''Vigna angularis'', also known as the adzuki bean , azuki bean, aduki bean, red bean, or red mung bean, is an annual

vine A vine (Latin ''vīnea'' "grapevine", "vineyard", from ''vīnum'' "wine") is any plant with a growth habit of trailing or scandent (that is, climbing) stems, lianas or runners. The word ''vine'' can also refer to such stems or runners themsel ...

widely cultivated throughout

East Asia East Asia is the eastern region of Asia, which is defined in both geographical and ethno-cultural terms. The modern states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. China, North Korea, South Korea ...

for its small (approximately long) bean. The

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture ...

s most familiar in East Asia have a uniform red color, but there are also white,

black Black is a color which results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white ha ...

, gray, and variously mottled varieties. Scientists presume ''Vigna angularis'' var. ''nipponensis'' is the

progenitor In genealogy, the progenitor (rarer: primogenitor; german: Stammvater or ''Ahnherr'') is the – sometimes legendary – founder of a family, line of descent, clan or tribe, noble house, or ethnic group.. Ebenda''Ahnherr:''"Stammvater eines ...

Origin and diversity

Speciation and domestication

The wild ancestor of cultivated adzuki bean is probably ''Vigna angularis'' var. ''nipponensis'', which is distributed across Japan, Korea, China, Nepal and Bhutan. Speciation between ''Vigna angularis'' var. ''nipponensis'' and ''Vigna angularis'' var. ''angularis'' occurred around years ago. Archaeologists estimate it was domesticated around 3000 BC. However, adzuki beans (as well as soybeans) dating from 3000 BC to 2000 BC are indicated to still be largely within the wild size range. Enlarged seeds occurred during the later

Bronze Age The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second pri ...

Iron Age The Iron Age is the final epoch of the three-age division of the prehistory and protohistory of humanity. It was preceded by the Stone Age ( Paleolithic, Mesolithic, Neolithic) and the Bronze Age ( Chalcolithic). The concept has been mostly ...

, periods with plough use. Domestication of adzuki beans resulted in a trade-off between yield and seed size. Cultivated adzuki beans have fewer but longer pods, fewer but larger seeds, a shorter stature, and also a smaller overall seed yield than wild forms. The exact place of domestication is not known; multiple domestication origins in East Asia have been suggested.

Breeding

In Japan, the adzuki bean was one of the first crops subjected to scientific

plant breeding Plant breeding is the science of changing the traits of plants in order to produce desired characteristics. It has been used to improve the quality of nutrition in products for humans and animals. The goals of plant breeding are to produce cr ...

. Important breeding traits are yield, pureness of the bean colour, and the maturing time. Separate cultivars with smaller seeds and higher biomass are bred for fodder production and as

green manure In agriculture, a green manure is a crop specifically produced to be incorporated into the soil while still green. Typically, the green manure's biomass is incorporated with a plow or disk, as is often done with (brown) manure. The primary goal ...

. Locally adapted cultivars are available in China, Japan, Korea, and Taiwan. More than 300 cultivars/landraces/breeding lines are registered in Japan. Moreover, China (Institute of Crop Germplasm Resources (CAAS), Beijing, more than 3700 accessions) and Japan (Tokachi Agricultural Experiment Station, Hokkaido, about 2500 accessions) accommodate large germplasm collections of adzuki bean.

Weed forms

Weed forms of adzuki bean frequently occur in Japan. The wide spread of weed forms is due to adaptation to human-disturbed habitats, escapes of old cultivars, and natural establishment from derivatives of hybrids between cultivars and wild forms. In contrast to wild forms, the weed forms of adzuki bean are used as a substitute for the cultivated form and consumed as sweet beans, especially if cultivated adzuki beans are attacked by pests. However, in cultivated gardens the weed form is recognized as contamination and lowers the seed quality of adzuki cultivars.

Names

The name ''adzuki'' is a transliteration of the native Japanese アヅキ, as it was spelled according to

historical kana orthography The , or , refers to the in general use until orthographic reforms after World War II; the current orthography was adopted by Cabinet order in 1946. By that point the historical orthography was no longer in accord with Japanese pronunciatio ...

. The name is also transliterated as ''azuki'', reflecting the modern spelling アズキ, or less commonly as ''aduki'', according to an alternate system of romanization. All are meant to represent the same Modern Japanese pronunciation, ''azuki''. Japanese also has a Chinese

loanword A loanword (also loan word or loan-word) is a word at least partly assimilated from one language (the donor language) into another language. This is in contrast to cognates, which are words in two or more languages that are similar because ...

, , which means "small bean", its counterpart being the

soybean The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses. Traditional unfermented food uses of soybeans include soy milk, from which tofu ...

. It is common to write in

kanji are the logographic Chinese characters taken from the Chinese script and used in the writing of Japanese. They were made a major part of the Japanese writing system during the time of Old Japanese and are still used, along with the subsequ ...

but pronounce it as ''azuki'' ', an example of '. In China, the corresponding name () still is used in botanical or agricultural parlance, however, in everyday Chinese, the more common terms are ' () and ' (), both meaning "red bean", because almost all Chinese cultivars are uniformly red. In English the beans are often described as "red beans" in the context of Chinese cuisine, especially in reference to

red bean paste Red bean paste () or red bean jam, also called adzuki bean paste or ''anko'' (a Japanese word), is a paste made of red beans (also called "adzuki beans"), used in East Asian cuisine. The paste is prepared by boiling the beans, then mashing or ...

, but the term is not otherwise used as other beans are also red in color. In normal contexts, "red

cowpeas The cowpea (''Vigna unguiculata'') is an annual herbaceous legume from the genus '' Vigna''. Its tolerance for sandy soil and low rainfall have made it an important crop in the semiarid regions across Africa and Asia. It requires very few input ...

" have been used to refer to this bean. In Korean, adzuki beans are called ' () and it contrasts with ' (, "bean"), rather than being considered a type of it. ' ("beans") without qualifiers usually means

s. In Vietnamese it is called ' (literally: red bean). In some parts of India, the beans are referred to as "red chori". In

Punjabi Punjabi, or Panjabi, most often refers to: * Something of, from, or related to Punjab, a region in India and Pakistan * Punjabi language * Punjabi people * Punjabi dialects and languages Punjabi may also refer to: * Punjabi (horse), a British Th ...

it is called ' and is a common ingredient of chaat. In Marathi, it is known as ' (), literally meaning 'red

cowpea The cowpea (''Vigna unguiculata'') is an annual herbaceous legume from the genus ''Vigna''. Its tolerance for sandy soil and low rainfall have made it an important crop in the semiarid regions across Africa and Asia. It requires very few inputs, ...

'. In Iraq its name is ' () meaning "red cowpeas".

Cultivation

Area and yield

The adzuki bean is mainly cultivated in China ( ha), Japan ( ha), South Korea ( ha), and Taiwan ( ha) (data published 2006). The bean is also grown commercially in the US, South America, and India, as well as New Zealand, Congo, and Angola. In Japan, the adzuki bean is the second most important legume after the

soy bean The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses. Traditional unfermented food uses of soybeans include soy milk, from which tofu and ...

; its 1998 annual yield of this crop was around 100,000 tons. With a consumption of about 140,000 t/year (data published 2006), Japan is also the most important importer of adzuki beans. The imports are received from China, Korea, Colombia, Taiwan, US, Thailand, and Canada. The bean yields per area spread over a broad range due to differing cultivation intensity. Amounts of 4 to 8 dt/ha are reported, but in Japan and China yields between 20 and 30 dt/ha are reached.

Ecological requirements

Optimal temperature range for adzuki bean growth is between 15 °C and 30 °C. The crop is not frost-hardy and needs soil temperatures above 6–10 °C (30–34 °C optimal) for

germination Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, fe ...

. Hot temperatures stimulate vegetative growth and are therefore less favorable for pea production. The adzuki bean is usually not irrigated. Annual rainfall ranges from 500 to 1750 mm in areas where the bean is grown. The plant can withstand

drought A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, an ...

but severe reduction in yield is expected. The cultivation of the adzuki bean is possible on preferably well drained soils with pH 5–7.5. Fertilizer application differs widely depending on expected yield but is generally similar to soybean. Due to nodulation with rhizobia,

nitrogen fixation Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but also in industry. Atmo ...

of up to 100 kg/ha is possible.

Production

The sowing of the peas is in 2–3 cm depth in rows 30–90 cm apart and 10–45 cm within the row. Rarely seeds are sown by broadcast. The amount of seeds ranges between 8–70 kg/ha. Growth of the crop is slow, therefore weed control is crucial mainly between germination and flowering. Cultivation systems differ largely among different countries. In China adzuki bean is often grown in

intercrops Intercropping is a multiple cropping practice that involves growing two or more crops in proximity. In other words, intercropping is the cultivation of two or more crops simultaneously on the same field. The most common goal of intercropping is ...

with maize, sorghum and millet while in Japan the bean is grown in

crop rotation Crop rotation is the practice of growing a series of different types of crops in the same area across a sequence of growing seasons. It reduces reliance on one set of nutrients, pest and weed pressure, and the probability of developing resistant ...

s. Harvest of the peas should not be done as long as moisture content of the seed is higher than 16%.

Pests and diseases

Fungal and bacterial diseases of the adzuki bean are powdery mildew, brown stem rot, and bacterial

blight Blight refers to a specific symptom affecting plants in response to infection by a pathogenic organism. Description Blight is a rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral orga ...

. Furthermore, pests such as the adzuki pod worm, Japanese butterbur borer, and cutworm attack the crop. The bean weevil is an important storage pest.

Botany

The description of the adzuki bean can vary between authors because there are both wild and cultivated forms of the plant. The adzuki bean is an annual, rarely biennial bushy erect or twining herb usually between 30 and 90 centimeters high. There exist climbing or prostrate forms of the plant. The stem is normally green and sparsely pilose.

Roots

The adzuki bean has a taproot type of root system that can reach a depth of 40–50 cm from the point of seed germination.

Leaves

The leaves of the adzuki bean are

trifoliate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...

pinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, an ...

and arranged alternately along the stem on a long petiole. Leaflets are ovate and about 5–10 cm long and 5–8 cm wide.

Flowers

Adzuki flowers are papilionaceous and bright yellow. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are forme ...

is an axillary false

raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

consisting of six to ten (two to twenty) flowers.

Fruits

Adzuki pods are smooth, cylindrical and thin-walled. The colour of the pods is green turning white to grey as they mature. The size is between 5–13 cm × 0.5 cm with 2 to 14 seeds per pod. Pod shatter during seed ripening and harvesting might be a difficulty under certain conditions.

Seeds

The seeds are smooth and subcylindric with a length of 5.0-9.1 mm, width of 4.0-6.3 mm, thickness of 4.1-6.0 mm. The thousand kernel weight is between 50 and 200 g. There are many different seed colours from maroon to blue-black mottled with straw.

Physiology

The emergence of the seedlings is hypogeal and takes 7–20 days. Compared to other pulses the growth of the plant is slow. Normally the adzuki plant reaches maturity between 80 and 120 days depending on the cultivar and the environmental conditions. Flowering lasts 30–40 days. Commonly the plant self-pollinates but

cross-pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, bird ...

also exists.

Culinary uses

In East Asian cuisine, the adzuki bean is commonly sweetened before eating. In particular, it is often boiled with sugar, producing red bean paste, a very common ingredient in all of these cuisines. It also is common to add flavoring to the bean paste, such as chestnut. Red bean paste is used in many Chinese dishes, such as tangyuan, zongzi,

mooncake A mooncake () is a Chinese bakery product traditionally eaten during the Mid-Autumn Festival (中秋節). The festival is about lunar appreciation and Moon watching, and mooncakes are regarded as a delicacy. Mooncakes are offered between ...

s, baozi, and red bean ice. It also serves as a filling in

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the n ...

ese sweets such as anpan, dorayaki, imagawayaki, manjū,

monaka is a Japanese sweet made of azuki bean paste sandwiched between two thin crisp wafers made from mochi. The wafers can have the shape of a square, a triangle, or may be shaped like cherry blossoms, chrysanthemums, and so on. The azuki bean paste ...

, anmitsu, taiyaki, and daifuku. A more liquid version, using adzuki beans boiled with sugar and a pinch of salt, produces a sweet dish called hong dou tang. Some East Asian cultures enjoy red bean paste as a filling or topping for various kinds of waffles, pastries, baked buns, or biscuits. Adzuki beans are commonly eaten sprouted or boiled in a hot, tea-like drink. Traditionally in Japan, rice with adzuki beans ( 赤飯; ''

sekihan Red bean rice, called ''patbap'' () in Korean, ''sekihan'' () in Japanese, and ''hóngdòu fàn'' () in Chinese, is an East Asian rice dish consisting of rice cooked with red beans. East Asian varieties China Hóngdòu fàn (红豆饭) is a ...

'') is cooked for auspicious occasions. Adzuki beans are used in amanattō and

ice cream Ice cream is a sweetened frozen food typically eaten as a snack or dessert. It may be made from milk or cream and is flavoured with a sweetener, either sugar or an alternative, and a spice, such as cocoa or vanilla, or with fruit such as ...

with the whole bean or as paste.

Nutritional information

Cooked adzuki beans are 66% water, 25%

carbohydrates In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or m ...

, including 7%

dietary fiber Dietary fiber (in British English fibre) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers are diverse in chemical composition, and can be grouped generally by t ...

, 8%

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

, and contain negligible fat (table). In a 100-gram reference amount, cooked beans provide of food energy, a moderate to high content (10% or more of the Daily Value, DV) of the B vitamin folate (30% DV), and several dietary minerals (11% to 27% DV, table).

Gallery

File:Pat kalguksu (red bean noodles).jpg, ''Patkalguksu'' (

Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic ...

n red bean kalguksu) File:Matcha muffin with sweetened azuki beans.jpg, Matcha muffin File:Red bean paste anko.JPG,

Red bean paste Red bean paste () or red bean jam, also called adzuki bean paste or ''anko'' (a Japanese word), is a paste made of red beans (also called "adzuki beans"), used in East Asian cuisine. The paste is prepared by boiling the beans, then mashing or ...

References

External links

Illustrated Plant Genetic Resources Database

* {{DEFAULTSORT:Adzuki Bean Articles containing video clips Edible legumes Japanese cuisine Korean cuisine Vigna Yunnan cuisine