Closely related to Pachyrrhizus tuberosus[
Cacara bulbosa Rumphius ex Du Petit-Thouars
Cacara erosa (L.) Kuntze
Cacara palmatiloba (Moc. & Sessé ex DC.) Kuntze
Dolichos articulatus Lam.
Dolichos bulbosus L.
Dolichos erosus L.
Dolichos palmatilobus Moc. & Sessé ex DC.
Pachyrhizus angulatus Rich. ex DC.
Pachyrhizus articulatus Duchass. ex Walp.
Pachyrhizus bulbosus (L.) Kurz
Pachyrhizus jicamas Blanco
Pachyrhizus palmatilobus (Moc. & Sessé ex DC.) Benth. & Hook.f.
Pachyrhizus panamensis R.T.Clausen
Pachyrhizus strigosus R.T.Clausen
Pachyrhizus vernalis R.T.Clausen
Robynsia lobata M.Martens & Galeotti
Robynsia macrophylla M.Martens & Galeotti
Stizolobium bulbosum (L.) Spreng.
Stizolobium domingense Spreng.
Taeniocarpum articulatum (Lam.) Desv.
Common Name: Yam Bean
Yam bean is a perennial climbing or trailing plant producing annual, twining stems 2 - 6 metres long from a tuberous rootstock[
The plant is often cultivated for its edible root and seedpods in tropical areas[
Seeds and leaves are poisonous[
]. The leaves, mature seedpods and the seeds contain a poisonous glucoside[
Central America - Mexico.
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Plants are tolerant of a wide range of climatic conditions but grows best in lowland tropical areas at elevations up to 1,000 metres and a moderate rainfall[
]. The plant grows best in areas where the mean minimum temperature is about 20°c and the maximum is 30°c, though they can succeed where they are 15 - 36°c[
]. It prefers an annual rainfall in the range 1,300 - 1,700mm, but can tolerate 250 - 7,000mm[
Grows best in a sunny position[
]. Tolerates a wide range of soils[
]. Prefers a light, rich, well-drained, sandy soil[
]. Dislikes water-logged soils[
]. The plant prefers a pH in the range 6.5 - 8, but can tolerate 4.3 - 8[
Immature pods are ready for harvest about 200 - 240 days from sowing[
Tubers may be harvested after 150 - 270 days, before they become fibrous[
]. In warmer parts of Mexico with light, rich soil, mature tubers are commonly harvested after only 90 days[
Seed crops takes about 300 days to mature[
A short-day plant, it requires between 11 - 13 hours of daylight hours per day in order to initiate tuber production[
], though vegetative growth is normal even in relatively long days of 14 - 15 hours[
When grown for its edible root the flowers and seedpods should be removed[
There are some named forms[
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[
Edible root - raw or cooked[
]. Crisp, sweet and juicy, it tastes somewhat like an apple when raw and a water chestnut when cooked[
]. The root stays crisp and does not discolour after being cut[
]. It also stays crisp after being cooked, which makes it a popular substitute for water chestnuts in Chinese cooking[
]. A starch extracted from the root is used in custards and puddings[
]. The root is harvested before it matures and becomes fibrous, when the plant has been growing for about 6 months and the tuber weighs about 2 kilos[
]. Mature tubers can reach 2 metres long and weigh up to 20 kilos[
Young seedpods - cooked and used as a vegetable[
]. They must be thoroughly cooked in order to destroy the poisonous principle rotenone[
The plant can be used as a green manure[
The plant contains rotenone, the active ingredient in the insecticide 'derris', and it has the potential to be used as an insecticide[
]. Derris is a relatively safe insecticide in that it does not affect warm-blooded animals and also breaks down into harmless substances with 24 hours of being used. It does, however, kill some beneficial insects and is also toxic to fish and amphibians[
Pre-soak the seed for 12 hours in warm water and then sow in situ[
Division of the root tubers.
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