Lablab

Lablab purpureusis a species ofbeanin the familyFabaceae. It is native to sub-Saharan Africa and it is cultivated throughout thetropicsfor food.English languagecommon names includehyacinth bean,lablab-beanbonavist bean/pea,dolichos bean,seimorsem bean,lablab bean,Egyptian kidney bean,Indian bean,batawandAustralian pea.Lablabis amonotypic genus.
The namelablabwhich is also capitalized as its genus name is given byRobert Sweetfrom the previous name ofDolichoslablabbyCarl Linnaeus, its epithet comes fromArabic:لَبْلَاب,romanized:lablāb.
According to the British biologist and taxonomistBernard Verdcourt,
The plant is variable due to extensive breeding in cultivation, but in general, they areannualor short-livedperennialvines. The wild species is perennial. The thick stems can reach 6 m (20 ft) in length. The leaves are made up of three pointedleaflets, each up to 15 cm (5.9 in) long. They may be hairy on the undersides. Theinflorescenceis made up ofracemesof many flowers. Somecultivarshave white flowers, and others may have purplish or blue.
The fruit is alegumepod variable in shape, size, and color. It is usually several centimeters long and bright purple to pale green.It contains up to four seeds. Depending on the cultivar, the seeds are white, brown, red, or black, sometimes with a whitehilum. Wild plants have mottled seeds. The seed is about a centimeter long.
The exact origin of the lablab bean remains uncertain. Evidence of wild varieties in eastern and southernAfricasuggests these regions as the likely source,although some theories suggestIndiaas the origin.
Over the centuries, the lablab has been distributed all over the world. Despite its preference for tropical and subtropical climates, it can be found intemperate climatessuch as Central and South America orItaly. Its adaptability to different climates increases its agricultural value.
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,but its cultivation has declined sharply in many regions of Africa, despite renewed interest in its soil-improving functions in multiple cropping systems.One of the main reasons for this decline is the replacement of faba bean by the common bean, but factors such as the many processing steps and antinutritional factors may also have played a role.In addition, lablab is often grown in home garden systems or mixed cropping systems, such as in Southeast Asia, making estimates of global production difficult.
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.Average daily temperatures of 18-30°C and annual rainfall of 700-3000 mm allow lablab cultivation. However, it can tolerate temperatures as low as 4°C for short periods. The seedlings grow slowly, but once established they compete well with weeds and are able to tolerate drought or shade.Lablab requires well-drained soils as it is very intolerant of waterlogged or flooded conditions.
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 factorsHowever, when lablab is first planted in a field, it is beneficial to inoculate the seeds with specialised rhizobium bacteria. The seeds are either broadcast and then covered, or sown to a depth of 5 cm using the drillseed technique. The seedbed must be kept free of weeds in the early stages of growth, as the young plant succumbs easily to weed pressure.
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.
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.Its cultivation also increases potassium and phosphorus availability.These soil-improving properties make lablab attractive for intercropping, mixed cropping systems and as a green manure.For example, intercropping lablab maize can improve multiple soil functions, including microbial diversity, with minimal to no loss of maize yield.
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 valueBreeding objectives also differ between countries and between uses of the plants. In Australia, the focus is on creating a variety for fodder use by crossing pure line varieties with wild varieties from Africa, while researchers in Bangladesh and Africa are trying to increase the yield of existing varieties to increase their value in the food production system.
The hyacinth bean is an old domesticated pulse and multi-purpose crop.L. purpureushas been cultivated in India as early as 2500 BC.
Due to seed availability of one forage cultivar (cv. Rongai), it is often grown asforageforlivestockand as anornamental plant.In addition, it is cited both as amedicinal plantand apoisonous plant.
The fruit and beans are edible if boiled well with several changes of the water.Otherwise, they are toxic due to the presence ofcyanogenicglycosides,glycosidesthat are converted tohydrogen cyanidewhen consumed. Signs of poisoning include weakness, vomiting,shortness of breath, twitching,stupor, andconvulsions.It has been shown that there is a wide range of cyanogenic potential among the varieties.
The leaves are eaten raw or cooked likespinach.The flowers can be eaten raw or steamed. The root can be boiled or baked for food. The seeds are used to maketofuandtempeh.
InBangladeshandWest Bengal, the green pods along with the beans, known assheem(শিম), are cooked as vegetables or cooked with fish as acurry.
InGujarat, lablab is calledsurti papdi.In Maharashtra, they are known asval papdi.In both states, they are commonly used to make sautéed, spiced vegetable dishes calledsabjis.
InKerala, it is known asamarakka,avaraoramara payar(Malayalam:അമര പയർ).The beans as well as the bean pods are used in cooking curries.The bean pods are also used (along with spices) for preparing a stir-fried dish known asthoran.
InTamil Nadu, it is calledavaraioravaraikkaay(Tamil: அவரைக்காய் / அவரை).The entire bean is used in cooking dry curriesand in sauces/gravies such assambar.The seed alone is used in many recipes and is referred to asmochai(Tamil: மொச்சை / மொச்சைக்கொட்டை).
InMaharashtra, 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 ofShravanmonth.
InKarnataka, the hyacinth bean is made into curry (avarekalu saaru) (Kannada:ಅವರೆಕಾಳು ಸಾರು), salad (avarekaalu usli), added to upma (avrekaaluuppittu), and as a flavoring toAkki 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 calledhitakubele avarekalu, which means "pressed (hitaku) hyacinth bean," and a curry known ashitikida avarekaalu saaruis made out of the deskinned beans.
InTelanganaandAndhra Pradesh, the bean pods are cut into small pieces and cooked as a spicy curry in thePongalfestival 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 calledpitakapappu 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 withbajrabread.
In Myanmar, lablab beans are used to make a braisedBurmese curryhnat(ပဲကြီးနှပ်).They are also crisp-fried and served inBurmese pickled tea leaf salad.
InHuế,Vietnam, hyacinth beans are the main ingredient of the dishchè đậu ván(Hyacinth Bean Sweet Soup).
InChina, the seeds are known asBai 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.
InKenya, the bean, known asnjaheornjahi,is popular among several communities, especially theKikuyu. Seasons were actually based on it, i.e., the Season of Njahe (Kīmera kīa njahī). It is thought to encourage lactation and has historically been the main dish for breastfeeding mothers.Beans are boiled and mashed with ripe and/or semi-ripe bananas, giving the dish a sweet taste.  Today the production is in decline in eastern Africa.This is partly attributed to the fact that under colonial rule in Kenya, farmers were forced to give up their local bean in order to produce common beans (Phaseolus vulgaris) for export.
Taiwanese research found that a carbohydrate-binding protein (i.e. alegume lectin) from lablab beans effectively blocks the infections of influenza viruses and SARS-CoV-2.