Changes

*Rye (En). *Seigle (Fr)

Rye is known only from cultivation. The gene centre of rye is located in the mountainous areas of Afghanistan, Iran and the Middle East, from which other small-grain crops like wheat, barley and oats also originated. From there, rye was spread to the surrounding areas in Asia (Iraq, Turkey), northern Africa and later, just like wheat, to Russia, Central and West Europe, where it is cultivated under temperate climatic conditions. Due to its hardiness to drought and frost, rye was spread well beyond 60N60 °N. It has been spread to all continents, especially to areas with temperate growing conditions. Occasionally it is cultivated at high elevations in the tropics and subtropics, e.g. in East and South Africa.

*Annual (spring rye) or biennial (winter rye) tufted herb, 1-1.5(-3) m tall, often blueish-green in colour. Root system extensive, penetrating to 1-2 m depth. *Culm erect, slender, glabrous except pubescent near the spike, with 6-7 (spring rye) and 10-12 (winter rye) nodes of which the 5-6 basal ones are very close, with hollow internodes; one leaf is produced at each node, the basic nodes also producing shoots or tillers and crown roots. *Leaf sheath long and loose; ligule short, jagged; auricles short and small; blade linear-lanceolate, 10-20 cm × 1-2 cm, smooth or slightly scabrous. *Inflorescence a terminal spike, 7-15 cm long, curved, much awned, narrow but close-flowered; spikelet .*Spikelet with 2 fertile florets, alternating on a long zigzag rachis; glumes subulate, 1-veined, up to 1 cm long; lemma up to 18 mm long, narrow, tapering into a 2-8 cm long awn, 3(-5)-veined, keel prominently set with stiff teeth; palea scabrid on the keel; stamens 3, pistil 1 with 2 plumose stigmas. *Caryopsis oblongoid, 5-9 mm long, light brown, narrowly grooved, short-pointed, glabrous.

Triticale ( ''Triticosecale'' Wittmack) is a cereal derived from hybridization of rye and wheat. After several cycles of selection, the resulting triticale cultivars show characteristics in between wheat and rye. Breeders strive to combine the hardiness of rye with the high yield and quality of wheat. Tetraploid (2 ''n'' = 28), hexaploid (2 ''n'' = 42) and octoploid (2 ''n'' = 56) forms exist, but the hexaploid forms are most successful. As a new food crop, triticale fell short of expectations, but it is becoming increasingly popular as a forage crop. Only where wheat does not grow well because of adverse conditions, triticale is a promising human food crop. It is estimated that it is grown annually on 1.5 million ha with Poland, France, Russia and Australia as the main producers.

Rye is the most tolerant among the small-grain cereals of variations in (low) temperature, water supply and soil type. It germinates at a soil temperature of 4-5°C 5 °C within 4 days and the seedlings can endure frost during winter down to -25°C25 °C. Vernalization occurs naturally. Tillering, shoot growth and flower initiation require rather low temperatures (10-15°C15 °C); for adequate growth during reproductive development the mean daily temperature must not exceed 20°C20 °C. The demand for water is relatively low; rye is more tolerant of water stress than other small-grain cereals. Flowering is favoured by dry and sunny weather. Continuous rain, high humidity and low temperatures hamper pollination, causing incomplete grain set. Rye is a cross-pollinated crop, depending on wind for the spread of pollen. It is suited for growth under temperate and continental climatic conditions. Winter rye is a long-day plant; the reproductive development is stimulated by daylength increasing from 14 to 20 hours. Therefore, winter rye is mainly grown between 40-65N. Cultivars of spring rye are occasionally grown at high elevations in subtropical and tropical areas. They are less sensitive to long daylength and do not need vernalization. Their flowering and seedset are satisfactory at a daylength of 12-13 hours.

Rye is considered to be a relatively tolerant cereal. Nevertheless, after germination snow mould ( ''Fusarium nivale'' ) can cause considerable plant losses and brown rust ( ''Puccinia recondita'' ) can severely damage leaves and stem. But the most conspicuous disease is ergot ( ''Claviceps purpurea'' ), which infects the kernel especially when grain set is poor. Ergot kernels are toxic and can make a rye stock unsuitable for human and animal consumption. Other diseases are e.g. eyespot ( ''Pseudocercosporella herpotrichoides'' ), sharp eyespot ( ''Rhizoctonia solani'' ), powdery mildew ( ''Erysiphe graminis'' ), stem rust ( ''Puccinia graminis'' ), glume blotch ( ''Septoria nodorum'' ) and leaf blotch ( ''Rynchosporium secalis'' ). Most fungal diseases can be controlled by fungicides, but damage by snow mould, sharp eyespot and ergot can only be restricted by using healthy and disinfected seed.

*A. Darwinkel