COOPERATIVE EXTENSION. UNIVERSITY OF
CALIFORNIA
Small Farm Center Family Farm Series
ABS Extension, University of California,
Davis, CA 95616
JICAMA (YAM BEAN)
Hunter Johnson, Jr., Extension Vegetable
Specialist
University of California Riverside
Botanical Information
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.
Cultural Requirements
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.
Culinary Uses
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.
REFERENCES
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 erosus
Urban). 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.
J. Agr. Res. 74:55-64.
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).
J. Amer. Chem. Soc. 65:2259.
Norton, L. B., and R. Hansberry. 1945. Constituents
of the insecticidal resin of the yam bean (Pachyrrhizus
erosus). 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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