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Wild Triga
Intermediate Wheatgrass

Contributor: Peggy Wagoner, Rodale Institute Research Center, Kutztown, PA

Copyright © 1995. All Rights Reserved. Quotation from this document should cite and acknowledge the contributor.


  1. Common Names
  2. Scientific Names
  3. Uses
  4. Origin
  5. Crop Status
    1. GRAS Status
    2. Toxicities
    3. Traditional Uses
  6. Botany
    1. Taxonomy
  7. Crop Culture
    1. Ecology
    2. Cultivars
    3. Production Practices
    4. Harvesting Wild Triga
  8. Germplasm
    1. Collections
    2. Commercial Seed Sources
    3. Evaluations and Varietal Development
  9. Key References
  10. Selected Experts

Common Names

English: wild triga, intermediate wheatgrass
Term used to refer to this crop as a perennial grain: Wild Triga
Term used to refer to this crop as a forage: intermediate wheatgrass

Scientific Names

Species: Thinopyrum intermedium (Host) Barkworth & D.R. Dewey
Agropyron intermedium (Host) Beauvois
Elytrigia intermedia (Host) Nevski
Elymus hispidus (Opiz) Meldris
Agropyron glaucum (Desf. ex DC.) Roemer & Schultes
Family: Graminaceae
Tribe: Triticeae

Uses

Wild Triga is unique in that it is a perennial grain crop, unlike all of our other grains which are annuals. Seeds are used as a grain for human consumption. Grain can be ground into flour to make baked product or cooked whole like rice. The grain has a sweet mild nutty flavor. Grain has higher levels of protein (20.8%), fat (3.21%) and ash (2.64%) than wheat. The protein is nutritionally limiting in lysine as is wheat, but Wild Triga has higher levels than wheat of all other essential amino acids. In samples of intermediate wheatgrass grain (Wild Triga) tested by USDA, no functional gluten was found. However no tests have been conducted to determine if individuals with wheat or gluten allergies can tolerate Wild Triga grain. Intermediate wheatgrass is closely related to wheat and may cause similar problems.

Herbage of intermediate wheatgrass is used extensively as an introduced cool-season forage in the USA and Canada and as a native forage in temperate regions of the Old World.

Intermediate wheatgrass is also used as a reclamation grass for mine sites and planted along roadways and airport landing strips for erosion control.

Origin

Old World from southern Europe through the Middle East and central Asia to western Pakistan.

Crop Status

Wild Triga grain is available commercially from Den Besten Seeds, Inc., Box 896 Platt SD.

Intermediate wheatgrass seed is grown in the northern Great Plains and intermountain western USA primarily to supply the seed industry for planting pastures and hay crops. During the seed conditioning process, some intermediate wheatgrass seeds lose their hulls, producing naked hull-less grain. The hull-less seeds tend to lose viability more quickly and are therefore not sold for planting hay and forage crops. Previously, this naked grain represented a loss to the seed industry as it was not sold for planting. This grain is now being sold as Wild Triga, the first commercially available perennial grain.

GRAS Status

Wild Triga is generally recognized as safe as a grain relative of wheat.

Toxicities

Levels of anti-nutritive substances such as tannins or trypsin inhibitors, are similar to those found in wheat. None have been found at harmful levels.

Individuals with wheat or gluten allergies should use caution with Wild Triga grain as it is a close relative of wheat.

Traditional Uses

In addition to being an important cool-season forage, wild triga grain may have been consumed in Turkey, Armenia and the Caucasus mountains during Byzantine times. More recently, in the former Soviet Union, efforts were made to develop perennial wheat through wide hybridization of wheat with intermediate wheatgrass. Problems with sterility and genetic incompatibility were encountered. Instead, intermediate wheatgrass has since proven useful as a source of genes for disease resistance which have been transferred to annual wheat. In the last several years, there has been renewed interest in wheat x intermediate wheatgrass hybrids to develop a perennial grain by Peters Seed and Research in Oregon.

Botany

Taxonomy

Intermediate wheatgrass (Wild Triga) is a perennial cool-season rhizomatous grass (family Gramineae). As a member of the tribe Triticeae, intermediate wheatgrass is related to important annual grains such as wheat, rye and barley as well as 250 species of perennial grasses, many of which are important forage grasses.

The taxonomic classification of intermediate wheatgrass has been unsettled for some years. Until recently, North American botanists have classified intermediate wheatgrass as Agropyron intermedium (Host) Beauvois. A close relative, pubescent wheatgrass, has been classified as Agropyron intermedium var. trichophorum. Pubescent wheatgrass shows its pubescence on the seed heads and leaves in contrast to intermediate wheatgrass which is glabrous. Both are considered part of the intermediate wheatgrass species complex because they coexist in Old World habitats and are freely interfertile.

Dewey (1984) proposed a new taxonomic classification based upon cytogenic information, phylogeny and biological relationships. Under this classification, both intermediate and pubescent wheatgrass are Thinopyrum intermedium.

Crop Culture

Ecology

In addition to its area of origin in the Old World, intermediate wheatgrass is widely adapted to inland sites in the temperate zone. In North America, it grows throughout the intermountain west and the Great Plains from the Canadian prairie in Saskatchewan south into New Mexico. It also grows in higher rainfall areas east of the Great Plains to Pennsylvania and South Carolina. It requires a period of vernalization in order to produce grain.

Differences in adaptation between pubescent and glabrous forms have been noted in the USA. The pubescent form appears to be better adapted to areas of low annual precipitation (200-400 mm), droughty soils and slightly saline soils. The glabrous form is better adapted to area with 400 mm or more annual precipitation and grows well even in relatively high rainfall areas of the eastern USA. Intermediate wheatgrass grows from sea level up to 3000 m elevation.

Cultivars

Quite a number of cultivars for use as forage grasses have been released since 1945. The most popular include: Oahe, Luna, Chief, Greenar, Reliant, Tegmar, Greenleaf and Topar.

Seeds from any of these cultivars can be used for grain, but 'Oahe' and 'Luna' have been the cultivars most often used due to their good seed yield and quality and the fact that they lose their hulls somewhat easily as compared to some of the other cultivars.

Production Practices

Cultural techniques to produce intermediate wheatgrass seed have been developed by the forage seed industry. These techniques can be modified for the production of grain. Since intermediate wheatgrass is a perennial, it can be planted on hilly land that should not be planted to continuous annual crop production. It can be grown in contour strip alternating with annual crops and rotated with annuals on a five to seven year basis. The strips containing the perennial grain will build soil and catch any eroding soil coming from the areas planted to annuals.

The best stands of Wild Triga (intermediate wheatgrass) are established when seeded into a weed free seed bed. With sufficient moisture, plants germinate quickly, within 3-4 days. The optimum planting date is late summer when warm-season weeds are not competitive. Seeding rates are between 7 and 15 pounds/acre with rows spaced 7 to 10 inches apart. Seeds within rows should be spaced 1-2 inches apart. The lighter rate should be used in drier climates and the heavier seeding rate in wetter environments.

This perennial grain will germinate and grow during the autumn, putting much of its energy into the development of roots. During the winter it goes dormant and begins regrowing vigorously in the spring. Plants will begin sending up grain heads in June and the grain will be ready for harvest in August.

Harvesting Wild Triga

Wild Triga will produce its first grain crop about 11 months after planting. When the grain heads begin to turn a straw color, the seeds are maturing. Wild Triga grain can be direct harvested with a combine or it can be swathed and combine harvested after drying. The techniques to use will depend upon the location and weather patterns. Swathing should be done when heads are beginning to show a slight amount of drying (a tan color). It is important that there be no rain during the period immediately after swathing and before harvesting the swathed material.

Direct combining should be done when the heads are completely dry and the stalks are showing the dry tan color as well. Some grain may shatter before this condition is attained. The maximum recovery of grain will usually be achieved by waiting for the heads and stalks to dry. It is necessary to adjust the combine settings to accomodate the smaller sized grain of Wild Triga.

Most of the grain will have the hulls still attached after harvesting. Dehulling can be accomplished with any piece of equipment that will rub the grain vigorously. A brush machine in which brushes rotate rapidly inside a cylindrical screen is an effective dehuller.

Yields of Wild Triga are lower than those of annual grains because part of the plant's energy goes to root production to sustain the plant over winter. However, since production costs are lower, net profits are possible at lower yield levels in this perennial as compared to annual grains. If yields of 500-600 lbs/A can be maintained over the course of four to six years, the breakeven price of Wild Triga would be 6 cents/pound. Yields of 500-600 lb/A are typical in the first year of production. Grain yields decline in subsequent years. Appropriate management techniques can help reduce the yield decline. Grazing intermediate wheatgrass stands in the fall after grain harvest can rejuvenate stands by adding nitrogen through manure and provide a secondary harvest product, the forage. Alternatively, Wild Triga can be chiseled to rejuvenate sod-bound stands, having a dramatic positive effect on yields without jeopardizing the stand or subjecting it to erosion.

Germplasm

Collections

Western Regional Plant Introduction Office
Washington State University, Pullman, WA 99164
U.S. Living Collection of Perennial Triticeae Grasses
Utah State University, Logan UT 84322

Commercial Seed Sources

Den Besten Seeds, Inc.
Box 896, Platt, SD 57369
Southwest Seed Co., Inc.
13260 RD 29, Dolores, CO 81323

Evaluations and Varietal Development

More than 400 germplasm lines of intermediate wheatgrass were evaluated at the Rodale Institute Research Center between 1987 and 1994 to determine growth and grain yield characteristics. Selections of the most promising lines are being used in several cycles of a recurrent phenotypic selection program in collaboration with NRCS (former SCS) in Big Flats NY to develop higher yielding well adapted varieties of Wild Triga.

Key References

Selected Experts

Lowell Den Besten, Den Besten Seeds, Inc. Box 896, Platt SD 57369. Tel. (605) 337-3318.

Tim Peters, Peters Seed and Research, 407 Maranatha Lane, Myrtle Creek, OR 97457

Martin van der Grinten, Natural Resources Conservation Service, Big Flats Plant Materials Center, Big Flats, NY 14830. Tel (607) 562-8404

Peggy Wagoner, Rodale Institute Research Center, 611 Siegfriedale Road, Kutztown, PA 19530 Tel. (610) 683-1442; Fax (610) 683-8548

Contributor: Peggy Wagoner, Rodale Institute Research Center, Kutztown, PA

Copyright © 1995. All Rights Reserved. Quotation from this document should cite and acknowledge the contributor.


Last update Tuesday, February 24, 1998 by aw