Lablab

The plant is variable due to extensive breeding in cultivation, but in general, they are annual or short-lived perennial vines. The wild species is perennial. The thick stems can reach six meters in length. The leaves are made up of three pointed leaflets each up to 15 centimeters long. They may be hairy on the undersides. The inflorescence is made up of racemes of many flowers. Some cultivars have white flowers, and others may have purplish or blue.[2] The fruit is a legume pod variable in shape, size, and color. It is usually several centimeters long and bright purple to pale green.[7] It contains up to four seeds. The seeds are white, brown, red, or black depending on the cultivar, sometimes with a white hilum. Wild plants have mottled seeds. The seed is about a centimeter long.[2]

Other common names include Tonga bean, papaya bean, poor man bean (Australia), Seim (Trinidad and Tobago, Guyana, and Suriname), and butter bean (Caribbean).[8]

According to the British biologist and taxonomist Bernard Verdcourt,[9]

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).

The hyacinth bean is an old domesticated pulse and multi-purpose crop.[10][11][12] L. purpureus has been cultivated in India as early as 2500 BC.[13]

Due to seed availability of one forage cultivar (cv. Rongai), it is often grown as forage for livestock[14] and as an ornamental plant.[15] In addition, it is cited both as a medicinal plant and a poisonous plant.[16][17]

The fruit and beans are edible if boiled well with several changes of the water.[17] Otherwise, they are toxic due to the presence of cyanogenic glycosides, glycosides that are converted to hydrogen cyanide when consumed. Signs of poisoning include weakness, vomiting, dyspnea, twitching, stupor, and convulsions.[17] It has been shown that there is a wide range of cyanogenic potential among the varieties.[18]

The leaves are eaten raw or cooked like spinach.[12] 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.[7]

In India its called ′Surti Papdi′.[19] 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 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 spleen, reduce heat and dampness, and promote appetite.[20]

In Kerala, it is known as Amarakka, Avara or Amara Payar (Malayalam: അമര പയർ ).[21] The beans as well as the bean pods are used in cooking curries.[22] The bean pods are also used (along with spices) for preparing stir-fried dish known as Thoran.[23]

In Maharashtra, dry preparations with green masala is often made out of these green beans (Ghevda varieties - Shravan ghevda (French beans), Bajirao Ghevda, Ghevda, Walwar, Pavta sheng..) mostly found at the end of monsoon during fasting festivals of Shravan month.

In Karnataka, the hyacinth bean is made into curry (avarekalu saaru)(Kannada: ಅವರೆಕಾಳು ಸಾರು), salad (avarekaalu usli), added to upma (avrekaalu uppittu), and as a flavoring to Akki rotti. Sometimes the outer peel of the seed is taken out and the inner soft part is used for a variety of dishes. This form is called hitakubele avarekalu, which means "pressed (hitaku) hyancinth bean," and a curry known as Hitikida Avarekaalu Saaru is made out of the deskinned beans.

In Telangana and Andra Pradesh, the bean pods are cut into small pieces and cooked as spicy curry in Pongal festival season. Sometimes the outer peel of the seed when tender and soaked over night is taken out and the inner soft part is used for a variety of dishes. This form is called pitakapappu,hanupa/anapa, which means "pressed (pitaku) hyancinth bean, and a curry known as Pitikida Anapaginjala Chaaru is made out of this deskinned beans along with bajra bread; it has been a very special delicacy for centuries.

In Huế, Vietnam, hyacinth beans are the main ingredient of the dish chè đậu ván (Hyacinth Bean Sweet Soup).[24]

In Kenya, the bean called 'Njahe' is popular among several communities, especially the Kikuyu. 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.[25] 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.[25][26] 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.[27]

• 
  Foliage
• 
  Flowers
• 
  Seeds

• Fakhoury, A. M.; Woloshuk, C. P. (2001). "Inhibition of Growth of Aspergillus flavusand Fungal α-Amylases by a Lectin-Like Protein from Lablab purpureus". Molecular Plant-Microbe Interactions. 14 (8): 955–61. doi:10.1094/MPMI.2001.14.8.955. PMID 11497467.
• Hendricksen, R.; Minson, D. J. (2009). "The feed intake and grazing behaviour of cattle grazing a crop of Lablab purpureus cv. Rongai". The Journal of Agricultural Science. 95 (3): 547–54. doi:10.1017/S0021859600087955.
• Hendricksen, RE; Poppi, DP; Minson, DJ (1981). "The voluntary intake, digestibility and retention time by cattle and sheep of stem and leaf fractions of a tropical legume (Lablab purpureus)". Australian Journal of Agricultural Research. 32 (2): 389–98. doi:10.1071/AR9810389.
• Humphry, E; Konduri, V; Lambrides, J; Magner, T; McIntyre, L; Aitken, B; Liu, J (2002). "Development of a mungbean (Vigna radiata) RFLP linkage map and its comparison with lablab (Lablab purpureus) reveals a high level of colinearity between the two genomes". Theoretical and Applied Genetics. 105 (1): 160–6. doi:10.1007/s00122-002-0909-1. PMID 12582573.
• Liu, C. J. (1996). "Genetic diversity and relationships among Lablab purpureus genotypes evaluated using RAPD as markers". Euphytica. 90 (1): 115–9. doi:10.1007/BF00025167 (inactive 2020-04-29).
• Maass, Brigitte L. (2006). "Changes in seed morphology, dormancy and germination from wild to cultivated germplasm of the hyacinth bean (Lablab purpureus (L.) Sweet)". Genetic Resources and Crop Evolution. 53 (6): 1127–35. doi:10.1007/s10722-005-2782-7.
• Maass, Brigitte L.; Usongo, Macalister F. (2007). "Changes in seed characteristics during the domestication of the lablab bean (Lablab purpureus (L.) Sweet: Papilionoideae)". Australian Journal of Agricultural Research. 58 (1): 9–19. doi:10.1071/ar05059.
• Maass, Brigitte L.; Jamnadass, Ramni H.; Hanson, Jean; Pengelly, Bruce C. (2005). "Determining sources of diversity in cultivated and wild Lablab purpureus related to provenance of germplasm using amplified fragment length polymorphism (AFLP)". Genetic Resources and Crop Evolution. 52 (5): 683–95. doi:10.1007/s10722-003-6019-3.
• Pengelly, Bruce C.; Maass, Brigitte L. (2001). "Lablab purpureus (L.) Sweet – diversity, potential use and determination of a core collection of this multi-purpose tropical legume". Genetic Resources and Crop Evolution. 48 (3): 261–72. doi:10.1023/A:1011286111384.
• Trinick, M. J. (1980). "Relationships Amongst the Fast-growing Rhizobia of Lablab purpureus, Leucaena leucocephala, Mimosa spp., Acacia farnesiana and Sesbania grandiflora and their Affinities with Other Rhizobial Groups". Journal of Applied Bacteriology. 49 (1): 39–53. doi:10.1111/j.1365-2672.1980.tb01042.x.
• Vanlauwe, B.; Nwoke, O.C.; Diels, J.; Sanginga, N.; Carsky, R.J.; Deckers, J.; Merckx, R. (2000). "Utilization of rock phosphate by crops on a representative toposequence in the Northern Guinea savanna zone of Nigeria: Response by Mucuna pruriens, Lablab purpureus and maize". Soil Biology and Biochemistry. 32 (14): 2063–77. doi:10.1016/S0038-0717(00)00149-8.

Wikimedia Commons has media related to Lablab purpureus (Hyacinth bean).

• Dolichos bean, Lablab purpureus (L.) Sweet by the University of Agricultural Sciences, Bangalore, India
• Avadhani, Ramesh (Spring 2006). "The Bangalore Beans". Mood Indico. Archived from the original on 2013-07-24. Retrieved 2007-01-08.
• JSTOR Global Plants: Lablab purpureus