Chenopodium L. (grain chenopod)
- Protologue: Sp. pl.: 218 (1753); Gen. pl. ed. 5: 103 (1754).
- Family: Chenopodiaceae
- Chromosome number: x= 9; 2n= 36 (C. quinoa); 2n= 54 (C. album)
Major species and synonyms
- Chenopodium album L., Sp. pl.: 219 (1753), synonyms: C. candicans Lamk (1778), C. hybridum Lour. (1790), C. leiospermum DC. (1805).
- Chenopodium quinoa Willd., Sp. pl. 1: 1301 (1799), synonyms: C. guinoa Krocker (1823), C. leucospermum Schrader (1834), C. album L. subsp. quinoa (Willd.) Kuntze (1891).
General: Grain chenopod (En)
- Chénopode farineuse, ansérine (Fr)
- Vietnam: rau muối.
- Fat hen, white goosefoot, pigweed (En)
- Lamb's quarter (Am)
- Ansérine blanche, chénopode blanc (Fr)
- Cenizo (Sp)
- Indonesia: dieng, dieng abang, dieng putih
- Cambodia: momiënh
- Laos: hôm küa
- Vietnam: rau muối trắng.
- Quinoa, Peruvian rice, Inca rice (En)
- Quinoa, riz du Pérou (Fr)
- Quinua, arroz del Peru, trigo inca (Sp).
Origin and geographic distribution
Chenopodium is a large genus (100-150 species) found in temperate zones throughout the world. Some species have naturalized in the mountainous districts of the tropics.
- C. album: There is considerable evidence that in prehistoric times seed of fat hen was harvested for human consumption in both the Old and the New World. It is now mainly known as a noxious weed with global distribution, occurring from 70 °N to 50 °S. Fat hen has been domesticated in the Himalayan region, where it is grown in Nepal and northern India. It is also cultivated in the hilly regions of northern Thailand and in some mountainous areas of Java (Tengger), Indonesia.
- C. quinoa: Quinoa was probably domesticated between 3000 and 5000 years ago in several regions of the Andes, including Argentina, Bolivia, Chile, Colombia, Ecuador and Peru, and in the coastal regions of Chile. The crop was widely cultivated during the time of the Incas. After the Spanish conquest, there was a marked decline in the cultivation and use of quinoa. The traditional growing area in South America is between 2 °N latitude in Colombia and 40 °S latitude in Chile.
C. album is nowadays a subsistence food crop for isolated hill communities inhabiting the montane zone of the middle Himalayan range. Grains are used as pseudo-cereal and young shoots and leaves as a vegetable. The use as a vegetable has been reported from all continents, including South-East Asia (Java, Indonesia).
Fat hen seed is processed into flour for pancakes and bread, or is boiled and mixed with other ingredients to make a kind of gruel, or is roasted and ground for porridge, and used for preparing fermented and alcoholic beverages. The seed is also used for poultry and livestock feed.
C. quinoa grains are traditionally toasted or ground into flour. They can also be boiled, added to soups, or made into breakfast foods or pastas. When boiled like rice, the grains have a nutlike flavour, and remain separated, fluffy, and chewy. Quinoa has demonstrated value as a partial wheat-flour substitute for enriching unleavened bread. The plant is sometimes grown as a green vegetable, and its leaves are eaten fresh or cooked. The leaves and stalks can also be used for animal feed.
Production and international trade
Cultivation and use of C. album as a subsistence seed crop is limited to an estimated acreage of 1500 ha in the Himalayas.
An area of about 100 000 ha of C. quinoa is grown in the Andean countries. In the United States, an increasing demand for quinoa arose in 1980s and seed sales increased to 300 t in 1988. The seeds were mainly imported from South America. Grains, flour or pasta are now available in health food stores and supermarkets in North America and western Europe. In Colorado (United States), efforts were made to get the crop established at high altitudes and the first commercial crop was grown in 1988. In the United Kingdom, an application was found as a cover crop for game birds.
Although little information is available on cultivars of C. album, it is assumed that the qualities of the seed do not deviate remarkably from those of quinoa. Seed of the weedy types, however, might be of inferior quality. Seed is about 1.0-1.8 mm in diameter. 1000-seed weight is about 1.4 g.
Quinoa seeds are very small, and vary in diameter from 1.8-2.6 mm. 1000-seed weight ranges from 2-6 g. Quinoa seed has an exceptionally high nutritional value. The energy value is 1450 kJ/100 g edible portion. The embryo takes up a greater proportion of the seed than in common cereals, resulting in an average protein content of 16%. The protein is high in the essential amino acids lysine, methionine, and cystine, making it complementary to true cereals for lysine, and to pulses for methionine and cystine. The seed contains about 60% starch and 5% sugar. The starch granules are extremely small. The small size of 2-4μm gives the starch a fatty taste, and because of this property the starch can replace fat in diet products. The granules contain up to 20% amylose, and gelatinize in the 55-65 °C range. The lipid content is 5%, half of which is linoleic acid. The seed contains 4% cellulose and fibre and 3% ash. The pericarp of quinoa seed contains saponins, soaplike components which foam when dissolved in water. Saponins reduce palatability due to their bitterness, and are toxic if they reach the bloodstream, since they damage the membranes of red blood cells. They are usually removed from the grain by vigorous washing and rubbing or by removing the whole pericarp. The content of saponins varies from almost zero in saponin-free cultivars to 4% in bitter cultivars.
- Annual or rarely perennial herbs, sometimes with a pungent smell; young parts often densely to very densely clothed with minute, powdery, white or pink vesicles, usually soon losing their colour.
- Leaves alternate, petioled, herbaceous, variable in shape, entire, dentate-serrate or irregularly gashed.
- Inflorescence consisting of flower clusters, the clusters appearing solitary in leaf axils or arranged in axillary and terminal cymes, spikes or panicles; flowers hermaphrodite or female by abortion, sessile; bracteoles absent; tepals 2-5, free or shortly connate; stamens 1-5; pistil with depressed globose ovary, short style and 2(-5) stigmas.
- Fruit an utricle, often embraced by conniving tepals, thin-walled, indehiscent.
- Seed shiny or dull, smooth or finely tuberculate, lenticular; margin sometimes keeled; testa thinly coriaceous; embryo annular, surrounding the endosperm.
- Erect annual herb, 0.15-1.50(-3.80) m tall, not particularly pungent; young vegetative parts and outside of perianth densely clothed with mealy-white or red-purple vesicles, losing their colour sooner or later.
- Stem angular, ribbed, with longitudal dark green or red streaks.
- Lower leaves with long petioles, ovate-rhomboid, irregularly and coarsely dentate-serrate-laciniate or deeply gashed, higher ones gradually with shorter petioles, elliptical-oblong-lanceolate, less deeply incised or entire, 1.5-18 cm × 0.5-18 cm.
- Inflorescence large, axillary and terminal, leafy, paniculate, consisting of panicled clusters of flowers; flowers hermaphrodite; tepals distinctly connate at the base; stigmas 2.
- Fruit entirely enclosed by the incurved tepals.
- Seed nearly smooth, blackish-brown, 1-1.8 mm in diameter.
The cultivars can be distinguished from wild plants by their usually taller habit (up to 3.8 m), a large, leafless, exserted, compact and drooping inflorescence with bisexual and female flowers, 5 tepals, usually 5 stamens, non-shattering seed which is larger and predominantly black, brown or red.
- Erect, annual herb, 0.7-3.0 m tall.
- Stem round at the base, becoming more angular where leaves and branches emerge, green, yellow, red, purple or orange, or green with stripes of another colour. At maturity the colour may change to pale yellow or to red. The reddish colours are due to betacyanins, not anthocyanins.
- Leaves alternate, with long petioles, the lower ones tend to be rhomboidal and the upper ones lanceolate; leaves of young plants are green under their layer of pubescence, but turning yellow, red, or purple as the plant matures.
- Inflorescence a panicle, having a principal axis from which secondary axes originate, compact or lax, 15-70 cm long; in the "amaranthiform" type, clusters of flowers are directly inserted in the secondary axes, whereas in the "glomerulate" type the clusters of flowers are inserted in tertiary axes originating from the secondary axes; flowers incomplete (as no petals are present), hermaphrodite; tepals 5, anthers 5, superior ovary with 2 stigmatic branches.
- Fruit sometimes covered by the perianth, which can easily be removed by rubbing; pericarp translucent, white, yellow, orange, pink, red, brown or black.
- Seed translucent, white, brown or black.
Growth and development
Seedlings will emerge in approximately one week in a sufficiently moist soil with an average temperature above 10 °C. One week later the first true leaves will appear, and flowering may start 50-70 days after emergence. The period between sowing and anthesis and from anthesis until maturity is very variable. Early and daylength-neutral cultivars may take 50-60 days to flowering and 90-110 days to maturity, whereas late and short-day cultivars need 4-5 weeks longer. Grain chenopods are predominantly self-pollinating, cross pollination is less than 10%.
Other botanical information
The C. album which occurs wild worldwide is part of a very variable polyploid weed complex that has so many names (from species and subspecies to forma level) that it is impossible to describe and fix its polymorphy. In the montane zone of the central Himalayan region, forms selected from this complex are now cultivated for their grains and for their leaves. In Himachal Pradesh (India, northwestern Himalayas), four chenopod grain cultivars are distinguished mainly based on seed colour: "Black", "Brown", "Red" and "Earthen". The cultivars Black, Brown and Red certainly developed from the C. album complex and are quite similar in all characteristics except the predominant seed colour. "Earthen" however, is a deviating cultivar, and as well as having earth-coloured seeds the plants are smaller, the branching pattern is narrow-angled, the leaf type cordate or linear, and the seeds smaller (1000-seed weight is 0.8 g). "Earthen" has not developed from the C. album complex; it is closer to C. quinoa but too different from it to suppose evolutionary relationship. Its taxonomic position is still unclear.
The cultivated grain chenopod of Java (perhaps more important as a leaf vegetable) is quite similar to C. album, but distinguishable from it by its usually larger size (up to 2.5 m tall) and larger leaves (rhombic-deltate, up to 14 cm × 14 cm) but especially by its bright reddish-purple young parts (colour disappearing in older parts). It has been classified as C. album L. subsp. amaranticolor Coste & Reyn., but at present most authors consider it to belong to a different species in the C. album complex: C. giganteum D. Don, which also occurs worldwide.
Several cultivars adapted to local growing conditions have been developed in the production centres of C. quinoa in South America. Sea-level cultivars from Chile showed the best adaptation to western European conditions because of their daylength-neutral nature. In the United Kingdom, Denmark and the Netherlands improved cultivars have been selected from Chilean landraces and from the progenies of hybrids.
Two other grain chenopods are cultivated on a small scale in tropical America. The first one is C. berlandieri Moq. subsp. nuttalliae (Safford) Wilson & Heiser (2n= 36), synonym: C. nuttalliae Safford. This "huauzontle" occurs in Mexico, but its cultivation is declining. It is more important as a vegetable than as a grain crop. The second one is C. pallidicaule Aellen (2n' = 18). "Canihua" originated from the Andes and is important as a seed crop on the high plateau of Peru and Bolivia at altitudes between 3800-4300 m, where it can survive severe night frost of -10 °C. It is a small, 20-60 cm tall, much branched, bushy plant with a shorter growing season than quinoa. Contrary to quinoa, canihua seeds do not contain saponins. They are smaller and coloured brown to dark brown. Flowers appear to be virtually cleistogamous.
C. album is cultivated in Himalayan valleys between 1500-3000 m altitude, but its wide distribution as a weed points to tolerance of climates with average temperatures ranging from 5-30 °C. It tolerates night frost. In Java, it has naturalized at altitudes between 800-2300 m. In the long days of the temperate zone it grows to a large size and it is there that it offers the most serious competition to crops as a weed.
C. quinoa is a temperate or subtropical plant grown in areas with temperatures up to 35 °C. Higher temperatures may cause sterility. Quinoa withstands light night frost but is sensitive to temperatures below -3°C. The upper limit of cultivation is 4000 m altitude. Some cultivars are insensitive to photoperiod, whereas others flower later under increasing daylength. In South America, quinoa is grown under marginal conditions where other cereals cannot easily be cultivated. It grows best when rainfall is well-distributed during early growth and conditions are dry during maturation and harvest. It can withstand excessive amounts of rainfall during early growth and development, except directly after sowing. Wet conditions during germination can reduce emergence when the soil is poorly drained. Quinoa is notable for its drought tolerance, especially during late growth and maturation. At the end of the ripening period the crop becomes very sensitive to rainfall, and if considerable rainfall falls during one day the seed, which is not dormant, may sprout prematurely. Early cultivars are more sensitive for sprouting than late ones.
Quinoa is grown in soils varying in acidity from pH 6-8.5. It tolerates soils that are infertile, moderately saline and have low base-saturation. Although adapted to poor growing conditions, quinoa responds extraordinarily well to fertilizer.
Propagation and planting
The most common practice for grain chenopods is sowing 1-2 cm deep in rows 25-50 cm apart depending on the soil moisture content. Seed rate is 6-10 kg/ha, resulting in 100-150 plants per m2. The seed-bed should be well prepared. The seed may also be broadcast, but when sown in rows it is easier to weed. Broadcasting requires about 20 kg of seed per ha. In Himachal Pradesh (India), C. album is often intercropped, e.g. with finger millet, potato, maize, rice, amaranth, foxtail millet, sesame, soya bean, taro, cowpea or common bean.
Grain chenopods fit very well in crop rotations with other annual crops, e.g. Irish potato. Because of their well-developed rooting system, they can utilize nutrients left from the preceding crop, in particular phosphorus. In general, fertilization comparable to wheat or maize is recommended.
The most troublesome weed in quinoa cultivation is the related species C. album (fat hen). Fat hen has an almost identical habit and growing pattern to quinoa. The seeds of weedy fat hen are inferior in quality, and reduce the value of the harvested product. Therefore, land severely infested with fat hen should be avoided for cultivation of quinoa.
Diseases and pests
Grain chenopods are rather susceptible to damage by diseases and pests. The most important disease is downy mildew (Peronospora farinosa f.sp. chenopodii), which causes much damage in growing areas all over the world. The disease is favoured by warm and humid weather. Some cultivars are partially resistant. Other fungal diseases are leaf spot (Ascochyta hyalospora), brown stalk rot (Phoma exigua), grey mould (Botrytis cinerea), and seed rot or damping-off (Sclerotium rolfsii). A virus disease is known as chlorotic mosaic.
Several cutworm species attack the young plants. The most serious insect pest is a leaf miner or leaf sticker, Eurisaca melanocompta. Lyriomiza brasiliensis is another leaf miner found on grain chenopods. Caterpillars (e.g. Hymenia recurvalis) destroy leaves and inflorescences. Several loopers, beetles, aphids, leafhoppers and thrips may also cause damage. Chemical pesticides are often applied. In temperate countries, insecticides are used to control aphids and caterpillars.
Birds attacking the crop before harvesting or during field drying probably cause the greatest crop losses. Bitter cultivars are less prone to such attacks than sweet ones.
The crop matures in 4-5 months. It can be harvested after the leaves have senesced, when the panicle and the upper part of the stem have lost their specific colour. The harvesting methods commonly used for cereals can also be used for grain chenopods. Plants are cut, bundled and dried, threshed, and the grain is winnowed.
For fat hen, yields of 0.2-0.6 t/ha are reported from farmers' fields in India. The average yield of quinoa in South America is around 0.8 t/ha. One reason for low yields may be that grain chenopods are not often grown alone but are usually intercropped. In temperate areas, quinoa may yield 1-4 t/ha.
Handling after harvest
Due to their architecture, panicles do not dry easily. At harvest, seed moisture content may be around 20%. Artificial drying to 14% moisture may be necessary.
Germplasm collection of C. album is urgently needed, since the cultivation of fat hen in the Himalayas is definitely declining as a result of lack of crop improvement, and therefore farmers are substituting other, more profitable crops.
Peru and Bolivia have extensive collections of C. quinoa exceeding 2000 accessions. Other collections exist in Chile, Argentina, Ecuador, Colombia, the United States, Russia, Germany, England, Denmark and the Netherlands.
Cultivated Himalayan C. album has so far been neglected. It is practically unknown outside the region of cultivation.
Much breeding research is carried out on quinoa at agricultural research institutes in Peru, Chile, and other Latin American countries, in the United States (Colorado) and in some West European countries. The main breeding objectives are reduction of the saponin content, adaptation to specific environments, earliness, and resistance to premature sprouting and diseases. In Bolivia, two sweet cultivars were developed, "Sajama" and "Narino", which are most suitable for human consumption. "Sajama" yields up to 3 t/ha. In the United Kingdom, Denmark and the Netherlands, breeding programmes are conducted and cultivars adapted to European conditions are in development.
Quinoa prices may rise and production may increase as a consequence of its importance as a health food. It has potential as a specific starch-producing crop. The malted grains and flour hold promise as a weaning food for infants. Quinoa is also one of the best sources of leaf-protein concentrate.
Quinoa seems particularly promising for improving income and health in marginal upland areas. It could probably be cultivated in tropical highland regions, such as elevated parts of South-East Asia.
Given their similarity, one would expect both fat hen and quinoa to be intensively screened and their potential researched.
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