Wheatgrass Complex Research Articles

Breeding of the Crested Wheatgrass Complex (Agropyron spp.) for North American Temperate Rangeland Agriculture and Conservation

Species from the crested wheatgrass (Agropyron spp.) complex have been widely used for revegetation and grazing on North American rangelands for over 100 years. Focused crested wheatgrass breeding has been ongoing since the 1920s. These efforts resulted in the development of 18 cultivars adapted to western USA and Canadian growing conditions. These cultivars establish rapidly, persist, and provide soil stabilization and a reliable feed source for domestic livestock and wildlife. To address ecological concerns and increase rangeland agriculture efficiency, crested wheatgrass breeding requires new emphases and techniques. This review covers the history of crested wheatgrass breeding and genetics in North America and discusses emerging methods and practices for improvement in the future.

An overview: Systematic relationships of Elymus and Roegneria (Poaceae)

Elymus L. sensu Löve and Dewey is currently the most diverse and ubiquitous genus within the perennial Triticeae. As originally conceived by Dewey and Löve, Elymus contained species that were caespitose, small anthered, self-pollinating and contained the SH genomes. Chromosome pairing data in intergenomic hybrids has demonstrated that species in Elymus are heterogenomic with the SH, SY, SHY, and SYP genome combinations. The S, H, Y, and P genomes are distinct; however, low levels of homology apparently exist between the S and Y, and the S and P genomes. Under the genomic system of classification, each genome combination represents a new genus, thus splitting Elymus into four genera. Morphologically, the genomic groups SH, SY, and SHY are not distinct. Variation in leaf epidermal characters does not justify splitting of Elymus. Intergenomic hybrids between the three genomic groups are sterile; however, in nature natural hybridization between and within genomic groups occurs, creating character overlap which presents identification problems. Those species that are treated in Roegneria C. Koch section Paragropyrum, Elymus sections Hyalolepis and Goulardia, and Kengyilia gobicola comprise the S, Y, and P genomes and are morphologically similar to the crested wheatgrass complex (Agropyron Gaertn.) and may warrant generic rank

An overview: Systematic relationships of Elymus and Roegneria (Poaceae)

Elymus L. sensu Löve and Dewey is currently the most diverse and ubiquitous genus within the perennial Triticeae. As originally conceived by Dewey and Löve, Elymus contained species that were caespitose, small anthered, self-pollinating and contained the SH genomes. Chromosome pairing data in intergenomic hybrids has demonstrated that species in Elymus are heterogenomic with the SH, SY, SHY, and SYP genome combinations. The S, H, Y, and P genomes are distinct; however, low levels of homology apparently exist between the S and Y, and the S and P genomes. Under the genomic system of classification, each genome combination represents a new genus, thus splitting Elymus into four genera. Morphologically, the genomic groups SH, SY, and SHY are not distinct. Variation in leaf epidermal characters does not justify splitting of Elymus. Intergenomic hybrids between the three genomic groups are sterile; however, in nature natural hybridization between and within genomic groups occurs, creating character overlap which presents identification problems. Those species that are treated in Roegneria C. Koch section Paragropyrum, Elymus sections Hyalolepis and Goulardia, and Kengyilia gobicola comprise the S, Y, and P genomes and are morphologically similar to the crested wheatgrass complex (Agropyron Gaertn.) and may warrant generic rank

Cytogenetic and Molecular Characterization of Hybrids between 6x, 4x, and 2x Ploidy Levels in Crested Wheatgrass

The crested wheatgrass cultivar ‘Hycrest,’ which consists of germplasm from an induced tetraploid of Agropuron cristatum (2n = 4x = 28) (L.) Gaertn. and a natural tetraploid (2n = 4x = 28) of A. desertorum (Fisch. Ex Link) Schultes, was hybridized with a promising broadleaf hexaploid (6x‐BL; 2n = 6x = 42) accession of A. cristatum from the USSR. The goal was to combine the wide leaf characteristic and green color retention from the 6x‐BL parent into a common gene pool. The crossability between Hycrest (4x) and 6x‐BL (6x) was excellent; however, chromosome pairing was irregular and chromosome numbers ranged from 2n = 27 to 41. Leaf morphology in Hycrest/6x‐BL hybrids was intermediate to that of the parents. Selected F1 pentaploid progenies (2n = 5x = 35), with leaf widths approaching that of the 6x‐BL parent, were backcrossed to Hycrest (Hycrest*2/6x‐BL), and then crossed among themselves (Hycrest*2/6x‐BL//Hycrest*2/6x‐BL). In the backcross hybrid, chromosome numbers ranged from 2n = 28 to 39. Meiotically, 28 chromosome backcross hybrid plants were more stable than aneuploid backcross hybrids. The broadleaf character was readily detected in the backcross progeny. In Hycrest/6x‐BL//Hycrest/6x‐BL hybrids, chromosome numbers ranged from 2n = 33 to 45. Despite the hybrid origin, all aneuploid hybrids had an increased number of univalents and chromosome associations that involved more than four chromosomes. AFLP analysis reflected genetic introgression from the 6x‐BL parent beyond that observed in Hycrest. Results support earlier conclusions that the crested wheatgrass complex should be treated as a common gene pool.

Patterns and levels of genetic differentiation in North American populations of the Alaskan wheatgrass complex.

Levels and distribution of genetic variation were assessed using six allozymes in 27 populations of Alaskan wheatgrass (Elymus alaskanus) from different locations in Canada, USA, Greenland and Russia to obtain information on the genetic structure of these populations. The enzyme systems were ACO, DIA, GPI, MDH, PGM and SKD. Allozyme variation at the species level was high, with 64.3% (Ps) of the loci being polymorphic, an average number of alleles per locus of 1.9 (As), and an average genetic diversity of 0.17 (Hes). Differentiation was found in the populations studied, with the following findings: (1) statistically significant differences were found in allele frequencies among populations for every polymorphic locus (P < 0.001); (2) 63% of the total allozyme variation at polymorphic loci was partitioned among populations (GST = 0.63); (3) relatively low mean genetic distances between the populations were obtained (mean D = 0.029); (4) the genetic structure of Russian populations are clearly distinct from the other populations, the cluster and principal component analyses revealed the same genetic patterns of relationships among populations. This study also indicates that E. alaskanus contains different levels of allozyme variation in its populations. Furthermore, some banding patterns at the loci Aco-1, Aco-2, Gpi-2, Mdh-1, Skd-1, Skd-2 can be used as markers to identify individual populations.

A fertile amphiploid between durum wheat (Triticum turgidum) and the x Agroticum amphiploid (Agropyron cristatum x T. tauschii).

Agropyron (Gaertn) is a genus of Triticeae which includes the crested wheatgrass complex, i.e. A. cristatum (L.) as representative species containing the P genome. This species is an important source for increase the genetic variability of both durum and bread wheat. Among the possible interesting features to be introgressed into wheat are resistance to wheat streak mosaic virus, rust diseases, and tolerance to drought, cold and moderate salinity. By crossing tetraploid wheat (Triticum turgidum conv durum, 2n = 4x = 28; AABB) with a fertile allotetraploid (2n = 4x = 28; DDPP) between diploid wheat (T. tauschii) and crested wheatgrass (A. cristatum L.), amphiploid plants were obtained. Fluorescence in situ hybridization (FISH) using both genomic DNA from A. cristatum and the repetitive probe pAs1, proved that the plants were true amphiploids with a chromosome number 2n = 8x = 56 and genomic constitution AABBDDPP. Using total genomic in situ hybridization (GISH) to study meiotic metaphase I, data on allosyndetic and autosyndetic chromosome pairing were obtained. The amphiploids were perennial like the male parent but their morphology was close to that of the wheat parent. They were resistant to wheat leaf rust and powdery mildew under field conditions.

Genetic Relationships among Selected Crested Wheatgrass Cultivars and Species Determined on the Basis of AFLP Markers

The crested wheatgrass complex (Agropyron spp. Gaertn) consists of persistent, drought tolerant, tussock grasses, which originate from the steppes of central Asia and are of importance as range grasses on the Great Plains of North America. Amplified fragment length polymorphism (AFLP) markers were used to examine the interpopulation relationships and to compare variances within and among 12 populations from four Agropyron spp. [Agropyron cristatum (L.) Gaertn, Agropyron desertorum (Fisch ex Link) Schlut, Agropyron fragile (Roth) Candargy and Agropyron mongolicum Keng.] and two interspecific hybrid populations. Euclidean distances were calculated on the basis of marker polymorphism and a cluster analysis was performed on these populations. Fairway, Parkway, and S9240 grouped closely, and it is likely that these are the only true A. cristatum populations included in this study. Hycrest, CD-II, and Kirk grouped loosely between A. cristatum and A. desertorum. This confirms the hybrid nature of Hycrest and CD-II but may indicate that Kirk is incorrectly classified as A. cristatum, but is rather a hybrid. Agropyron desertorum cv. Nordan clustered loosely between A. cristatum and A. mongolicum, which is in agreement with the suggestion that A. desertorum is an alloploid of A. cristatum and A. mongolicum. The cultivars Vavilov, Douglas, and Ephraim clustered with A. desertorum. An analysis of molecular variance (AMOVA) was conducted on 15 individuals from six of the populations (Fairway, Parkway, S9240, Kirk, Hycrest, and Nordan). The majority (88%) of the AFLP variance was within populations, which was expected in these outcrossing populations; however, significant differences were still detected among all six populations. Relationships among the six genotypes were the same for the bulk and individual plant (AMOVA) analysis, suggesting that bulked samples can be used for phylogenic studies of different populations.

Cytogenetics of Eurasian Bluebunch Wheatgrass and Their Relationship to North American Bluebunch and Thickspike Wheatgrasses

Bluebunch wheatgrass, Pseudoroegneria spicata (Pursh.) A. Love, is one of the most important native dryland forage bunchgrasses of the intermountain West, which often produces depleted stands under moderate to heavy grazing pressure. In recent plant collecting trips to the Altai and Tien Shan Mountains of China and Russia, a grazing tolerant bluebunch wheatgrass complex was obtained. This study was conducted to describe the cytogenetic characteristics and potential for genetic exchange between the Eurasian bluebunch wheatgrass complex [P. strigosa (M. Bieb.) A. Love, P. geniculata (Trin.) A. Love, Roegneria elytrigioides Yen and Yang, and R. glaberrima Keng et S.L. Chen] and those bluebunch thickspike wheatgrasses found in North America. Meiotic behavior of the triploid hybrids between diploid and tetraploid R. glaberrima indicated that both ploidy levels share the same genome. Almost complete pairing in hybrids P. strigosa ssp. aegilopoides (Drob.) A. Love × P. spicata, and R. glaberrima × P. spicata, demonstrated that P. strigosa ssp. aegilopoides and R. glaberrima are comprised of the basic S genome. Triploid hybrids between P. geniculata, and R. elytrigioides with either P. spicata, P. stipifolia (Czern. ex Nevski) A. Love, or P. strigosa ssp. aegilopoides exhibited trivalent frequencies consistent with the hypothesis that tetraploid R. elytrigioides is an autotetraploid (SSSS) and that P. geniculata is either a segmental autotetraploid (S1S1S2S2) or an allotetraploid (SS??). Based on the high level of chromosome pairing in the interspecific hybrids between the Eurasian and North American bluebunch wbeatgrass complex, genetic exchange is possible. Due to the close genetic and morphological similarity among individuals of P. spicata, P. strigosa, P. geniculata, R. elytrigioides, and R. glaberrima we are likely dealing with a single, polymorphic, Eurasian‐North American species complex.

Production and identification of primary trisomics in diploid Agropyron cristatum (crested wheatgrass)

Six of the seven possible primary trisomics in Agropyron cristatum were produced. Based on morphology, arm length ratios, and C-banding patterns, they were identified as primary trisomics for chromosomes A, B, C, D, E, and G. Agropyron cristatum is one of several species constituting the crested wheatgrass complex. All species in this complex contain one basic genome (P). A study was conducted to produce and identify a primary trisomic series that will be used to map genes to individual chromosomes. A population of 157 plants were generated by crossing autotriploids (PPP) with diploid (PP) A. cristatum: 58 were diploid (2n = 14), 76 were primary trisomies (2n = 15), 17 were double trisomic (2n = 16), 4 were triple trisomics (2n = 14 + 3), 1 was telocentric trisomic (2n = 14 + 1 telo), and 1 was tetratrisomic (2n = 14 + 4). Karyotype analysis of acetoorcein-stained chromosomes was carried out using the CHROMPAC III computer program; for analysis of C-banded karyotypes, the computer imaging analysis program PCAS (Plant Chromosome Analysis System) was used to identify the primary trisomics. Of the 47 primary trisomics analyzed, 21 plants had one extra satellited chromosome E, 18 with the satellited D chromosome, 3 each for chromosomes B and G, and 1 each for chromosomes C and A. Chromosome pairing was studied in trisomies B, D, E, and G. Trisomics for chromosomes B and G were similar in their mieotic behavior. Each had a trivalent frequency of about 60% and pollen stainability of less than 40%. Trisomics for chromosomes D and E had a trivalent frequency of about 30% and pollen stainability of over 70%.

Genetic Progress through Hybridization of Induced and Natural Tetraploids in Crested Wheatgrass

Genetic Progress through Hybridization of Induced and Natural Tetraploids in Crested Wheatgrass

DROUGHT SURVIVAL OF SELECTED FORAGE GRASSES COMMONLY SEEDED IN THE NORTHERN GREAT PLAINS

Prolonged drought between 1979 and 1981 killed or severely reduced stands of a number of grass species presumably adapted and frequently recommended for seeding rangelands in the Northern Great Plains. The drought damage took place on recently planted as well as established 2 years or older seedings. Cultivars of the intermediate-pubescent wheatgrass complex were killed or most severely damaged. Damage was also severe on seeded stands of the native green needlegrass, western and thickspike wheatgrasses and big bluegrass. Crested wheatgrass was only moderately drought tolerant, but two cultivars of Russian wild ryegrass established well even with adverse moisture conditions in the seeding year. Altai wild ryegrass seedlings established well but did not survive the drought. An established stand of Vinall Russian wild ryegrass increased in basal area and produced leaf growth and seedstalks during the most severe drought periods. These periodic droughts are sporadic in occurrence but need to be considered in reference to species recommendations for range seedings in the Northern Great Plains.

Intermediate Wheatgrasses of Iran1

Geographic distribution, morphology, cytology, and fertility were studied in 247 collections of the intermediate wheatgrass complex (Agropyron intermedium (Host) Beauv., A. trichophorum (Link) Richt., and A. pulcherrimum Grossh.) collected in Iran and grown at Logan, Utah. This group of grasses is the most widespread Agropyron complex in Iran, occurring at altitudes of 500 to 2,700 m in the Alborz and Zagros mountain ranges and in semiarid plateau regions north of 30° N Lat. A 2,735‐plant population was extremely diverse in vegetative and spike characteristics. Plant breeders will find ample variation in these collections for significant improvement in forage and seed production. Of 234 plants, 93% had a chromosome number of 2n=42, and the remainder were 2n=41, 43, 45, and 52. Chromosome pairing at metaphase I averaged 0.60I, 20.19II, 0.05III, 0.20IV, 0.002V, and 0.008VI per cell in 1,926 cells. Pairing was in harmony with the hypothesis that intermediate wheat grasses are segmental autoallohexaploids. Open‐pollination fertility of 247 plants ranged from 0.0 to 72.8 seeds per spike and averaged 35.5. Self‐fertility of the same plants ranged from 0.0 to 44.4 seeds per spike and averaged 5.7. Occasional plants were highly self‐fertile, a condition previously unknown in these grasses. The spike characteristics that separate A. intermedium, A. trichophorum, and A. pulcherrimum taxonomically, i.e., pubescent vs. glabrous lemmas and awns vs. awnlessness, segregated in the population as if they were simply inherited traits. The three taxa cannot be separated on the basis of geographic distribution, ecological adaptation, cytological characteristics, or reproductive behavior. Consequently, all should be treated as a single species, A. intermedium.

Intermediate and Pubescent Wheatgrass Complex in Native Collections from Eastern Turkey1

Agropyron intermedium (Host) Beauv. and A. trichophorum (Link) Richt. have been distinguished on the basis of the first species having smooth glumes and lemmas, and the second being pubescent. This separation has broken down because both characters occurred within original introductions from Russia and are found even within selected varieties. This study was conducted on herbarium specimens and on progenies from plants open pollinated under natural conditions. Collections were made at 11 sites in Erzurum Valley in the vicinity of Ataturk University in Eastern Turkey to obtain information on the distribution of smooth and pubescent plants in naturally occurring colonies where the plants are native. Similar proportions of smooth and pubescent plants occurred irrespective of the location of the colonies, and segregation for pubescence occurred in families from both pubescent and smooth parents. It was concluded that the original introductions containing smooth and pubescent plants truly represented the native material and that the two taxa should be combined into a single species, A. intermedium (Host) Beauv.

Factors Influencing Water Absorption by Seeds of the Crested Wheatgrass Complex1

Seeds of crested wheatgrass Agropyron desertorum (Fisch. ex Link) Schult., Fairway wheatgrass A. cristatum (L.) Gaertn., and their hybrid were subjected to preplanting wetting treatments for various durations and rate of water absorption was determined. Within the temperature range 4.5 to 27.8 C absorption appeared directly proportional to temperature. Absorption was very rapid at the beginning, decreasing with time. In 12 hr seeds absorbed about half the total water absorbed in 90 hr. Percent increase in seed weight gave a linear relation with log of time. Rate of absorption differed significantly with different strains and seed lots. Breeder seed produced in different years on a single field of ‘Nordan’ crested wheatgrass yielded significantly different regressions, only partially explained by age, size of seed, or precipitation the year the seeds were produced. Variations in quality or quantity of water used or method of treatment did not yield consistent differences in rate of absorption.

Biosystematic Investigations in the Genus Agropyron Gaertn. III. Serological, Morphological, and Cytological Comparison of Species Within the Crested Wheatgrass Complex (Section Agropyron)1

Crop ScienceVolume 5, Issue 4 cropsci1965.0011183X000500040004x p. 316-320 Article Biosystematic Investigations in the Genus Agropyron Gaertn. III. Serological, Morphological, and Cytological Comparison of Species Within the Crested Wheatgrass Complex (Section Agropyron)1 Gordon C. Creel, Gordon C. CreelSearch for more papers by this authorJohn E. Ericson, John E. EricsonSearch for more papers by this authorJurgen Schulz-Schaeffer, Jurgen Schulz-Schaeffer Former Graduate Research Assistant and Graduate Research Assistant, Department of Plant and Soil Science, and Professor, Department of Plant and Soil Science and Department of Botany and Bacteriology, Montana State University, Bozeman. Contribution of the Montana Agricultural Experiment Station, Bozeman. Paper No. 662, Journal Series, Montana. Agricultural Experiment Station. Published with approval of director.Search for more papers by this author Gordon C. Creel, Gordon C. CreelSearch for more papers by this authorJohn E. Ericson, John E. EricsonSearch for more papers by this authorJurgen Schulz-Schaeffer, Jurgen Schulz-Schaeffer Former Graduate Research Assistant and Graduate Research Assistant, Department of Plant and Soil Science, and Professor, Department of Plant and Soil Science and Department of Botany and Bacteriology, Montana State University, Bozeman. Contribution of the Montana Agricultural Experiment Station, Bozeman. Paper No. 662, Journal Series, Montana. Agricultural Experiment Station. Published with approval of director.Search for more papers by this author First published: 01 July 1965 https://doi.org/10.2135/cropsci1965.0011183X000500040004x 1 These investigations were supported by the National Science Foundation, Grant NSF-G19363. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume5, Issue4July–August 1965Pages 316-320 RelatedInformation

Segmental Allopolyploidy in Tetraploid and Hexaploid Agropyron Species of the Crested Wheatgrass Complex (Section Agropyron)1

Segmental Allopolyploidy in Tetraploid and Hexaploid <i>Agropyron</i> Species of the Crested Wheatgrass Complex (Section Agropyron)¹

Comments on "the Nomenclature of the Crested Wheatgrass Complex by A. A. Beetle"

Comments on "the Nomenclature of the Crested Wheatgrass Complex by A. A. Beetle"

Wheatgrass Variety Performance on Summer Rangeland in Northeastern California

SynopsisAgropyron tricophorum, A. intermedium, and A. elongatum appeared better adapted to the area than species in the crested wheatgrass complex.

The Nomenclature of the Crested Wheatgrass Complex

The recent appearance of the name Agropyron desertorum (Fisch.) Schult. in range management literature, the continued use of A. cristatum (L.) Gaertn., and the employment of the common name “crested wheatgrass” for both has led to a confusion in the literature which needs clarification. Additionally, the closely related species of the A. michnoi Roshev. complex as well as A. sibiricum (Willd.) Beauv., A. pachyrrhizum Camus, A. mongolicum Keng, A. pectiniforme, R. and S., A. fragile (Roth) Nevski, A. imbricatus R. and S., and others are poorly defined.’ The true answers to such nomenclatorial puzzles usually lie in the homeland of the species involved, in this case largely behind the “iron curtain.” Pending more detailed field studies in regions where these species are native, Americans would seem well advised to accept the consensus of the best Old World analyses available. There seems to be general agreement that this group was first introduced and propagated as a mixed germplasm involving both A. desertorum and A. cristaturn. Until the publication of. the second edition of Hitchcock’s Manual (1952)) all of this material was referred to as Agropyron cristutum. However, when Swallen revised the Hordeae for the second edition he recognized three species: (1) A. cristutum (crested wheatgrass), (2) A. desertorum (no common name), (3) A. sibiricum (no common name). In 1953 Weintraub recognized not only these three but additionally A. michnoi and recommended common names as follows: TECHNICAL NOTES