Jicama Seed

Jicama is a climbing tropical legume with trifoliate leaves, purple-blue or whitish flowers, and a large turnip-shaped tuberous root. The seeds develop in flat pods, which are about ten to fifteen centimeters long and contain several seeds each.

The seeds are flat, squarish to rounded, about one centimeter across, and brown to dark brown with a hard, glossy surface. Farmers often remove flowers before they set seed, because the plant puts more energy into the root when seed production is limited.

Seeds are sold by seed companies for planting. Mature seeds are not a food product, and the edible parts of the plant are the tuberous root, and in some places the very young tender pods.

Pachyrhizus erosus is native to Mexico and Central America, where it was domesticated in pre-Columbian times, and it is the most widely grown of the yam beans. Spanish traders carried it from Mexico to the Philippines, and from there it spread through Southeast Asia and China, where it is now a popular crop.

The word jicama comes from Nahuatl xicamatl, the name given to the edible root. The genus name Pachyrhizus is Greek for thick root, and erosus, meaning gnawed or jagged, refers to the toothed leaflet edges. In parts of Asia the vegetable is known by names such as bangkuang in Indonesia, sengkuang in Malaysia and mankwang in the Philippines.

Jicama is known from ancient Mesoamerica, where it was eaten raw with salt, lime and chili, and the Aztec name xicamatl shows its long cultural presence. The root's crisp texture and mild sweetness made it a refreshing food in warm climates.

After the Spanish arrived in the sixteenth century, the plant was spread along the Manila galleon trade route to the Philippines and then across Asia, where it was adopted in Chinese, Thai, Vietnamese and Indonesian cooking. In Asia it became a staple in dishes such as spring rolls and salads.

The seeds' toxicity was also recognized. They contain rotenone, a compound that is poisonous to fish and insects, and in some places the crushed seeds were used as a fish poison or insect repellent. Rotenone later became a well-known botanical insecticide, though its use has been restricted in many countries because of toxicity concerns. Modern growers keep seeds only for propagation and sow them in warm soil in spring.

The seeds are used almost exclusively for growing new plants. Growers pick one or two pods per plant for seed and remove the other flowers, which gives bigger roots.

In traditional farming, crushed seeds were used as an insecticide and fish poison because of rotenone and other related compounds. These uses are now generally discouraged and often restricted.

The edible root is the part used in cooking, eaten raw in salads and with lime and chili, or sliced into stir-fries and spring rolls. The tender young pods are eaten in some regions, but mature pods and seeds are not.

The edible root is low in calories, high in water and fiber, and is a source of vitamin C and prebiotic fiber called inulin. There is no health benefit from eating the seeds, which have no accepted place in diet or medicine. Their significance is as a source of rotenone, which is a toxic compound, and scientific interest in them lies mainly in agriculture, pest control and toxicology.