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(Fagopyrum), a genus of mostly annual, more rarely perennial, herbaceous plants of the buckwheat family (Polygonaceae). The stems are bare and branching; the leaves are alternate and sagittate-triangular; the flowers are monoecious, dimorphous, and heterostylous (having short styles with long stamens and long styles with short stamens). The perianth has five divisions; there are eight stamens alternating with nectaries, and a pistil with three styles and a trihedral ovary. The fruit is nutlike. The genus Fagopyrum comprises four or five (according to some data as many as 15) Eurasian species that grow in regions of temperate climate. Two wild species are found in the USSR: Tatar buckwheat (F. Tataricum) is a weed in most regions of the Soviet Union but is cultivated in Middle Asia as a source of vitamin P (rutin); semishrub buckwheat (F. suffruticosum) is a perennial endemic to Sakhalin. A cultivated species, buckwheat, or edible buckwheat (F. sagittatum or F. es-culentum), is sown.
Cultivated buckwheat is an annual plant 30–200 cm tall. The root is rodlike. The flowers range from white to red in color and have a pungent odor; they are gathered into a raceme, corymb, or dichasium. The weight of 1,000 fruits (nuts) is 20–30 g. The vegetative period is 60–120 days. The blossoming period is quite extensive—25–40 days. There is cross-pollination, carried out primarily by bees. The shoots of cultivated buckwheat appear at 7°-8°C and develop normally at an air temperature no lower than 12°-13°C; they perish in frosts from -2° to -3°C. Dry, hot weather (over 30°C), especially in the blossoming period, leads to incomplete fertilization, which diminishes the harvest considerably. Buckwheat is hydrophilous; its transpiration coefficient is 500–800; however, rains during the blossoming period disrupt the setting of the fruit. The best soils for buckwheat are chernozems and cultivated peat bogs. Sown buckwheat is cultivated in order to obtain the grain, which is processed to make groats and flour. Buckwheat proteins (10–13 percent of the seed) are more complete than cereal proteins. The byproducts of the processing of the seeds—husks, farina, straw, and chaff—are used for fodder. The ash of buckwheat yields potash, the leaves and flowers vitamin P. Buckwheat is a good nectar-bearer (up to 40–60 kg of nectar are obtained from one hectare [ha]).
Cultivated buckwheat originated in the mountainous regions of India and Nepal (Himalayas), where it was first grown more than 4,000 years ago. It was grown on the territory of the USSR in the first century A.D., and only in the 15th century did its cultivation spread to Europe. In 1970 the world planting area of buckwheat was 1,975,000 ha (predominantly in the USSR, Poland, Czechoslovakia, France, the German Democratic Republic, the Federal Republic of Germany, and Canada); the average yield of grain is 8.4 centners per ha. In the USSR in 1970, 1.88 million ha were planted with buckwheat. The gross harvest of grain was more than 1 million tons, with an average yield of 5.7 centners per ha, and on leading farms the yield was 20–35 centners. The principal regions of buckwheat cultivation in the USSR are the forest steppe of the Ukraine, Byelorussia, the central chernozem regions, Bashkiriia, Tatariia, the Urals region, and the Volga region. Regional varieties grown include Bogatyr’, Bol’shevik, Kalinin, and Shatilov 4.
Buckwheat is planted after legumes, sugar beets, potatoes, and other crops. The field is given a fall plowing, is harrowed in the spring, and is then cultivated two or three times with simultaneous harrowing. On turf-podzolic and gray pod-zolized soils, buckwheat needs more nitrogen and phosphorus fertilizers; on chernozems, it needs more phosphorus. Among the potassium fertilizers, ash or potassium sulfate are best for buckwheat. Buckwheat reacts favorably to the residual effect of manure or other organic fertilizers. It must be planted in adequately warmed soil. Planting times are selected so that blossoming does not coincide with very hot weather. The methods of sowing are compact-row (15 cm between rows) and wide-row (45–60 cm between rows); seeding rates are, respectively, 80–100 and 45–50 kg per ha. Seeds are placed 4–7 cm deep. Wide-row plantings require between-row cultivation. For the best pollination of buckwheat, apiaries are brought to the fields (one or two bee colonies per ha). When there is rusting of 70–75 percent of the grains, buckwheat is harvested by a separating method. Buckwheat is damaged by psyllas, aphids, and other pests; diseases include false mildew and gray mold.
REFERENCESStoletova, E. A. Grechikha. Moscow-Leningrad, 1958.
Kopel’kievskii, G. V. Kul’tura grechikhi. Moscow, 1960.
Krotov, A. S. Grechikha. Moscow-Leningrad, 1963.
Savitskii, K. A. Grechikha. Moscow, 1970.
G. V. KOPEL’KIEVSKII and M. E. KIRPICHNIKOV