Crops

Beta vulgaris L. ssp. vulgaris convar. saccharifera Alef. - Sugar beet.

Synonyms:

Beta vulgaris L. ssp. vulgaris var. altissima Doell.

Taxonomic position.

Family: Chenopodiaceae Vent., genus Beta Tourn.(L.), species Beta vulgaris L.
V.T. Krasochkin proposed a more convenient classification of beet with edible roots (1971). He distinguishes two subspecies: European - subsp. europea Krassochk. and Asiatic - subsp. asiatica Krassochk. Within the European subspecies he distinguishes three groups of varieties: convar. esculenta (table beet) Salisb., convar. crassa Alef. (mangel) and convar. saccharifera Alef. (sugar beet); the latter includes two varieties: var. saccharifera Alef. and var. grisea Zoss.

Biology and morphology.

2n=18. Sugar beet is a biennial cultured plant. Its root is thickened, white-colored and edible. It is conical or elongated conical in shape. Its surface is rough. It is often branched and difficult to extract from the ground. Its pulp is white and thick. It has 3 to 5 cambium rings and numerous conducting bundles. It is sugary and has a high content of solids (24 to 26 %) and sugar (17 to 19 %). However, its monosaccaride, acid and limy elements' content is low. Sugar beet leaf rosette has 20 to 30 leaves whose lamellae are dark-green and wavy; the petiole is green. Sugar beet stalk is herbaceous, upright, and highly ramose. It emerges on the 2nd year of the plant's life. By the time the seeds ripen, the stalk lignifies. Sugar beet leaves are fleshy, alternate, entire, smooth or wavy, three-cornered. Radical leaves have long petioles, while cauline leaves are small, almost sessile and lanceolate. Sugar beet flowers are bisexual, pentamerous with or without three bracts. These flowers are small, green or whitish in color, single or in groups of 2 to 5 or more. Later they form seed balls and are united into very long leafy inflorescences (ears). The bract is linear-lanceolate. It is longer than any of the seed balls. The perianth is calycine, pentamerous. At its base it is concrescent with the gynaceum. The perianth hardens when the fruits mature. There are 5 stamens on a fleshy disk around the gynaceum. The anther filaments are as long as perianth lobes or shorter. The gynaceum is partly inferior. On the fruits it is covered with withered and suberified remainders of the perianth. The gynaceum is almost three-cornered in cross-section and flattened on top. The stigma has 2 to 3 lobes. It is almost sessile. The ovule is located by the gynaceum wall on a short funicle. Since the gynaceum is concrescent with the perianth, the fruit has a fleshy pericarp with a cap. This pericarp gradually hardens. Sugar beet seeds are horizontal, flattened, glabrous with a rostellum. Sugar beet embryo is annular and irregular. The fruits collected into seed balls are rather small, yellow, brownish-yellow or brownish in color. When mature they are readily shredded. Each seed ball contains 2 to 8, more often 3 to 4 seeds. There are sugar beet varieties with one seed per seed ball. 1000 seed balls weigh from 18 to 30 to 32 to 50 g; 1000 seeds weigh from 1.5 to 2.0 to 5 to 6 g.

Ecology.

During the first year of their life sugar beet plants form their edible roots and leaf rosettes. Sugar beet is quite a heat-loving, light-requiring, and hygrophilous plant. It is salt-tolerant and quite drought-resistant. Sugar beet seeds prefer to germinate at 10 to 12° C. The plant grows and develops well at 18 to 22° C. Young shoots are damaged by night and morning frosts of -3, -4° C. Leaves of adult plants resist short morning frosts of -5, -6° C. On the other hand, dug up and uncovered sugar beet roots are damaged by the temperature of -2° C. In the main sugar beet cultivation areas the total of temperatures varies within 2500-3000° C. Lower temperatures in the North may be compensated by good nourishment and progressive cultivation techniques. Higher temperatures in the South may be compensated by lavish watering. Sugar beet is especially demanding to the moisture content of the soil while its seeds germinate and the sprouts strike roots. The same is true about the period of maximum leaf surface development. In order to accumulate 100 kg of solid matter sugar beet plants must evaporate 300 to 400 kg of water (such is their transpiration ratio). Due to elevated air humidity in the North, in those areas this ratio is equal to 200 to 250 units. About 3000 to 4000 м³ of water per hectare are needed to form 4 000 kg of sugar beet edible roots. Sugar beet is on the whole more drought-resistant than chards, mangel and table beet. Sugar beet thrives on loamy soils and loamy sands rich in organic substances and especially on black earth. It may grow well enough on clay soils if they are fertilized with manure, mineral fertilizers and lime. Soils should preferably contain up to 15 % clay since it retains and absorbs water well. In the Non-Chernozem Belt sugar beet is often grown on podzolic shallow arable soils. Such soils should be limed. They need elevated amounts of organic fertilizers. Their subsoil should be loosened in order to increase the topsoil. The optimal soil acidity varies around pH 6.0 to 7.0. If it is higher (pH 5.0), the sprouts suffer from Pythium disease, grow more slowly and their leaves become tinged with anthocyan. Growing on saline soils, sugar beet yields less, and its edible roots contain less sugar. However, in such cases they contain more ashy elements. An elevated ash content decreases the value of beet roots as a source of raw material for sugar refining but increases their value as fodder. At first the ability of sugar beet roots to accumulate 2 to 3 times more sugar than mangel roots was explained by a higher photosynthetic ability of sugar beet leaves. However grafting of sugar beet leaves on mangel roots and vice versa (Okanenko A.S., 1940, 1968) revealed that the features of the edible root structure are much more important. In fact, mangel leaves' ability to synthesize sugars is almost as high as that of sugar beet leaves. But the sugars synthesized by mangel leaves are more readily used up in respiration and growth processes. Longer daylight in the North mainly accelerates generative development. Sugar accumulation in the northern latitudes is mostly influenced by the temperatures and by the prolonged life of adult leaves rather than by the length of daylight. Considerably lower night temperatures favor outflow of sugars to edible roots and, which is still more important, decrease the amount of sugars used up in respiratory processes as compared to warmer nights in the South. Since the leaves are moistened more and less afflicted with diseases in the North, their life there is much longer. Even at the time of harvesting the leaf rosettes are as green as usual, viable and weigh more than roots. In the South adult leaves die off by this time. The vegetation period of sugar beet lasts 180 to 200 days. Flowering is initiated in the second growing season after a prolonged period of cold weather (vernalization), with temperatures below 10°C for 30 to 60 days. The first to blossom are the lower flowers of the main stalk. Gradually the flowers on the lateral shoots begin to blossom as well. Therefore each plant blossoms for a long time. In the South sugar beet plants on plantations usually blossom for 10 to 15 days, in the North up to 40 to 50 days. Individual flowers blossom for 5 to 7 sometimes for 8 hours. About 66 % flowers open up early in the morning (before 8 o'clock, only 14 % open up at 8 or 9 o'clock. In the South sugar beet plants blossom a little more actively between 7 and 6 o'clock p.m.. 30 to 80 minutes after the flower opens up, the anthers begin to pollinate. Pollination lasts for 3 to 4 hours and is over on the same day. Late in the afternoon the anthers become partially brownish, and on the following day they fall off. The period from the first blossom to the formation of new seeds lasts for 24 to 26 days. The pollen is transported among the plants mostly by the wind, sometimes by insects (plant-lice, ants, etc.). Table beet, mangel, sugar beet, chard beet and related varieties of beet easily interbreed.

Distribution.

The man began to consume wild beet in the time immemorial. The Mediterranean peoples began to cultivate chard beet in the 1st or 2nd millennia B.C. Some cultivated varieties of common beet with edible roots had appeared by the beginning of the Common Era. In the 10th and 11th centuries they were already known in Kievan Rus. In the 16th and 17th centuries Russians already knew table and fodder varieties of beet; in the 18th century sugar beet was singled out among various hybrids of mangel. Sugar beet has been cultivated on all the continents since the late 19th and early 20th centuries. At present sugar beet is cultivated in the Central Black Earth Belt of the Russian Federation and in such former republics of the Soviet Union as the Ukraine, Kazakhstan, Kirghizia, Moldova. Sugar beet as raw material for industrial-scale extraction of sucrose is one of the most recent cultured plants. In the Middle Ages it grew in gardens and vegetable gardens. It was in vegetable gardens that shard and root varieties of beet were interbreeding. Later their hybrid populations were subjected to artificial selection. Early in the 19th century Marggraf's pupil Achard began to select sugary varieties among Silesian hybrid populations. However it was in the mid 19th century that L. Vilmorin began to breed sugar beet along strictly scientific lines. He interbred the Imperial Knauer sugar variety with chard beet having a powerful radical leaf rosette. He pollinated the first generation with the pollen of beet with edible roots. In other words, he used backcrossing. Thus originated the progeny evaluation breeding technique. Sucrose was found in edible sugar beet roots, and the German chemist Marggraf established its identity with that in the sugar cane stalk. The first sugar-refinery was built in Cunern (Lower Silesia) in 1802. Napoleon issued a decree that established several sugar-refineries in France. The first sugar-refinery in Russia was built in 1801 in Alyabyevo - a village in Tula province. Gradually sugar beet cultivation moved to the Right Bank in the Ukraine. The first sugar appeared in the market in 1850. In the 1860s beet sugar began to prevail over cane sugar since the sugar cane was everywhere subject to epiphytoties, and its varieties were then unstable. As soon as stable sugar cane varieties were bred, cane sugar refining prevailed again and its volume amounted to 3 times that of beet sugar refining.
Sucrose content in sugar beet roots was being gradually increased by breeding new varieties (however in 10 years' time the sucrose content was on the average increased by only 0.1 % by way of artificial selection). Tetraploid varieties 2n = 36 were a disappointment. Triploid varieteis 2n = 27 did not seem economically feasible. The use of tetraploid lines of breeding with sterile pollen allowed to obtain almost 100 % triploid seeds.
Sugar beet varieties with one seed per seed ball were first bred in the USSR and now are widespread. They are: North Caucasian single seed 42, L'govskaya single seed 52, Biyskaya single seed 50, Ramonskaya single seed 47, Ramonskaya single seed 99, Uladovskaya single seed 35, etc. By now 5 cultivars and 123 hybrids of sugar beet have been approved for cultivation in certain regions of the Russian Federation. Main breeding agencies are: North Caucasian Research Institute for sugar beet and sugar, All-Union A.L. Mazlumov Research Institute for sugar beet and sugar, L'gov experimental breeding station, Biysk experimental breeding station. German and Swedish hybrids are most prominent among those bred abroad (Aura, Gratsia, Lauretsia, Lena, Sonya, etc. - German; Inger, Cremona, Swea, Hilma, Eureca, etc. - Swedish).

Economic value.

Sugar beet edible roots contain up to 24 % sucrose and are raw material for sugar refinery; production wastage is used as livestock fodder (molasses, bagasse) and fertilizers (press cakes). In crops rotation sugar beet follows winter wheat sown after perennial herbs on bare and full fallow lands. Approximate fertilizer application rates are: 20,000 to 30,000 kg of manure or compost per hectare; among mineral fertilizers - 30 to 60 kg of N per hectare, 30 to 90 kg of P₂O₅ per hectare and 45 to 60 kg of K₂O per hectare. Fertilizing drills while sowing and additional fertilizing are very efficient. Sugar beet seeds are sown in wide-row drills or in a single-grain way. In the former case 15 to 28 kg of seeds are sown per hectare, in the latter case 10 to 15 kg. Planting depth is 2 to 5 cm. Coated seeds also yield good results. Care of crops: harrowing before and after sprouting, blocking, block thinning, tillage, additional fertilizing and watering. Sugar beet is harvested as soon as it accumulates the greatest amount of sugar in its roots mostly with beet harvesters. Beets can be lifted mechanically using the tops. Good top development is encouraged in beets harvested by this method. In the other method, a flail removes the tops prior to harvest. The beets are then harvested from the soil like potatoes. Introduction of single seed varieties allows to use intensive cultivation techniques without manual labor. The average sugar beet yield is 2.400 kg per hectare, the highest possible yield is 35.000 to 40.000 kg per hectare.

References.

Burenin V. I., Adighezalov I.I., Vasilyev Y.V. Industrial Sugar Beet Technology. Moscow: 1983
Burenin V. I., Pivovarov V.F. Beet. St. Petersburg: 1998
State Register of Breeding Achievements Approved for Practical Application in the Russian Federation in 2004. Moscow: 2004, p.56-58
Zhukovsky P.M. Cultivated Plants and Their Congeners. Leningrad: 1971
Krasochkin V.T., Sechkarev B.I., Sazonova L.V., Levandovskaya L.I. Cultured Flora of the USSR. Root Vegetables. Vol.19. Leningrad: 1971, p.7-266
Manual for Approbation of Vegetables and Forage Root Vegetables. Ed. Brezhnev D.D. Moscow: 1982, p.277-315
Petrov V.A., Borzakovsky I.V. Beet Grower's Manual, 2nd edition. Moscow: 1985

© Gashkova I.V.