ABS Extension, University of California,
Davis, CA 95616
Hunter Johnson, Jr., Extension Vegetable Specialist
University of California Riverside
Jicama (pronounced he'-cama) is a tropical legume which produces an edible fleshy taproot. The above-ground part of the plant is a vigorous spreading prostrate vine which reaches several feet in diameter. Flowers, either blue or white, and pods similar to lima beans are produced on fully developed plants. There are several species of jicama, but the one found in our markets is Pachyrrizus erosus. There are two cultivated forms P. erosus: jicama de agua and jicama de leche. The latter has an elongated root and milky juice. The agua form has a top-shaped to oblate root, a translucent juice, and is the preferred form for market.
A Crop for California?
All of the jicama found in our markets is produced in Mexico. There has been recurrent interest in producing this crop in California, but only undocumented reports of successes. The known efforts to grow jicama have resulted in luxurious vine growth with prolific flowering and pod production but with low quality fibrous taproots. A long, warm growing season under relatively short day length is required to initiate good quality fleshy root development. Recent research (Cotter and Gomez) confirms this and suggests that sufficient variability may exist within the species to allow selection for longer day types. Since the temperature and day length conditions required to mature good quality roots of currently available cultivars do not exist in the United States (except perhaps in the south of Florida), it is unlikely that current cultivars of jicama can be grown successfully in this country. Any plantings which may have produced good roots in past years in California very likely occurred under unusually warm October and November conditions, a weather phenomenon which is rare even in the southern part of the state.
Jicama is propagated by seed. The seeds are squarish in shape, brown or tan in color, with the general characteristics of other bean seed. Sandy loam soil with good drainage is the best choice to obtain smooth roots. Rows should be two to three feet apart with plants eight to 10 inches apart in the row. Information on fertilizer requirements is limited, but one source suggests 1,500 pounds per acre of 6-6-12. In the tropics, three to six months are required to develop marketable roots, depending on temperature at the growing location. The literature on jicama indicates that, for best root production, flowers should be removed at an early stage. It is stated that flower removal causes the root to expand in diameter. Yields are in the range of five to seven tons per acre.
Jicama is most commonly eaten in the fresh form. After peeling to remove the brown fibrous outer tissue, the crisp white fleshy portion can be sliced, diced, or cut into strips for use as a garnish, in salads, or with dips. It is frequently served as a snack sprinkled with lime or lemon juice and a dash of chili powder. Jicama remains crisp after boiling and serves as a textural substitute for water chestnuts. Jicama is similar to white potatoes in food value, but with slightly lower total food energy (calories). In the tropical production areas, the immature pods are sometimes cooked and eaten, but mature pods are said to be toxic. Mature seeds contain a fairly high content of rotenone, and at one time, commercial culture of jicama was considered as a source of this insecticide.
Clausen, R. T. 1944. A botanical study of the yam beans (Pachyrrhizus). Cornell University Agricultural Experiment Station, Memoir 264.
Cotter, D. J., and R. E. Gomez 1979. Daylength effect on root development of jicama (Pachyrrhizus erosusUrban). HortSci. 14(6):733-734.
Hansberry, R., R. T. Clausen, and L. B. Norton. 1947. Variations in the chemical composition and insecticidal properties of the yam bean.
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Herklots, G.A.C. 1972. Vegetables in South-East Asia. George Allen and Unwin Ltd., London. pp. 449-452.
Miller, C. D., and B. Branthoover. 1957. Nutritive values of some Hawaii foods. Hawaii Agr. Exp. Sta. Circ. 52: p. 16.
Norton, L. B. 1943. Rotenone in the yam bean (Pachyrrhizus erosus).
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Norton, L. B., and R. Hansberry. 1945. Constituents of the insecticidal resin of the yam bean (Pachyrrhizuserosus). Amer. Chem. Soc. J. 67:1609-1614.
Porterfield, W. M. 1939. The yam bean as a source of food in China. New York Bot. Gard. J. 40:107-108.
__________________________. 1951. The principal Chinese vegetable foods and food plants of Chinatown markets. Econ. Bot. 5(l):12.
Schroeder, C. A. 1967. The jicama, a rootcrop from Mexico. Proc. Trop. Reg., Amer. Soc. Hort. Sco. 11:65-71.
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