(1804)]] Lablab purpureus is a species of bean in the family Fabaceae. It is native to sub-Saharan Africa and it is cultivated throughout the tropics for food.[ Lablab purpureus. Tropical Forages.] English language common names include hyacinth bean,[ Lablab purpureus L. (Sweet). University of Agricultural Sciences, Bangalore, India.] Lablab is a monotypic taxon.[ Lablab purpureus, general information. University of Agricultural Sciences, Bangalore, India.]
Taxonomy
The name lablab which is also capitalized as its genus name is given by Robert Sweet from the previous name of Dolichos lablab by Carl Linnaeus, its epithet comes from .
Subspecific classification
According to the British biologist and taxonomist Bernard Verdcourt,
- there are two cultivated subspecies of Lablab purpureus (L.) Sweet:
- * Lablab purpureus subsp. bengalensis (Jacq.) Verdc. (Syn.: Dolichos bengalensis Jacq., Dolichos lablab subsp. bengalensis (Jacq.) Rivals, Lablab niger subsp. bengalensis (Jacq.) Cuf.)
- * Lablab purpureus subsp. purpureus
- in addition to one wild subspecies:
- * Lablab purpureus subsp. uncinatus
- of which a special variant with lobed leaflets exists only in Namibia:
- * Lablab purpureus var. rhomboïdeus (Schinz).
Description
The plant is variable due to extensive breeding in cultivation, but in general, they are Annual plant or short-lived Perennial plant . The wild species is perennial. The thick stems can reach in length. The leaves are made up of three pointed leaflets, each up to long. They may be hairy on the undersides. The inflorescence is made up of of many flowers. Some have white flowers, and others may have purplish or blue.[
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The fruit is a legume pod variable in shape, size, and color. It is usually several centimeters long and bright purple to pale green.[ Dolichos lablab. Floridata.] It contains up to four seeds. Depending on the cultivar, the seeds are white, brown, red, or black, sometimes with a white hilum. Wild plants have mottled seeds. The seed is about a centimeter long.[
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Origin and occurrence
The exact origin of the lablab bean remains uncertain. Evidence of wild varieties in eastern and southern Africa suggests these regions as the likely source,[USDA NRCS. "Plant Guide for Lablab (Lablab purpureus)."
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Over the centuries, the lablab has been distributed all over the world. Despite its preference for tropical and subtropical climates, it can be found in temperate climates such as Central and South America or Italy. Its adaptability to different climates increases its agricultural value.
Agronomy
The lablab bean remains most widespread in tropical and subtropical areas, particularly in eastern and southern Africa and India. There, the legume is grown primarily for food and fodder,[North Carolina State University Extension. "Lablab purpureus (Lablab)."
/ref> but its cultivation has declined sharply in many regions of Africa, despite renewed interest in its soil-improving functions in multiple cropping systems.]
Growing requirements
Lablab can grow on a wide range of soils, from sand to clay, within a pH range of 4.5 to 7.5. It is known to grow better in acidic conditions than most legumes, but does not grow well in poorly drained soils or in saline conditions.
Cultivation, harvest and storage
As there is a high degree of variability in phenotypes, including relative maturity, yield, susceptibility to insect attack and drought resistance, cultivation can vary accordingly depending on the accession and environmental factors[Valenzuela, H.; Smith J. (2002). Lablab. Departments of Tropical Plant and Soil Sciences and Natural Resources and Environmental Management
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It is generally accepted that harvesting fodder crops at the transition between the vegetative and reproductive stages gives the best compromise between yield and quality, as after this stage they become higher in fibre and lignin content and lower in protein content, leading to reduced digestibility and acceptability to livestock.
When lablab is stored as hay, the main challenge is the loss of dry matter from the leaves. Farmers suggest grinding it and storing it in bags. This can also prevent damage from direct sunlight or rain.
Soil improvements
Due to its symbiosis with nitrogen-fixing rhizobium bacteria, lablab bean has low soil fertility requirements and can be an important part of an agricultural system that improves soil nitrogen availability. The rate of nitrogen fixation has been shown to be highest when combined with phosphorus fertilisation, as phosphorus is required for rhizobium attachment to roots.
Breeding
Researchers suggest that the wide diversity of lablab germplasm has great potential for advancing the species as a promising alternative crop through selection and breeding.
Currently, most of the traditional cultivars grown have indeterminate growth habit, which has allowed farmers to harvest plants continuously.As such varieties aren't useful in the context of modern industrial farming, there has been a push to breed varieties that develop their seeds simultaneously, allowing all the beans to be collected in a single harvest. A side-effect of these breeding efforts has been a shortened vegetative phase, which reduces yield and hence economic value
Uses
The hyacinth bean is an old domesticated pulse and multi-purpose crop.
Due to seed availability of one forage cultivar (cv. Rongai), it is often grown as forage for livestock[ Lablab purpureus. Grassland Species Profiles. Food and Agriculture Organization.] and as an ornamental plant.[ Lablab purpureus. Missouri Botanical Garden.] In addition, it is cited both as a medicinal plant and a poisonous plant.[ Lablab purpureus. Plants for a Future. ][ Dolichos lablab ( Lablab purpureus). Poisonous Plants of North Carolina. North Carolina State University.]
The fruit and beans are edible if boiled well with several changes of the water.[ It has been shown that there is a wide range of cyanogenic potential among the varieties.][*]
The leaves are eaten raw or cooked like spinach.[ The flowers can be eaten raw or steamed. The root can be boiled or baked for food. The seeds are used to make tofu and tempeh.][
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Food in South Asia
In Bangladesh and West Bengal, the green pods along with the beans, known as sheem (শিম), are cooked as vegetables or cooked with fish as a curry.
In Gujarat, lablab is called surti papdi.
In Kerala, it is known as amarakka, avara or amara payar (Malayalam: അമര പയർ).
In Tamil Nadu, it is called avarai or avaraikkaay (Tamil: அவரைக்காய் / அவரை).
In Maharashtra, dry preparations with green masala are often made out of these green beans (ghevda varieties; Shravan ghevda (French beans), bajirao ghevda, ghevda, walwar, pavta sheng) mostly at the end of monsoon season during fasting festivals of Shravan month.
In Karnataka, the hyacinth bean is made into curry ( avarekalu saaru) (), salad ( avarekaalu usli), added to upma ( avrekaalu uppittu), and as a flavoring to Akki rotti. Sometimes the outer peel of the seed is removed and the inner soft part is used for a variety of dishes. This form is called hitakubele avarekalu, which means "pressed ( hitaku) hyacinth bean," and a curry known as hitikida avarekaalu saaru is made out of the deskinned beans.
In Telangana and Andhra Pradesh, the bean pods are cut into small pieces and cooked as a spicy curry in the Pongal festival season. Sometimes the outer peel of the seed when tender and soaked overnight is removed and the inner soft part is used for a variety of dishes. This form is called pitakapappu hanupa/anapa, which means "pressed ( pitaku) hyacinth bean, and a curry known as pitikina anapaginjala chaaru/pitaka pappu is made from the deskinned beans and eaten along with Pearl millet bread.
Food in Southeast and East Asia
In Myanmar, lablab beans are used to make a braised Burmese curry hnat (ပဲကြီးနှပ်).
In Huế, Vietnam, hyacinth beans are the main ingredient of the dish chè đậu ván (Hyacinth Bean Sweet Soup).
In China, the seeds are known as Bai Bian Dou. They are usually dried and baked before being used in traditional Chinese herbal remedies to strengthen the spleen, reduce heat and dampness, and promote appetite.
Food tradition in East Africa
In Kenya, the bean, known as njahe or njahi,[
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Medicinal use
Taiwanese researchers found that a carbohydrate-binding protein (i.e. a legume lectin) from lablab beans effectively blocks the infections of influenza viruses and SARS-CoV-2.
Gallery
File:BCBG lablab purpureus 02.jpg|Foliage
File:Lablab purpureus.JPG|Flowers
Image:Lablab purpureus Steve Hurst 1.jpg|Seeds
Further reading
Sources
External links
