Ahipa, Yam bean
Pachyrhizus ahipa

Family: Fabaceae or Leguminosae

What it is like

Pachyrhizus ahipa is a PERENNIAL growing to 0.5 m (1ft 8in). It is frost tender. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. It can fix Nitrogen. Suitable for: light (sandy) and medium (loamy) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers moist soil.

Height (m): 0.5

Where it is found

Not known in a truly wild situation.

S. America.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 3

Root - raw or cooked. Thirst quenching and nutritious with an easily digested starch. The root is slow to discolour and remains crisp after slicing so it is often used in green and in fruit salads. Young seed pods - cooked and used like French beans. The pods must be thoroughly cooked in order to remove the toxic principle rotenone. It is thought that some varieties might be free of rotenone and their mature seeds could therefore be used as a protein crop.

Root: includes bulbs, corms, tubers, rhizomes etc.

Seedpod: things such as Okra, French and Runner beans.

Medicine

Rating: 0

Other

Rating:

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.

Insecticide: Kills insects.

Nitrogen Fixer: Plants that fix nitrogen in the soil

How it is grown

Prefers a light rich well-drained sandy soil. Sometimes cultivated for its edible root in the Andes, this plant is not frost hardy but could possibly be grown as a summer crop in cool temperate zones. There are some named varieties. When grown for its root the flowers should be removed, this is thought to increase the size of roots by up to 100%. The plant is day-neutral and so is much more likely to produce tubers in this country than the related jicama, Pachyrrizus tuberosus. It has produced good yields when grown in a greenhouse in Denmark. A faster-maturing plant than the jicama, it flowers in about 10 weeks from seed and the root is harvested after 5 - 6 months. 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.

Propagating it: Pre-soak the seed for 12 hours in warm water and then sow in early spring in a warm greenhouse. Germination should take place within 2 weeks. As soon as they are large enough to handle, prick out the seedlings into individual pots of rich soil and grow them on fast. Plant them out after the last expected frosts. Give the plants some protection, such as a cloche, until they are growing away well. Division of the root tubers in the autumn. Store the roots in a cool but frost-free place over the winter, planting them into pots in the greenhouse in early spring and planting them out after the last expected frosts. Give the plants some protection, such as a cloche, until they are growing away well. Cuttings.

Best place to grow: Cultivated Beds;

Habit: Perennial

Hardiness: 0-0

Growth:

Soil: Light (sandy), medium

Shade: No shade

Moisture: Moist

Things to keep in mind

The seed and green parts of the plant contain an insecticide (probably rotenone) and might be poisonous to people.

Its other names

Local names

Synonyms

Dolichos ahipa.