Crops

Fagopyrum esculentum Moench. ssp. vulgare St. - Common buckwheat, cultivated buckwheat.

Taxonomic position.

Family: Polygonaceae Juss., genus: Fagopyrum Moench., species: Fagopyrum esculentum Moench. - S.K. Cherepanov, 1995

Synonyms:

Polygonum fagopyrum L., Polygonum cereale Salisb., Fagopyrum sagittatum Gilib., Fagopyrum fagopyrum Karsten, Fagopyrum emarginatum Roth.,Fagopyrum macropterum a. emarginatum Fenzl., Fagopyrum cereale Raf.

Biology and morphology.

2n=16. Annual herbaceous plant. Stem is 20 to 70 cm high or higher, ramified, ribbed, with internodes. Internodes are usually hollow, while nodes are filled with parenchyma. Internodes are bare. Nodes are sunken. Lateral branches give off alternately more rarely simultaneously from opposite sides. Stem is green, tinged with red. Stem internodes end in leaf-bearing nodes. Seed leaves are kidney-shaped and rounded with palmate nervation. Lower leaves are stalked. They are heart-shaped or somewhat arrow-shaped. Closer to the top of the shoot the stalks become shorter and the leaf-blades - less wide. Upper leaves are sessile and arrow-shaped. Leaves are alternate, entire, 1.7 to 6.5 cm long, with palmatifid nervation. Buckwheat flowers are dimorphic. They grow as spreading panicles in long axillary spikes with a strongly perfumed corymbose inflorescence on the top of the stem. Perianth has five lobes 3 to 5.5 mm long. It is a corolla pale-pink-, rarely pink-, very seldom red- or white-colored. It becomes pink at lower temperatures. Each flower has eight stamens. They grow in an alternate order with eight glands which secret honey-flavored nectar. Stamens grow in two circles. The inner circle is triandrous, and the outer circle is pentandrous. Pistil is triquetrous and trigonous. It has a one-cell superior ovary; stigmae have a porous surface. Common buckwheat is a dimorphous heterostylos plant. Buckwheat populations consist of two kinds of plants. The plants of the first kind have flowers with a long-columnar pistil and short stamens (long-columnar plants), while the plants of the second kind have a short-columnar pistil and long stamens (short-columnar plants). Plants of both kinds usually grow together in approximately equal numbers (1:1). Buckwheat fruit (achene) looks like a nut and is diamond-shaped or rounded. This single-seed fruit usually is three-sided in form and 5 to 7 mm long. Individual plants may have some nuts with a greater number of sides (up to 12). Fruit edges are smooth and usually are rather prominent. Fruit ribs are obtuse or sharp, straight, winged or wingless. Buckwheat nuts are brown, rarely gray or black tinged with violet. Their surface usually has a pattern of thin lines and dots. The usual color is typical of mature nuts. Nuts matured under unfavorable conditions and hollow ones are reddish-brown. Buckwheat fruit have two coats separate from the grain: a fruit coat and a seed coat. The seed coat covers the endosperm which makes up about 70 percent of the fruit weight. The germ with its two pale-green seed-lobes resides in the center of the fruit and is surrounded with a tight-fitting endosperm. Buckwheat germs have one rootlet which gradually grows into a thin spur which soon gives off lateral roots arranged in several tiers. These lateral roots give off their own lateral roots, etc. forming a thick mesh of thin roots running through the soil in every direction. Buckwheat is apt to form appendicular roots on the caulicle and on the stem and branches as well.

Ecology.

Buckwheat is a long-day, spring, hygrophilous cultivated plant. It is heat-loving (young plants being ruined by night and morning frosts of -2° C). Its vegetation period lasts for 60 to 120 days. It thrives on black and ameliorated peat soils. Buckwheat is a cross-pollinating entomophilous plant. Over 1 billion of flowers may blossom per hectare sown with buckwheat. Their number is several times greater than the number of wheat or barley flowers on the same area. When sown closely, buckwheat forms 400 to 500 flowers per plant, while spaced buckwheat plants have 3 to 5 times more flowers per plant. Main buckwheat self-protection and adaptation feature is its capability of prolonged healthy growth. When exposed to unfavorable environmental conditions, buckwheat redistributes the flow of assimilants to the growing organs of the maternal plant to the prejudice of the developing grains. While the fruit formation process with buckwheat is very sensitive to the deficit of warmth and moisture, this plant is in most cases highly enduring. Buckwheat fruit formation process readily reacts to changes in environmental conditions and is easily suppressed and recommenced.

Distribution.

Buckwheat has been cultivated since 3000 B.C. F. tataricum is the closest relative of cultivated buckwheat. Spring barley and wheat cultivated in the mountains are often infested with its high altitude variety - F. tataricum var. himalaica. It has not been proved that the cultivated buckwheat originated from this plant. Cultivated buckwheat is a native of the Himalayas. There are many various wild and cultivated buckwheat varieties in Nepal and India. There is no buckwheat in Mongolia. In Western Europe buckwheat has been cultivated since the 11th century. Before the Revolution of 1917, buckwheat was the only plant cultivated in some Russian provinces (e.g. in Chernigov province). Buckwheat was also cultivated much farther to the North even in Perm and Viatka provinces. Nowadays buckwheat is cultivated in moderately warm areas of the northern hemisphere. Ukrainian forest-steppes and marshy woodlands, the Central Black Earth Belt, the southern part of the Nonchernozem Belt, forest-steppes of the Volga region, the Urals, Western Siberia, some areas in Eastern Siberia and the Far East, Northern Kazakhstan and Belorus have the most favorable environmental conditions for buckwheat cultivation. They are a narrow belt of areas between 50 and 60°N latitude. In the North buckwheat cultivation is limited by the total of temperatures (above 13°C) of 1600 to 1800°C, in the South it is limited by high temperatures (above 22°C) and by inadequate rainfall during the fruit formation period. In all its main cultivation areas buckwheat typically blossoms and forms fruit in July and early in August when the average monthly rainfall is 50 to 70 mm, and the average day temperature is close to 17 to 18°C. In the Russian Federation buckwheat is widely sown in Altai Territory, in Bashkiria (now Bashkortostan), in Tatarstan, and in Ryazan, Orel, Tula, Orenburg, Kursk and Bryansk regions. Buckwheat is also widespread in Lipetsk, Saratov, Volgograd, Chelyabinsk, Chita, and Amur regions, in Stavropol, Krasnodar and Primorie Territories. In 2001 areas sown with buckwheat on all kinds of farms totaled 1594,000 hectares (or 3.4 percent of the total area sown with cereal crops). The State Register of Approved Breeding Achievements of 2004 mentions 44 buckwheat cultivars. Main varieties are: Aromat, Bogatyr, Demetra, Dikul, Kama, Kuybyshevskaya 85, Skorospelaya 86, Tatyana, Cheremshanka and others. Buckwheat breeding agencies are: All-Union Research Institute of leguminous and grain plants, Siberian Research Institute for plant cultivation and breeding of Russian Agricultural Academy, Tatar Research Institute for Agriculture, Bashkir Research Institute for Agriculture, Tulun State breeding station.

Economic value.

Buckwheat is a valuable grain and fodder cultivated plant. Unground buckwheat grains contain 12.6 percent protein. The bulk of the proteins (80 percent) belong to easily soluble albuminic and globulin fractions and therefore are readily assimilated by human body. Protein amino-acid composition is well-balanced. Buckwheat proteins contain many indispensable amino-acids including lysine and threonine while other grains and bread are deficient therein. Among amino-acids buckwheat proteins only lack in leucine while protein of other cereal crops abounds therein. Having a high content of such indispensable amino-acid as histidine, buckwheat grains have a positive influence on infantile growth. The biological value of buckwheat proteins (the amino-acid score) is close to that of dried milk proteins (92.3 percent) and hen's egg proteins (81.4 to 99.3 percent). Buckwheat carbohydrates are mainly starch (63.7 percent). Buckwheat also contains small quantities of cellulose (1.1 percent) and other saccharides. Buckwheat fats are nondrying oils. Their iodine and oxidative values are low. Their important feature is a high contents of linoleic and linolenic acids. Unground buckwheat contains much vitamin E, known for its antioxidative capabilities. Hence buckwheat grains can be stored for a long time without losing their edible quality which is important for setting up food stocks. Buckwheat is the only Russian grain plant containing rutin (vitamin R). Moreover, its niacin (vitamin RR), riboflavin and folic acid contents is greater than that of other grain plants. Buckwheat grains contain much iron, copper, cobalt, manganese, and other trace elements. Inferior grain and processing wastes are fed to poultry and pigs. Young cattle and pigs like eating buckwheat chaff. 1 kg of chaff contains 57 g of protein, its fodder value is equal to 0.5 fodder unit. Buckwheat quickly builds up green material (up to 20 tons per hectare in 50 to 60 days). It can be successfully cultivated toward this end on lands after haymaking and crop harvesting. Vegetative mass is fed as green fodder and used for ensilage. It usually is mixed with other components since buckwheat flowers and fruit shells contain fagopyrin, and this pigment causes in white livestock and white livestock with spots the so-called light or buckwheat disease. Husks possess no fodder value but can be used for stuffing pillows. While blossoming, buckwheat plant tips are used as raw material to obtain rutin (6 percent). The essence of buckwheat plants at the grain maturing stage is used in homoeopathy as a cure for eczema, rheumatism, etc. Buckwheat is a fine bee plant (70 to 100 kg of honey can be collected per hectare). Upon introduction of intensive agricultural technologies buckwheat can yield up to 259.8 kg of honey per hectare. Buckwheat honey is tinged with dark red or brown. It contains more iron and protein substances than other honeys. Alongside with correct agricultural technologies buckwheat sowing helps eliminate such persistent weeds as couch-grass, sow-thistle, and wild oats. Remainder of buckwheat roots and bits of plants left over after mowing contain much phosphorus and potassium. Hence buckwheat is a good precursor of spring and winter cereal crops. Buckwheat reacts well to nitrogenous fertilizers (30 to 45 kg per hectare). In the year 2000 buckwheat on the average yielded on farms of all kinds 690 kg of grains per hectare, and in the year 2001 - 540 kg of grains per hectare.

References:

Zhukovsky P. M. Cultivated Plants and Their Congeners. Leningrad: 1971.
Cultivated Flora of the USSR. Ed. Wulf E.V. Leningrad: 1941
Kargaltsev Y.V., Trutskov F.М. Bucjwheat. Moscow: 1986
Fesenko N.V. Buckwheat Breeding and Seed-Farming. Moscow: 1983

© Gashkova I.V.

Photo Lee Yu.S.