artichoke. It is used in the same way as earth apple. Unlike the latter, it does not clog the crops of subsequent crops and can be placed in crop rotations.
Jerusalem artichoke can be used as green manure.
A crop similar to Jerusalem artichoke is Indian breadroot (Psoralea esculenta Pursh, family Fabaceae), also known as prairie potato. This uncultivated plant is native to North America and produces tuber-like roots with a starch content of more than 60% of dry matter.
History of the crop
Endemic to North America, the plant can be found in the wild in the north of the central part of the USA, in adjacent regions of Canada and on the east coast of the USA. Native Americans used the tubers long before European colonization. In the early 17th century, Jerusalem artichoke was brought to Europe, where it quickly established itself and gained some importance as a vegetable. However, in Europe its main use was reduced to feeding livestock.
It reached Russia in the 18th century.
Cultivation areas
Large sown areas of earth apple are found in France, Poland, Hungary, the Scandinavian countries, Great Britain, the USA, Japan and China.
The world sown area is approximately 0.5 million ha.
In the USSR this crop was cultivated everywhere, but on limited areas.
In Russia it is grown on small areas in the North Caucasus, in the Non-Chernozem and Central Chernozem zones, the Volga region, Siberia and the Far East. As an ornamental plant it can be found everywhere.
Due to its response to the light regime, Jerusalem artichoke in northern Russia is cultivated mainly as a silage crop, in the south as an industrial crop for tubers, and in the middle belt both are practiced.
Yield
Yield varies considerably; usually it is about 15–20 t/ha. However, under favorable conditions the yield reaches 40 t/ha.
Under Russian conditions the yield is 50–60 t/ha of fodder mass or 10–15 thousand fodder units per 1 ha. In the Caucasus and Central Asian countries, the yield of green mass is 20–100 t/ha and of tubers 20–130 t/ha, depending on nutrition and moisture conditions.
In the central regions of Russia, Moldova, Belarus and Ukraine, the yield of green mass varies from 20 to 75 t/ha, and of tubers from 20 to 45 t/ha. In the Non-Chernozem zone and the north of the European part of Russia, as well as in the Baltic countries, Jerusalem artichoke produces 35–80 t/ha of green mass and 4–14 t/ha of tubers. In some regions of Siberia and the Far East, the yield of green mass is 30–140 t/ha and of tubers 9–20 t/ha.
Botanical description
Jerusalem artichoke is a tuber-bearing perennial plant belonging to the family Asteraceae, genus Helianthus L. The genus Helianthus includes over 100 species, but only two of them are of agricultural importance: Helianthus annus L. (sunflower) and Helianthus tuberosus L. (earth apple). It is a perennial plant, but is grown as an annual.
Jerusalem artichoke has erect, branching, well-leafed stems of green or slightly violet color and 1.5–4 m in height. Bushiness ranges from 1 to 5 stems.
The leaves are pointed, large, coarsely pubescent, serrate along the edges, and have an ovate, elongated-ovate or broadly ovate shape on long petioles. In the seedling phase they form a rosette; in the budding phase, in the lower part of the shoot they are whorled, and in the middle and upper parts alternate.
The inflorescence is a head, as in sunflower, but smaller, 1.3–5 cm in diameter. The flowers are bright yellow; the inner ones are tubular, the marginal ones ligulate. The inflorescences are located at the tips of the main and lateral shoots. Depending on the degree of branching, the number of inflorescences varies from 1 to 50 per plant. Pollination is cross — by wind and insects.
The fruit is an achene, smaller than that of sunflower, cone-angular in shape, gray or brown with speckles. The weight of 1000 is 7–9 g. Achenes of late-ripening varieties ripen only in southern latitudes (Central Asia, Crimea, North Caucasus, Transcaucasia); early-ripening ones ripen in the Central Chernozem zone, sometimes near Moscow. Seed propagation is possible only in a hot climate; in our country it is practiced only for breeding.
The root system is fibrous; with seed propagation it is taprooted and well branched. The roots penetrate to a depth of 2 m; the working surface is 6–8 times greater than that of potato. Roots account for 4.6–8% of the total plant mass.
Shoot branching can be aboveground and underground. Aboveground shoot branching can be acropetal, that is, from the axils of the lower opposite leaves, and basipetal — from the axils of alternate leaves. In the underground part of the shoot, stolons are formed — underground lateral shoots. The 4–6 upper internodes of the stolon thicken, turning into a tuber. In varieties, the stolon length is 5–40 cm. The shorter the stolons, the more compact the tuber nest.
The tubers are fleshy, pear-shaped, oblong-oval or spindle-shaped, with a smooth or lumpy surface, which makes harvesting and removing soil difficult. The color ranges from white to yellow, sometimes red or violet. The fleshy interior is white with a crisp and watery texture. The eyes are convex. On one plant of breeding varieties, the number of tubers reaches 20–30; in semi-wild forms, up to 70. Tuber weight is 10–100 g, depending on the variety and growing region. Unlike potatoes, Jerusalem artichoke tubers do not have a corky layer (they are covered with a thin skin), so they store worse and are most often harvested in spring. When planted in soil, it usually produces one sprout.
Biological characteristics
Temperature requirements
The plants are adapted to regions with a temperate climate and a frost-free period of 4–5 months. Jerusalem artichoke is distinguished by resistance to high and low temperatures.
The heat requirements of early-ripening varieties of earth apple are similar to those of mid- and late-ripening potato varieties, that is, the sum of active temperatures during the growing season is 2000 °C; for mid- and late-ripening varieties — 2500–2800 °C (Department of Crop Production, MAA named after K. A. Timiryazev).
Aboveground organs can withstand short-term frosts down to -8 °C, tubers down to -12 °C in air and down to -35 °C in soil under snow cover. These properties determine the possibility of growing Jerusalem artichoke as far as 65° S latitude.
Germination begins at a soil temperature of 5–6 °C; more uniform germination occurs at 8–10 °C. Shoots appear after 3–4 weeks.
This crop also tolerates high temperatures well. Unlike potatoes, Jerusalem artichoke does not suffer from heat degeneration.
The favorable temperature range is from 18 °C to 26 °C; higher temperatures reduce yield. Plants die from frost.
Moisture requirements
Thanks to its powerful, deeply penetrating root system, earth apple is distinguished by increased drought resistance among tuber crops. However, earth apple gives high tuber yields under conditions of a warm climate and sufficient moisture or irrigation. Water consumption is quite high — 100 cm or more during the growing season.
The greatest resistance of plants to lack of soil moisture is manifested in the seedling phase and at the beginning of stolon formation. Critical periods occur at the beginning of stolon thickening and bud formation, that is, in the second half of summer, when in most regions of Russia moisture conditions improve.
Light requirements
Jerusalem artichoke does not have high light requirements, but strong thickening can lead to a decrease in the yield of green mass, and especially of tubers.
It belongs to short-day plants. The longer the growing season, the more strongly the variety’s response to shortening day length is manifested. Therefore, early-ripening varieties react little to a short photoperiod and can form inflorescences and ripe achenes even near Moscow. Under the relatively long day of the central and northern regions of the country, the yield of green mass increases, while the yield of tubers for most varieties decreases.
Soil requirements
Jerusalem artichoke can grow on all soil types and soil differences, except solonetz, solonchak and waterlogged soils. Loamy and sandy loam soils with a deep cultivated arable layer, loose and permeable, are considered optimal for its cultivation.
It tolerates acidic soils poorly; the optimal acidity is <abbr title="Hydrogen ion concentration">pH</abbr> 6–7; it is responsive to liming. It grows poorly on heavy, strongly moistened soils. Plants are sensitive to poorly drained soils, especially during tuber development.
Due to its low economic value, Jerusalem artichoke is often grown on poor soils with minimal nutrition, moisture and care. Despite its reputation as a plant that does well in unfavorable conditions, in reality the yield under such conditions is low. Given fertile, well-drained sandy loam soils, good care and nutrition, this crop is capable of producing very high yields.
Plant nutrition
Despite its unpretentiousness, earth apple responds well to improved nutrition conditions.
From 1 t of Jerusalem artichoke green mass, 3 kg N, 1.2–1.4 kg P2O5 and 4.5 kg K2O are removed from the soil. From 1 t of tubers — 2–2.5 kg N, 2–2.5 kg P2O5 and 7 kg K2O (G. V. Ustimenko).
Yield increases significantly when fertilizers are applied. Applying 30 t/ha of manure in the first year increased the green mass yield by 9.6 t/ha and tubers by 1.5 t/ha; in the second year by 17.1 t/ha and 3.7 t/ha, respectively (MAA named after K. A. Timiryazev).
Nitrogen enters Jerusalem artichoke plants less intensively than in potatoes (Peoples’ Friendship University named after Patrice Lumumba). Its maximum content is noted only by the time of harvest. In plants, there is an intensive outflow of phosphorus from aboveground organs and roots to the tubers. By the end of the growing season, up to 50% of P2O5 is concentrated in the tubers. The maximum amount of potassium enters the plants by the end of the summer period. As growth stops and tissues age, the potassium content in plant organs begins to decrease. With the tuber harvest, up to 70% of the potassium that entered the plants is removed.
Vegetation
Jerusalem artichoke tubers can overwinter in the soil, which has given grounds to classify it as a perennial plant. Every year at the end of the growing season, the aboveground organs of earth apple die off, and the tubers survive winters everywhere thanks to the polysaccharides they contain. In spring they sprout, producing 1–3 shoots from each tuber and forming a bush.
Shoots originating from buds on the tuber grow quickly, forming tall stems and leaves. Strong plants reach a height of 4 m. From the base of the stems, a well-branched but shallow root system develops. Early growth is often vigorous enough to outpace and shade competing weeds. Typical composite flower heads are 4–8 cm in diameter and yellow. Seeds are formed but are not used for propagation, since the resulting plants are not uniform in type.
The duration of the Jerusalem artichoke growing season varies from 120 to 200 days.
Plant organogenesis is determined by the formation at the ends of the axial shoot of two storage organs — vegetative (tubers) in the underground part of the stem and generative — heads at the top. In the initial period of vegetation — before stolon thickening — shoot growth is slow; before tuber formation, daily stem increments increase, and during stolon thickening they slow down. The greatest stem growth is noted in the second half of summer, when up to 50% of the green mass yield is formed; daily plant height increments then reach 4–5 cm. After that, growth processes slow down, plants form buds and flowers, and the outflow of assimilates from leaves to shoots and tubers increases.
A decrease in day length initiates tuberization simultaneously with the transfer of carbohydrates from leaves and stems to developing tubers. Tuberization causes cessation of vegetative growth and of the leaf apparatus; some plants begin to wither.
In the central and southern regions of Russia, tuberization begins in June–July; in the northern regions, in August. The period when stolon thickening begins depends on hereditary varietal characteristics, changes in photoperiod and fluctuations in day and night temperatures. Tuber yield formation occurs mainly in the autumn months — in September and October (in the south also in November) until frost.
Jerusalem artichoke is characterized by high ecological plasticity. High green mass yields with optimal water and nutrient regimes are possible in almost all regions of Russia, whereas high tuber yields are possible only in regions with a hot summer period and a long warm autumn.
Cultivation practices in the first year of plantation establishment
Crop rotation
Varieties and hybrids of Jerusalem artichoke are cultivated in farm and field crop rotations, as well as in diversion fields. Small regrowth after plantation liquidation is destroyed with herbicides or other methods.
The period of use of perennial plantations is from 5 to 15 years.
The optimal predecessors when establishing a perennial plantation are considered to be perennial and annual leguminous grasses, row crops, cereals, and grain legumes. In perennial culture, the greatest stable yields are given by varieties with short stolons, for example, Nakhodka and Skorospelka.
Earth apple is not placed after sunflower, root crops and other crops affected by sclerotinia. To prevent the spread of this disease, the plantation is established no earlier than 4–5 years after these crops. On pig farms, it is advisable to locate Jerusalem artichoke plantations near the farms so that pigs can be grazed.
Fertilization
The rates of fertilizer application for Jerusalem artichoke are determined by soil fertility, the planned yield, and moisture conditions.
When establishing a perennial plantation, it is recommended to apply 30–60 t/ha of manure (preferably under the predecessor) or other organic fertilizers, as well as 60–90 kg/ha of a.i. of nitrogen, phosphorus and potassium. For the forest-steppe zone — N60-90P90K90.
Organic, phosphorus and potassium fertilizers, and on acidic soils also lime, are applied in autumn under the main plowing; nitrogen fertilizers — in spring under replowing or cultivation.
In subsequent years, mineral fertilizers are applied annually. Organic fertilizers are applied every 4–5 years.
Soil tillage
Tillage for establishing a perennial Jerusalem artichoke plantation is similar to tillage for potatoes and root crops.
After stubble disking, fall plowing is carried out to a depth of 23–25 cm; on sod-podzolic soils — to the depth of the humus layer.
In spring, after the soil reaches physical ripeness, harrowing of the fallow is carried out. Then in southern regions no-moldboard tillage is performed; in northern regions, shallow moldboard plowing or deep disking. On heavy loamy soils, deep no-moldboard loosening is recommended; on light and medium loams, cultivation or disking. On heavy soils, layer-by-layer treatment can be carried out.
Before planting, cultivation is done.
Planting
Planting dates
Jerusalem artichoke is usually planted in spring; in southern regions autumn planting is possible.
Planting should be carried out as early as possible in the growing season (simultaneously with the beginning of sowing early spring crops, or 7–10 days earlier than potatoes) in order to maximize the period of vegetative growth before tuberization. A short growing season limits leaf growth and carbohydrate accumulation, which leads to low yields.
Methods and rates of planting
The main planting method is wide-row with row spacing of 60–150 cm.
The distance between tubers in the row is determined by soil fertility, tuber size, moisture conditions, and varietal characteristics, and is 30–60 cm (usually 30–35 cm).
In areas of sufficient moisture on fertile soils, the recommended planting density is 50–60 thousand/ha of tubers; on medium-fertile soils — 40–45 thousand/ha; in arid conditions — 30–35 thousand/ha.
For varieties with increased branching, the distance between plants is increased or a square planting scheme of 60×60 cm or 70×70 cm is used. With small planting material, several larger tubers can be planted per unit area, which makes it possible to obtain the same yield as when planting large tubers.
Planting with whole tubers weighing 40–90 g is most advisable. In southern regions, where most tubers are usually larger, cut tubers can be used for planting. For autumn planting, cutting tubers is not recommended. In the north, where tuber size is usually 10–15 g, planting is done with 30–50% thickening.
The planting rate varies from 0.6–0.7 to 2.0 t/ha.
Tuber buds exhibit apical dominance, and freshly harvested tubers undergo a dormant period before sprouting. Raised beds, even if slight, improve subsequent tuber development and harvest. At the beginning of plant growth, soil is moved to the base of the stems, as a result of which the forming tubers develop at a depth of 10–25 cm from the surface.
For planting, freshly dug tubers are used, dug no earlier than 5 days before planting. If planting is delayed, they are covered with soil or sand to prevent wilting. Wilted tubers can be placed in water for 1–1.5 days, after which their mass is restored.
Planting is usually done with potato planters; on small areas, manually into furrows pre-cut with a hiller.
On soils heavy in particle-size composition, the planting depth is no more than 5–6 cm; on medium soils — 6–8 cm; on light soils — 8–10 cm. The depth is increased by 2–3 cm for autumn planting.
Crop care
Due to the long germination period, 2–3 pre-emergence harrowings are carried out on the crops to control weeds. Also, one harrowing is recommended on the shoots with light harrows.
At the beginning of the growing season, top dressing with nitrogen fertilizers can be carried out at a rate of 45 kg/ha of a.i..
When plants reach a height of 10–15 cm, inter-row cultivation begins; at a height of 30–40 cm, hilling is done.
To increase the yield of green mass, topping of plants, or cutting of the tops, is recommended. This technique promotes increased branching and leafiness of the stems, and also makes it possible to avoid the development of seeds competing with tuber growth.
Harvesting
The green mass yield increases until tuber formation begins. However, mowing it during this period is not recommended due to a sharp decrease in tuber harvest. When determining optimal harvesting dates, the aim is to obtain the maximum number of fodder units. Thus, for the southern regions of Russia the recommended time for mowing green mass is October — early November; in the northwestern regions — at the end of September; in the northern regions — at the end of August — early September. For silage, green mass can be harvested in the south during mass flowering, and in the Non-Chernozem zone 2–3 weeks before frost.
Silage combines are used for harvesting green mass. The cutting length for silaging is 5–6 cm. Mowing is recommended at a high cut of up to 15–30 cm; this is especially important in northern regions, where by the time of green mass harvesting the tubers have not yet grown and remain underdeveloped. As a result of the outflow of assimilates from the remaining stem part, which is of low fodder value, tuber yield increases.
For current feeding of livestock and for preparing combined silage, part of the tubers is harvested in autumn. But usually they are dug in spring (or the remaining majority is dug) before the buds in the eyes begin to sprout. On pig farms, pigs are grazed on the plantations for 10–15 days in early spring.
Tubers are collected in late autumn, when the stems completely wither or die from low temperatures. To facilitate harvest, the stems are cut. Tubers are difficult to collect because they are branched, and many of them break. Since thin-skinned tubers are easily damaged, careful handling is necessary during and after harvest. Even undamaged tubers are subject to rapid drying.
On light soils, tubers can be harvested with potato diggers or combines; on heavy soils, they are plowed out with a plow.
Following harvest, cultivation or 1–2 harrowings are carried out, with subsequent picking of the remaining tubers.
Storage
Jerusalem artichoke tubers store poorly in winter, quickly wilt, and are affected by fungal diseases. Therefore, usually a small part of the tubers is harvested in autumn and used for livestock feed or silage preparation, while the main part is harvested in spring, so as not to store a large number of tubers. Storage in the soil is possible where soils do not freeze and are well drained. However, if the dormant period is disturbed, sprouting may occur.
For storing tubers from autumn harvest, clamps, trenches or special rooms are used. For better storage, they are placed in layers of 10 cm, alternating with soil or sand.
Collected tubers can be stored for several months at a temperature of 0–2 °C and a relative humidity of 95%. Tubers stored at low temperatures have a sweetish taste, so before consumption they should be wilted at a warm temperature for several days to reduce the sugar content.
Cultivation practices in subsequent years
When cultivated on a perennial plantation, in spring before tuber harvest, N90P90K90 fertilizers are applied; every 3–4 years, 20–30 t/ha of rotted manure. In this case, fertilizers are well incorporated by the harvesting machinery. If the crops are for grazing, fertilizers are applied after grazing ends.
During harvest, part of the tubers is left for plantation renewal, approximately 8–10 pcs/m2. To prevent thickening of the stand, certain experience is required in harvesting a particular variety so as not to leave an excess number of tubers in the soil.
Shoots in crops of the second and subsequent years of plantation use appear somewhat earlier than in the first, but less uniformly due to differences in tuber depth in the soil. Harrowing is done before emergence and on the shoots.
When plants reach a height of 15–20 cm, the plantation is treated with row-crop cultivators, after which plants remain only in untreated places, thus marking the rows. Sometimes another technique is used: after tuber harvest, ridges are cut with a cultivator-hiller, marking the beds. During pre-emergence harrowing, the ridges are not completely leveled; later they serve as a guide for “blind” (pre-emergence) cultivations. A third method: when plants are 15–20 cm high, bouquets 10–12 cm wide with row spacing of 60–70 cm are cut using cultivators in cross directions.
Further care is the same as in the first year of use.
Plantation liquidation
By the 5th–8th year of use, the plantation begins to thin out, and the yield of green mass and tubers decreases. Therefore, in the last 1–2 years, annual grasses or their mixtures can be undersown at a rate of 100–120 kg/ha, which helps obtain a good green mass yield. When harvesting in June — early July of the last year of use with undersowing, the nutrients of the tubers are completely consumed, so if plowing is carried out immediately after early harvest, regrowth of Jerusalem artichoke (topinsunflower) usually does not appear. However, to be safe, annual grasses can be sown on this plot for one more year.
If rapid liquidation of the plantation is necessary, the aboveground mass is mowed in June–July, the tubers are dug up and fall plowing is carried out. The next year, crops for which herbicide application is planned are sown.
After complete harvest, small residual regrowth is destroyed by the following methods:
- when sowing a grain crop after earth apple, treatment with herbicides of the 2,4-D group is carried out;
- by sowing for 1–2 years peas, field pea, vetch, vetch-oat or another fodder mixture, followed by harvesting them for silage at the beginning of stolon formation;
- by mowing the regrowth at the moment when the nutrient reserves in the old tubers are exhausted and new tubers have not yet formed; this period falls in June — early July, followed by plowing and sowing annual grasses for green fodder and silage.
Any of these methods makes it possible to clean the soil well from tubers without using clean fallow.
Varieties
Nakhodka, Skorospelka (1965), Belaya urozhaynaya, Vadim, Kievskaya belaya, Volzhskaya 2, Leningradskaya, Interes (1986), Vylgortsky (1996).
In the USSR, work was carried out on interspecific hybridization of Jerusalem artichoke with sunflower. The hybrid was called topinsunflower, which is distinguished by a more compact nest and more uniform tubers, making it possible to mechanize harvesting and reduce losses. Topinsunflower can be introduced into crop rotation without clogging the crops of subsequent crops. In the tubers and green mass of some hybrids, the content of carbohydrates, including inulin, protein and other nutrients, is higher than in Jerusalem artichoke. Hybrids with higher cold and frost resistance and disease resistance were also developed. During hybridization, the phenomenon of heterosis occurs, which is preserved during vegetative propagation.
Topinsunflower hybrids: Hybrid No. 120, Hybrid No. 15, Topinsunflower violet, M-3, 58/6, VIR, Severny, Daugava.
Varieties of Jerusalem artichoke and its hybrids, depending on the ratio of green mass and tubers in the yield, are divided into types:
- silage type, with a high yield of green mass, which accounts for more than 70% of fodder units;
- tuber type, grown for industrial purposes, with tubers accounting for 40–45% of the yield;
- tuber-silage and silage-tuber types, giving a high yield of both tubers and green mass. This type is the most widespread.
Depending on the duration of the growing season, varieties and hybrids are divided into:
- early-ripening;
- mid-ripening;
- late-ripening.
Interspecific hybridization makes it possible to develop early-ripening forms for various uses, which may make it possible to expand the cultivation area of the crop.
References
1. Vavilov P. P., Gritsenko V. V., Kuznetsov V. S. et al. (1986). Crop Production. Ed. Vavilov P. P. 5th ed., revised and enlarged. Moscow: Agropromizdat.
2. Kolomeichenko V. V. (2007). Crop Production/Textbook. Moscow: Agrobusinesscenter.
3. Niklyaev V. S. (2000). Fundamentals of Agricultural Production Technology. Agriculture and Crop Production. Moscow: “Bylina”.
4. Rubatzky, Vincent E., Yamaguchi, Mas. (1997). World vegetables: principles, production, and nutritive values. 2nd ed.
