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Wagoner, P., and A. Schauer. 1990. Intermediate wheatgrass as a perennial grain crop. p. 143-145. In: J. Janick and J.E. Simon (eds.), Advances in new crops. Timber Press, Portland, OR.

Intermediate Wheatgrass as a Perennial Grain Crop

Peggy Wagoner and Anne Schauer

  1. INTRODUCTION
  2. RESEARCH APPROACH
  3. GERMPLASM EVALUATION
  4. DEVELOPMENT OF CULTURAL PRACTICES
  5. NUTRITIONAL ANALYSIS AND FOOD USE EVALUATIONS
  6. SUMMARY
  7. REFERENCES

INTRODUCTION

Present grain crop production is based entirely upon annuals. Given the proper conditions, these crops can produce spectacular yields. However, annual grains are not necessarily the best crop for all situations. On hilly or otherwise marginal land, annual crop production can lead to severe soil erosion. Such erosion not only costs the farmer in terms of lost nutrients, but it also costs society in terms of siltation and degradation of water resources. In addition to being environmentally unsound, annual crop production on such land is often economically impractical. Alternative crops must be developed for use on land that can not sustain annual crop production. The development of perennial grasses as grains could provide such an alternative.

Perennial grains can provide advantages over annuals including lower production inputs as well as year round soil protection. Mechanical field operations in a perennial grain system will be greatly reduced because the soil will not be re-worked each year, thus saving on fuel and labor costs. Seed purchases and planting would be done every five to ten years rather than every year as with annual grains. Where legumes are included with plantings of perennial grains, the need for commercial fertilizers could be reduced. A perennial grain/legume mixture could be considered analogous to a grass/legume pasture. However, instead of the primary harvest product being the hay as in a pasture, the primary harvest product will be the grain from the perennial grass. In some areas, the perennial grain/legume fields can be used for hay production or grazed as pastures after the yearly seed harvest. In addition, the use of perennial grains could rebuild soil structure through increased soil organic matter, water infiltration and biological activity in the soil. Because the soil will have vegetative cover during the entire year, wildlife such as game birds and mammals could also benefit.

RESEARCH APPROACH

In 1983, the Rodale Research Center (RRC) in eastern Pennsylvania initiated a long term research project to investigate the potential of developing a perennial grain cropping system. This project is patterned after the ideas proposed by Dr. Wes Jackson (1985) who initiated the concept of producing grains from herbaceous perennial plants.

Close to 100 species of perennial grasses were evaluated at the RRC in order to identify those with good potential for development into perennial grain crops. Selection of the most promising species was based on the following criteria (Wagoner 1988):

Based on these selection criteria, intermediate wheatgrass, Thinopyrum intermedium (Host) [syn. Agropyron intermedium (Host) Beauvois], a perennial relative of wheat, appears to have good potential for development into a perennial grain crop. This native of southwestern Asia and the Mediterranean region produces seeds which average 5.3 g/1000 seeds (Schulz-Schaeffer and Haller 1987). Seeds can be mechanically harvested and threshed using commercially available equipment. Nutritionally, intermediate wheatgrass is very similar to wheat with slightly higher protein levels (Becker et al. 1986). The grain can be ground into flour for use in flavorful baked products such as muffins and breads or cooked as a whole grain, like rice.

GERMPLASM EVALUATION

Intermediate wheatgrass is a cool season, rhizomatous perennial which is used extensively for pasture, hay and soil erosion control in the Great Plains and intermountain West (Hanson 1972). Since 1986, a total of 250 accessions of intermediate wheatgrass have been acquired by the RRC from a variety of sources. Half of these were obtained from the USDA Plant Introduction Office in Pullman, Washington. These PI accessions were originally collected in the Soviet Union, Iran, Turkey and other areas of the eastern Mediterranean region. An additional 100 accessions were collected as single plant selections from breeding lines growing in field plots at the Northern Great Plains Research Center in Mandan, North Dakota. Several accessions have been obtained directly from the Soviet Union through the N.I. Vavilov Institute of Plant Industry. Commercially available varieties of intermediate wheatgrass have also been obtained from seed companies in the U.S.

This germplasm is being tested in small plots at the RRC to determine seed production capabilities. Seed yield components are being evaluated for each accession in order to select high yielding lines for future breeding programs. Characteristics being studied include seed size, measured as weight of 100 seeds, number of fertile florets/seedhead, a measure of seedhead fertility and fertile tillers/plant. Both seed size and fertility are highly heritable characteristics in intermediate wheatgrass (Slinkard 1965, Trupp 1965). Therefore, clonal selection based on these two yield components should be effective in increasing seed yield.

Seedhead fertility was evaluated in 150 accessions during the 1988 growing season using the seedset rating method described by Trupp and Slinkard (1965). Results of seedset ratings conducted at the RRC range from 8% to 52% for the germplasm tested thus far. Seed size evaluations conducted at the RRC in 1987 and 1988 indicate that the germplasm ranges from 3.6 g to 7.2 g/1000 seeds. This initial information indicates that there is sufficient variation in the germplasm to make selections for higher yielding lines.

Characteristics other than fertility and seed size are being evaluated for each accession. These include number of fertile tillers, synchrony of seed maturity, retention of spikelets on the rachis (resistance to shattering) and ease of threshing seeds from the glumes. General growth and vigor parameters such as resistance to lodging, vigor of spring and fall regrowth, date of 50% anthesis and presence of diseases such as rust, ergot or Septoria glume blotch are also being evaluated. Each accession will be evaluated for all of these characteristics over the next 3 to 5 years as a prelude to crop improvement programs.

DEVELOPMENT OF CULTURAL PRACTICES

Cultural techniques are being examined at the RRC to develop successful low input methods of producing perennial grains on a commercial scale. Information developed by the perennial grass seed industry is being adapted to the production of intermediate wheatgrass grain. Beginning in 1984, plots of 'Oahe' intermediate wheatgrass were established at the RRC using a John Deere grain drill. Various planting dates and seeding rates have been tested. Best results are obtained when intermediate wheatgrass is interplanted with a legume such as white clover in late August (Wagoner and Schauer 1988). Management practices which are being studied include the use of manure and companion planted legumes for fertility maintenance as well as the use of fire, mowing and grazing to maintain plant vigor (Wagoner and Schauer 1988).

Grain is harvested from experimental plots each August using a Massey Harris small grain combine. Yearly grain yields range from 100 to 500 kg/ha. While these yields are low compared to annual grains such as wheat, grain yields from perennial grasses are never expected to be as high as those from annual grains because part of the perennial plant's energy goes into production of roots rather than seed. Nevertheless, a perennial grain cropping system which is well adapted to the environment in which it is growing can be economically viable. The reduced costs of inputs will make it possible to obtain a net profit at lower yield levels (Watt 1989). Perennial grains could be grown on marginal lands that can not support annual crops. There is already legislation which has taken erodible land out of production. This research is aimed at providing an alternative use for that type of land. Perennial grains could, in the future, provide farmers with an economic return from land that may otherwise remain idle.

NUTRITIONAL ANALYSIS AND FOOD USE EVALUATIONS

Nutritional and food use evaluations of intermediate wheatgrass grain are being conducted in collaboration with the USDA Western Regional Research Center (WRRC) in Albany, California. The nutritional qualities of this perennial grain are similar to wheat and rye. Compared to wheat, intermediate wheatgrass has a slightly higher protein level with a higher content of the sulfur containing amino acids, methionine and cysteine. This could be valuable for complementation with legumes in food applications (Becker et al. 1986). Flavor qualities of intermediate wheatgrass grain are also good. At the 100%, 66% and 33% wheat flour replacement levels, whole flour from intermediate wheatgrass grain performed well in baked products such as muffins and rolls. Wheat flour-perennial grain flour blends were preferred (sweet/nutty) over the wheat flour control (Burwell 1984).

Farinograph tests of whole grain flours made from several different cultivars of intermediate wheatgrass were conducted by Tracy Bergman at the WRRC. The performance of 'Luna' was very similar to that of a high quality dough forming wheat. Interestingly, 'Oahe' did not compare as favorably. This demonstrates that th e re may be sufficient variability among the intermediate wheatgrasses to select and develop lines for different culinary purposes as in wheat.

SUMMARY

Perennial grain cropping systems could provide many environmental benefits through the reduction of soil erosion as well as the reduction of inputs necessary to produce grain crops. The development of such perennial grain systems is a long term prospect. It will require research in a range of disciplines including agronomy, plant breeding, food use evaluation and market development. This process is not simply the development of a new crop, it is the development of a whole new approach to grain production on erodible land based on perennial rather than annual herbaceous plants. The development of perennial grains such as intermediate wheatgrass is an important step toward the regeneration of our soil and water resources.

REFERENCES

Last update February 14, 1997 by aw