Agropyron cristatum, the crested wheat grass, crested wheatgrass, fairway crested wheat grass, is a species in the family Poaceae. This plant is often used as forage and erosion control. It is well known as a widespread introduced species on the prairies of the United States and Canada.
History Agropyron cristatum is one of several closely related grass species referred to as crested wheatgrass. It is unable to hybridize with its similar relatives, as it is a diploid species, whereas its closest relative, Agropyron desertorum, is a tetraploid species.Hanson, A.A. 1972. Grass varieties in the United States. USDA Agricultural Handbook No.170 It was introduced from Russia and Siberia to North America in the first half of the twentieth century, and widely used to reseed abandoned marginal cropland undergoing varying degrees of soil erosion and secondary succession. A. cristatum is very long lived, with stands often remaining productive for 30 years or more.McLean, A., and A.L. van Ryswyk. 1973. Mortality in crested wheatgrass and Russian wildrye. J. Range Manage. 26(6): 431-433.
Description Agropyron cristatum is a densely tufted grass, with culms ranging from 30 to 50 cm high at maturity. Its sheaths are scabrous or the lowest ones pubescent. Its blades are up to 8 mm wide and scabrous to pubescent above. Its spikes are flat and range from 2–7 cm long, with spikelets ranging from 8–15 mm long, being 3–5-flowered, densely crowded, and spreading to ascending. Its glumes are 4–6 mm long, awn-tipped, and its lemmas are 6–8 mm long and either awnless or awn-tipped.Agriculture Canada- Agri-Food Canada. 2001. Grass key bio 164., Lethbridge, Alberta: Lethbridge Community College. 85 p.
Agropyron cristatum is known among other grasses and wheats for its relatively high granivory. Granivory, or granivores, describe the interaction between animals and seeds. Agropyron cristatums high granivory indicates that animals feed on the seeds of the plant as their primary, or even exclusive, food source. Although this raises concerns about the plant's continued ability to reproduce if its seeds are all being consumed, the high granivory of this species does indicate that Agropyron cristatum is an important food source.Radtke TM, and Wilson SD (2015). A limited role for apparent competition via granivory in the persistence of a grassland invader. Journal of Vegetation Science 26: 995-1004.
Habitat Agropyron cristatum is best adapted to dry rangeland conditions and is most frequently found in such circumstances. It prefers from 23 to 38 cm of precipitation per year,USDA, Soil Conservation Service. 1979. Plant materials for use on surface mined lands in western United States. Denver, Colo. but can tolerate more moisture on favourable sites, extending its range into tundra and taiga conditionsMoss, E.H. 1983. Flora of Alberta (2nd edition). University of Toronto Press. Toronto, Ont and elevations up to 2000 m above sea level in the southern portions of its adapted area.Plummer, A.P., D.R. Christenson, and S.B. Monsen. 1968. Restoring big-game range in Utah. Utah Division of Fish and Game. Publication No. 68-3. It prefers well drained, deep, loamy soilsGranite Seed. 1989. 1989-90 wholesale seed catalog. Granite Seed, Lehi, Utah. 32 pp. of medium and moderately coarse texture, including Chernozemic, Solonetzic, Regosolic,Hafenrichter, A.L., J.L. Schwendiman, H.L. Harris, R.S. MacLauchlan, and H.W. Miller. 1968. Grasses and legumes for soil conservation in the Pacific northwest and great basin states. USDA Soil Conservation Service, Agriculture Handbook No. 339. Brunisolic and Luvisolic soils.Elliott, C.R., and M.E. Hiltz. 1974. Forage introductions. Northern research Group, Canada Agriculture Research Branch, Publication No. NRG 74-16. A. cristatum can tolerate salinity in the range of 5 to 15 mS/cmLaidlaw, T.F. 1977. The Camrose-Ryley project proposal (1975): a preliminary assessment of the surface reclamation potential on the Dodds-Roundhill coal field. Staff Report, Environment Conservation Authority. Edmonton, AB. and prefers moderately alkaline conditions. It has low to medium fertility requirements.Buckerfield’s Ltd. 1980. Seeds for revegetating disturbed land: descriptive manual. Buckerfield’s Seed Division. Vancouver, B.C. It will not tolerate prolonged flooding.
Agropyron cristatum is the most shade-tolerant of the crested wheatgrasses, but does best in open conditions. A. cristatum is extremely drought tolerant.Plummer, A.P., A.C. Hull, Jr., G. Stewart, and J.H. Robertson. 1955. Seeding rangelands in Utah, Nevada, southern Idaho and western Wyoming. USDA Forest Service, Agriculture Handbook No. 71. It achieves this drought tolerance by starting growth very early in the season, then going dormant from seed set until fall when it will exhibit vegetative regrowth if moisture is sufficient.
A recent study has shown that invasive populations of Agropyron cristatum have spread across the upper U.S. as well as southern Canada, and the invading Agropyron cristatum populations have been found to have a higher granivory than native grasslands and they maintain dominance even when native grassland species are reintroduced. This current study indicated that the increased granivory of Agropyron cristatum did not contribute to its competitive success. The study did show that although A. cristatum was found to have higher granivory, after 2 years the difference between A. cristatums granivory and that of native species lessens, and that there was no apparent preference among the animals for either wheat. Therefore, the factors responsible for Agropyron cristatums high granivore content are still relatively unknown.
Agropyron cristatum is very tolerant of grazing, although under dry conditions new stands should be protected from grazing for at least two years as the seedling are slow to develop. A. cristatum can be damaged by several fungi, including leaf and stripe rusts, snow mold and some arthropods including black grass bugs (Labops sp.) in pure plantings.
Due to the nature of growth in the Agropyron cristatum, it is an ideal grass type for reclamation of large areas, and even though it is ideal for drought-prone environments, it can also act as ground cover in places that may experience higher rainfall, with root systems stabilizing topsoil and limiting the impact of such components on the environment.
Uses Agropyron cristatum has been bred into many cultivars selected for attributes ranging from forage yield to drought tolerance to turf types that will exhibit more pronounced degrees of rhizomatous growth habit. It has been and continues to be, widely used in both agricultural and industrial reclamation activities.
Agropyron cristatum is known among other grasses and wheats for its relatively high granivory. Granivory describe the interaction between animals and seeds. Agropyron cristatum's high granivory indicates that animals feed on the seeds of the plant as their primary, or even exclusive, food source. Although this raises concerns about the plant's continued ability to reproduce if its seeds are all being consumed, the high granivory of this species does indicate that Agropyron cristatum is an important food source. Studies have been conducted in search of the cause of Agropyron cristatum's increased granivory, but as of yet a high relative granivory has not been proven to be a unique characteristic of A. cristatum, and could actually be attributed to factors other than the plant's genome, such as environmental conditions.
One promising factor that could lead to, and be responsible for, increased granivore in Agropyron cristatum is a certain genetic difference found on chromosome 6 of plants with a higher granivore content.Zhang J, Zhang JP, Liu WH, Han HM, Lu YQ, Yang XM, Li XQ, Li LH (2015). Introgression of Agropyron cristatum 6P chromosome segment into common wheat for enhanced thousand-grain weight and spike length. Theoretical and Applied Genetics 128: 1827-1837 Plants with a translocation on chromosome 6P yield wheat of greater weight and longer spike length than those without the mutation. Agropyron cristatum possesses higher tiller number, higher floret numbers, and greater resistance to various pathogens such as wheat rusts, powdery mildew, and barley yellow dwarf virus than many of its close wheat relatives. It has been used to cross-breed with other species of grass and wheat to transfer a greater disease resistance to them, as well as enhance their properties as a food source. This cross-breeding involves the transferring of the chromosome 6P translocation to the species it is cross-breeding with. Chromosome 6P of A. cristatum has also been proven to play an important role in regulating fertile tiller number and it possesses positive and negative regulators of tiller number.Ye XL, Lu YQ, Liu WH, Chen GY, Han HM, Zhang JP, Yang XM, Li XQ, Gao AN, Li LH (2015). The effects of chromosome 6P on fertile tiller number of wheat as revealed in wheat-Agropyron cristatum chromosome 5A/6P translocation lines. Theoretical and Applied Genetics 128: 797-811. These regulators were specifically found to be on the 6PS and 6PL chromosome arms. High floret numbers and number of kernals per spike is controlled by genes located on chromosome 6P of Agropyron cristatum.Ochoa, V; Madrid, E; Said, M; Rubiales, D; and Cabrera, A (2015). Molecular and cytogenetic characterization of a common wheat- Agropyron cristatum chromosome translocation conferring resistance to leaf rust. Euphytica 201: 89-95. Agropyron cristatum’s genes can be used to instill leaf resistance in other species of wheat. Three backcrosses between Agropyron cristatum and Aegilops tauschii produces a number stable, fertile lines of Aegilops tauschii that then has resistance to leaf rust. Also, multi-spike cultivars of A. cristatum have been found to be more stable agronomically and achieve higher yields than cultivars with large-spike type.
It is an easy grass to establish by seed, having both high germination rates and high seedling vigour.Plummer, A.P. 1977. Revegetation of disturbed intermountain area sites. Pages 302-339 IN: J.L. Thomas, ed. Reclamation and use of disturbed land in the southwest. The University of Arizona Press. Tucson, Ariz. It also establishes rapidly relative to many other grasses. Under non-irrigated conditions in low precipitation areas, Crested Wheatgrasses are consistently some of, if not the, highest yielding and persistent of domestic forage grasses. However, A. cristatum is lower yielding, although it is slightly more palatable, relative to other Crested Wheatgrasses.
Agropyron cristatum shows an immense toughness to a wide range of environmental conditions. Agropyron cristatum can be grown in cold temperatures, drought conditions, and relatively high amounts of salinity.Zhang JP, Liu WH, Han HM, Song LQ, Bai L, Gao ZH, Zhang Y, Yang XM, Li XQ, Gao AN, Li LH (2015). De novo transcriptome sequencing of Agropyron cristatum to identify available gene resources for the enhancement of wheat. Genomics 106: 129-136. It also has a resistance to barley yellow dwarf, wheat streak mosaic viruses, and leaf rust disease as well as containing high protein content.
Agropyron cristatum is a highly competitive and persistent plant in drier areas, and has a moderate ability to spread by seed. As such, its use in and adjacent to remaining natural grassland communities within its adapted areas in outside its native Eurasian distribution has come under criticism as a factor in natural grassland biodiversity loss, although the subject is still being studied.Henderson, D.C., Naeth, A.M.. 2010. Multi-scale impacts of crested wheatgrass invasion in mixed grass prairie. Biological Invasions 7(4):639-650. Retrieved 14 November 2011 from JSTOR database. One such fear is that its seedlings' emergence does not decrease under herbicide treatment.
Tenacity