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(rye), a genus of annual and perennial herbaceous plants of the family Gramineae. The 13 species include 11 wild species, which grow in Asia Minor, Middle Asia, Iran, Afghanistan, Transcaucasia, and southern Africa; the weed S. segetale which infests wheat plantings in the mountain and foothill regions of the Caucasus, Asia Minor, and Middle Asia; and one cultivated species, S. cereale, which is raised mainly in the northern hemisphere and includes a number of varieties. There are spring and winter forms of cultivated rye; the latter is more widely cultivated.
The strong, fibrous root system of the rye plant is located in the upper layer of soil; only a few roots reach depths of 2 m. The stem, a hollow straw reaching an average height of 110–180 cm, consists of six or seven internodes. Lateral shoots may develop on the approximate underground nodes. The leaf consists of a sheath and a linear-lanceolate blade; the green or bluish green blade is mat or has a waxy bloom. The inflorescence is an awned compound spike, which is elongate-elliptic, prismatic, or spindle-shaped. At each node of the rachis there is one spikelet, in which are laid down five or six bisexual flowers, of which only two or three usually develop. Rye is a wind-pollinated plant. The fruit, a naked caryopsis called a grain, has a seed coma on the upper end. The oblong grain has tiny wrinkles and is green or gray (less commonly, brown or yellow) in color. One thousand seeds weigh 20–47 g.
The active vegetative stage of winter rye is 120 to 150 days long and is divided into two periods: autumn (45 to 50 days), when the vegetative organs develop, and spring-summer (75 to 100 days), when the plants form their generative organs and yield a harvest. The seeds sprout at temperatures of 1°-2°C, and shoots appear at temperatures of 4°-5°C. Normal spiking and flowering require a mean daily temperature of 14°-15°C.
The successful cultivation of winter rye depends on the plant’s winter-hardiness, especially its frost resistance, which is determined by conditions of autumn hardening off by varietal characteristics. Winter rye is relatively drought resistant, requiring the greatest amount of moisture during grain plumping. The plant can develop on all types of soils except marshy ones. The highest yields, however, are obtained on fertile, well-aerated chernozems. Rye requires the most nutrient matter during tillering and grain plumping. To form one quintal of grain the plant consumes 3.1 kg N, 1.4 kg P2O5, and 2.6 kg K2O.
Rye has several uses. The flour is used for bread, and the grain, bran, and green mass are used as livestock feed. The grain is also used in the production of mixed feeds and alcohol and in starch hydrolysis.
Cultivated rye is native to the foothill regions of the Caucasus, Asia Minor, and Middle Asia. It is descended from S. segetale, which grows as a weed in winter wheat and barley plantings. With the northern migration of wheat, rye, being hardier and less demanding in terms of growing conditions, crowded out wheat plantings and gradually became a crop plant itself. Rye cultivation originated in the first or second millennium B.C. in the basins of the Dnieper, Dnestr, and Oka rivers and in what is now Switzerland, Hungary, and Denmark. The first records of rye plantings in the Russian state are in chronicles of the 11th and 12th centuries. (See Table 1 for statistics on world rye production.)
The principal regions of rye cultivation in the USSR are the nonchernozem zone and the central chernozem region of the RSFSR, the Volga Region, the Urals, Siberia, Byelorussia, the Poles’e of the Ukraine, the Baltic republics, and Kazakhstan. The best varieties are Viatka, Viatka 2, Kazan, Beniakon, Kharkov 60, and Omka. The best new varieties include Hybrid 2, Belta, and Nemchinovskaia 50. In 1974, 53 varieties of winter rye were regionalized.
Rye is sown in rotation on true or occupied fallows after barley, clover, and other crops. During deep autumn plowing 40–60 tons/hectare (ha) of manure and compost and 60–80 kg/ha of NPK are applied. When sowing in rows 7.5–10 kg/ha P2O5 is applied, and for spring feeding 20–30 kg/ha N is used. Rye is planted in rows 7–8 cm apart or 15 cm apart. The rate of seeding is 4.5–6 million viable seeds per ha; the sowing depth is 2–6 cm. Snow retention is important, and in the spring the plantings are harrowed. Herbicides are used (2.4-D, 2M-4X). Rye is gathered by swathing or by direct combining.
Insect pests include the frit fly, Hessian fly, Hylemia coarctata, and Eurygaster integiceps. Diseases include ergot, smut, snow mold, and sclerotiniose.
Spring rye is less demanding as to growing conditions than winter rye. It is cultivated on small areas in the same countries as winter rye; in the USSR it is grown in the Yakut ASSR and the Buriat ASSR (variety Onokhoiskaia 2).
The commercial cultivation of spring rye involves almost all the same procedures as the raising of oats or spring barley.
|Table 1. World rye production|
|Sown area (million ha)||Gross grain harvest (million tons)||Yield (quintals per ha)|
|1 Very little rye is cultivated in Africa and Australia 2ln the USSR the greatest average yields in 1973 were obtained in Estonia (24.6 quintals/ha), Byelorussia (23.0 quintals/ha), and Lithuania (21.5 quintals/ha)|
|Source: UN Food and Agriculture Organization, 1972|
|Federal Republic of Germany...............||1.18||1.13||0.86||0.84||2.51||2.82||2.66||2.91||21.2||25.0||30.8||34.6|
|German Democratic Republic..........||0.82||0.82||0.68||0.66||1.50||1.91||1.48||1.9||18.2||23.2||21.8||28.6|
REFERENCESTiunov, A. N., K. A. Glukhikh, and O. A. Khor’kova. Ozimaia rozh’ Moscow, 1969.
Zhukovskii, P. M. Kul’turnye rasteniia i ikh sorodichi, 3rd ed. Leningrad, 1971.
Rozh’ Moscow, 1972.
O. A. KHOR’KOVA