Zizania aquatica L.

Poaceae
Wild rice

Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.

Uses
Folk Medicine
Chemistry
Description
Germplasm
Distribution
Ecology
Cultivation
Harvesting
Yields and Economics
Energy
Biotic Factors
References

Uses

Wild rice was a staple food of American Indians and is a food for wild birds and waterfowl, especially mallard, bobolink, blackbirds, and Carolina rail. It has been a luxury food to compliment wild game dishes for many years when only harvested from lakes and rivers, but during the last fifteen years, since its cultivation, wild rice has become more plentiful and can be found in many stores. Wild rice has potential in utilizing current waste swamplands in northern climates. Compared with other cereals, it is high in protein and low in fat (see table). One of the most famous Indian dishes was tassimanonny; wild rice, corn, and fish boiled together. Perhaps its greatest fame is as side dish with (or inside) wild gamebirds, ducks, pheasants, quail, and turkeys for example. Aquatic birds readily stuff themselves with wild rice, which may constitute more than 10% of the stomach contents of black ducks, mallards, and woodducks (Steeves, 1952). Today, because of its increased abundance, wild rice is used in a variety of ways. It is used in place of potatoes, either alone or mixed with rice, and in soups and salads, even deserts.

Folk Medicine

Reported to be diuretic and refrigerant, Zizania aquatica is a folk remedy for burns, heart ailments, hepatosis, nephrosis, pulmonosis, and stomach ailments (Duke and Wain, 1981).

Chemistry

Proximate analyses by Wang et al. (1978) on a zero moisture basis 15.2–17.0% protein, 1.2–1.8% fat, 1.8–2.0% ash, 1.2–2.0% fiber, and 77.7–80.1% carbohydrate. The proteins were rich in glutelins and essential amino acids, especially lysine and methionine. Miller's (1958) analyses differs slightly, 13.8–16.3% protein (ave. of 9 = 15.1), 0.5–1.0% fat (ave. 0.7), 0.7–1.2% crude fiber (ave. 1–0), 1.3–1.7% ash (ave. 1.5), and 80.5–83.5% N-free extract (ave. 81.7). Studying the starch, Lorenz (1981) reported that wild rice contains only 2% amylose (cf 25% for wheat). Withycombe et al. (1978) identified 112 volatile components.

Description

Annual, robust, erect, aquatic or paludal, monoecious grass; culms tall, erect, to 3 m tall, hollow with transverse walls; leaves flat, to 1 m long, 4 cm wide, leaf-markings purple, with thick midrib often nearer one margin than the other; flowers cross-fertilized and wind-pollinated, in large, open, terminal panicles to 40 cm long; pistillate flowers enclosed by two glumes, the outer one larger, awned and toward the axis, clustered.on upper erect portion of panicle, opening before male flowers which are on lower portion; staminate flowers on spreading branches consisting of two glumes enveloping six bright yellow stamens; male and female flowers range from white to purple; spikelets one-flowered, with long stiff twisted barbed awns; kernels (seed) closely adhering to thin brown hull, shallow-grooved the entire length of one surface, long, nearly cylindrical, 1.2–1.9 cm long, about 0.7–1 mm wide, purplish-black when ripe. Roots slender, fibrous, penetrating shallowly; some adventitious roots present.

Germplasm

Terrell and Batra recognize three N. American species of Zizania, southern wild rice (Z. aquatica) on the Atlantic Coastal plain from Central Florida to ne N. America, northern wild rice (Z. palustris) ranges from ne N. America west through the Great Lakes to southcentral Canada, and the endangered Texas wild rice, (Z. texana) species known only from Hays County, Texas. Z. texana is a perennial while the other two are annuals. Reported from the North American Center of Diversity, wild rice, or cvs thereof, is reported to tolerate flooding, low temperatures (28°F), some salt, and, of course, waterlogging (Duke, 1978). Species extremely variable in all features, some differences due to soil and climatic conditions. Mature plants in Eastern Canada vary from 15–25 cm tall, at most 90 cm, with only 1–1.3 m above water, while in colonies further south may be 4 m tall, with 2–2.3 m above water. Panicles may vary from 50 cm in length to 60 cm or more, with the pistillate having from 3–7 seeds northward to 17–27 seed southward. Mature seed from wild types shatter easily, while cultivated types have been selected for some shattering resistance. Both types are susceptible to diseases, especially brown spot, and to insects.

Distribution

Native to North America from the northern end of Lake Winnipeg southward to Gulf of Mexico, and eastward to the Atlantic Coast, being more generally found in Minnesota and in southern Manitoba and Ontario, Canada. A related species has been reported from Japan, Taiwan, China, and USSR. Most grass taxonomists regard this species as distinct (Z. latifolia). It is a perennial.

Ecology

Ranging from Cool Temperate Dry to Warm Temperate Moist Forest Life Zones, wild rice is reported to tolerate annual precipitation of 3.5 to 11.6 dm (mean of 6 cases = 8.0), annual temperature of 6.9 to 12.5°C (mean of 6 cases = 8.6), and pH of 4.9 to 8.5 (mean of 5 cases = 6.1) (Duke, 1978; Steeves, 1952). It is completely absent from strongly alkaline waters (Steeves, 1952). Stagnant water is unsuited to the plant. Although the current must not be perceptible, a constant change of water is desirable. Generally, the best wild rice stands are found in water with <10 ppm sulfate, but wild rice has been grown experimentally in water with 220 ppm sulfate (Vicaria and Halstead, 1968). Fresh water plant, not growing successfully in water with a salty taste. In eastern and southeastern United States thriving in brackish water in low marshes bordering tidal rivers, and in no more than 0.6 m of water, and where the annual change of water level is not more than 0.6–0.9 m of water. Grows wild in shallow freshwater lakes and on margins of lakes and streams, often covering vast areas, especially in northern United States and southern Canada. Wild rice requires slow-flowing water through the rice bed or field, with depth of water from 15 cm to 1.6 m; with constant or slightly declining water levels through the growing season, whereas if levels rise, the boyant leaves and stems may pull roots out of loose muck; best stands in water with alkalinity of 40–200 ppm; pH 5.9 to near 7.0, with best growth at pH 6.8–8.8; sulfate-iron concentration below 10 ppm; with low percent of available potash and phosphate and high organic content of soil.

Cultivation

Wild rice stands in lakes and rivers reseed themselves and can reproduce indefinitely if water levels do not change significantly during the year over a number of years. New lakes or certain areas of a river can be planted with seed or young plants. Seed intended for germination should be stored over winter in aerated water that is cold (+2°C). It should not be frozen in ice. Seed is shipped in a (30% moisture) dry state during the first 2 weeks after harvest with very little loss of viability when packed in dry instead of moist sphagnum moss. Seed viability is lost if the seed is allowed to dry below 28% moisture. For late fall, winter, or spring deliveries, seed must be transported in wet state and in cool (+4°C) temperatures, so seed won't sprout. Seed sown in spring, from boat on rising tide when water is 2.5 cm deep., Good ripe seed is brown in color and will sink when sown. Scatter evenly at rate of 1 handful to 2 sq. meters, sowing more heavily if the locality is new. Or, transplant from beds submerged in 16 cm water when 30–37 cm tall, planting into 20 cm or more of water, about 0.3 cm apart. Cultivation of wild rice as a field crop began in 1950 but substantial acreage was not cultivated until the late 1960's. In 1982, there were 7,600 ha grown in Minnesota, Wisconsin, Idaho, and California. The major portion (6,400 ha) was grown in diked fields that are flooded in the spring and drained before harvest with combines. The types being grown have some shattering resistance, and can be harvested once like other small grains.

Harvesting

Lake and river stands are repeatedly harvested because the seed does not mature evenly and readily shatters. Sufficient seed is always lost to reseed adequately. Harvest is only 30–50% efficient due to shattering. Sometimes only part of crop is harvested, leaving ample seed. Wild rice is harvested from boats (usually canoes) after 4 1/2 months of growth. Stalks are pulled over into the boat with one stick and gently beaten with another stick to release only the mature kernels. Harvesting period may extend for several weeks. Some harvesting machines are used in which a reel-type beater is attached to the front end of a flat boat and moved through the rice field. Machines can only be used in lakes and rivers in Canada. Laws in Minnesota only allow harvest by boat. Harvested seed is taken ashore, and immediately transported to processing plants for preliminary curing in windrows. The windrows are turned and watered daily to prevent heating. After curing, the grain is parched in a rotating drum. Heat is applied to the drums and the grain dried to about 7% moisture. The hulls are removed from the warm grain by a huller which consists of two rubber rollers; one traveling at a slightly higher speed than the other. The hulls are removed by aspiration and then the grain is packaged for market. Processed seed will not germinate and can't be used as seed for planting. Unprocessed seed to be stored for germination may be put in perforated galvanized cans and the cans put in a stream or field covered by at least 60 cm of water. It will require no more attention until planting time the next season. The seed can also be stored in water in a cooler kept at 2°C. The water needs to be changed every month.

Yields and Economics

Grain (35% moisture) yields vary from 90 to 300 kg/ha from lake or river stands. From 120,000 to 400,000 kg of wild rice are harvested for food in the northcentral United States and in Canada annually from lakes and rivers, depending upon climatic conditions. Wild rice stands on Indian reservations can only be harvested by Indians in Minnesota; other stands can be harvested by any resident, if they have a license. Another 1,220,000 kg of wild rice is produced in cultivated fields; Minnesota produces about 3/4 of this. The total crop in Minnesota is estimated to bring $10,000,000.

Energy

Grava and Raisanen (1978) reported that one plant produced 30.2 g of total above ground dry matter and Terrell (personal communication) said, "wild rice is one of the largest grasses I know outside the bamboo" (one ha produced 11,800 kg DM). Specimens along the Patuxent River in Maryland attain 4 m in height. Since it is annual, it could be harvested, with difficulty, after seed harvest with little or no damage to subsequent crops.

Biotic Factors

Redwing blackbirds (Agelaius phoeniceus) frequently strip entire stands in the 'milk' stage. They may be repelled with metallic streamers. Heavy winds and hailstones cause damage and reduce yields. The following fungi have been reported as causing diseases to wild rice: Bipolaris oryzae, Cercospora zizaniae, Claviceps purpurea, C. zizaniae. Diplodia oryzae, Doassansia zizaniae, Entyloma lineatum, E. pamelii, E. penisulae, Mycospherella zizaniae, Ophiolobus orysinus, Sclerotium zizaniae, Sphaerella zizaniae. Puccinia zizaniae, Uromyces coronatus, Ustilago esculenta. Wild rice is also attacked by the following nematodes: Dolichodorus sp., Hirschmanniella gracilis, Radopholus gracilis, Xiphinema americanum. Alisma triviale, the waterplantain, at densities of 43 plants/m², reduced wild rice yields >90% in cultivated fields (Ransom and Oelke, 1982).

References

Duke, J.A. 1978. The quest for tolerant germplasm. p. 1–61. In: ASA Special Symposium 32, Crop tolerance to suboptimal land conditions. Am. Soc. Agron. Madison, WI.
Duke, J.A. and Wain, K.K. 1981. Medicinal plants of the world. Computer index with more than 85,000 entries. 3 vols.
Grava, J. and Raisanen, K.A. 1978. Growth and nutrient accumulation and distribution in wild rice. Agronomy J. 70:1077–1081.
Lorenz, K. 1981. The starch of wild rice (Zizania aquatica). Starch/Staerke 33(3):73–76.
Miller, D.F. 1958. Composition of cereal grains and forages. National Academy of Sciences, National Research Council, Washington, DC. Publ. 585.
Ransom, J.K. and Oelke, E.A. 1982. Common waterplantain (Alisma triviale) interference with wild rice (Zizania palustris). Weed Sci. 30(1):10–14.
Steeves, T.A. 1952. Wild rice—Indian food and modern delicacy. Econ. Bot. 6(2):107–142.
Terrell, E.E. and Batra, L.R. 1982. Zizania latifolia and Ustilago esculenta, a grass-fungus association. Econ. Bot. 36(3):274–283.
Vicaria, B.T. and Halstead, E.H. 1968. Progress report on wild rice research. Dept. of Soil Science, University of Saskatchewan, Saskatoon, Canada.
Wang, H.L., Swain, E.W., Hesseltine, C.W., and Gumbmann, M.R. 1978. Protein quality of wild rice. J. Ag. & Food Chem. 26(2):309–312.
Withycombe, D.A., Lindsay, R.C., and Stuiber, D.A. 1978. Isolation and identification of volatile components from wild rice grain (Zizania aquatics). J. Ag. & Food Chem. 26(4):816–822.

Complete list of references for Duke, Handbook of Energy Crops

WILD RICE
Whiteman say to the Redman, "Is this the Promised Land?
Wild rice in paradise and turkey in the hand!"
Whiteman say to the Redman, "Just look at what you have got,
Wild rice and wild thyme and turkey in the pot!"
Whiteman say to the Redman, "I think I envy you.
Wild rice and artichokes and groundnuts in the stew.
From seeds you haven't planted, you harvest twenty more.
While we have sowed our wild oats, and don't harvest anymore.
Redman say to the Whiteman, "Do you really have to push
Redman and greener land and turkey in the bush.
You came and showed your might man, just look what you have done.
The wild rice grows leaner, and the turkey's on the run.

Last update Friday, January 9, 1998 by aw