Russian Wildrye Research Articles

Allozyme diversity of Russian wildrye accessions

AbstractAnalysis of genetic diversity among plant accessions plays an important role in developing strategies for plant breeding and the conservation of genetic resources. Therefore, we sought to estimate the extent of genetic diversity present among and within 29 Russian wildrye accessions, which were collected from widespread geographic sites. We assessed the genetic diversity of eight enzymes found in 29 Russian wildrye accessions using vertical polyacrylamide gel electrophoresis. The genetic diversity of each accession was estimated from standard genetic parameters that included (1) the number of polymorphic loci; (2) the average number of alleles per locus; (3) the observed and expected heterozygosity. The eight enzymes were encoded by 13 putative loci and 46 alleles. Allozyme analyses revealed a large number of polymorphic loci among the 29 accessions and some of the accessions carry rare alleles and trace their origin to sites in Xinjiang, China, where Russian wildrye is indigenous. The accessions with rare alleles require additional evaluation to determine whether they possess unique phenotypic traits which would be useful in applied plant breeding.

Early seedling growth and forage production of diploid and tetraploid crested wheatgrass and Russian wildrye cultivars

Cultivars selected for improved seedling vigour may also differ in seedling growth and subsequent forage production. The objective of this project was to compare three cultivars of crested wheatgrass (CWG) and four cultivars of Russian wildrye (RWR) for seedling growth in a greenhouse (GH) trial and two field trials when seeded at 15, 30 and 45 mm depths. Cultivars were Goliath, Kirk and Parkway CWG and SCR39903, Swift, Tetracan, and Tom RWR. Seedling emergence, tiller number, and seedling biomass were determined at 28 d after seeding (DAS) in all three trials. In addition, forage dry matter (DM) yield was determined for 2 yr in the field trials. Small-seeded diploid Parkway crested wheatgrass had reduced emergence at 45 mm seeding depth compared with larger-seeded tetraploid Kirk and Goliath. Goliath had reduced tillering compared with the other two CWG cultivars. The emergence of Tetracan tetraploid RWR was greater at deeper seeding depth than diploid cultivars, SCR39902, Swift and Tom in Field Trial 2, but not in Field Trial 1 and the GH trial. Seedling tiller number of Tetracan RWR was less than that of the other three cultivars. Two-year total CWG forage DM yield in the field was best correlated to emergence. In contrast, 2-yr total RWR forage DM was best correlated to seedling tiller number in GH and Field Trial 2 despite the low tiller numbers at 28 d after seeding. Field emergence of Russian wildrye did not appear to be limiting to seedling establishment in contrast to previous reports. Selection in RWR should include seedling tiller number in combination with seedling emergence in order to improve both seedling vigour and forage productivity. Key words: Establishment, tiller, emergence, forage yields, seedling depth

Surface runoff response of native and introduced grasses under simulated rainfall in southern Alberta

Introduced perennial grass-based pastures (e.g., crested wheatgrass, Agropyron cristatum, and Russian wildrye, Elymus junceus) are promoted as desirable alternatives to natural grasslands (Stipa-Bouteloua-Agropyron spp.) for livestock production systems on the mixed-grass prairie of Alberta. A study was conducted on plots established in 1993 to examine the surface runoff response from natural grasslands, introduced grasses and spring wheat (Triticum aestivum L.) under simulated rainfall in response to pasture and soil characteristics. The grass plots were never grazed, but herbage growth was harvested on an annual basis, while wheat was seeded each year following tillage. Both wheat and crested wheatgrass were less able to retain applied water; with low initial abstraction (5.1–5.7mm), runoff peaked earlier (14–26 min) and with higher intensity (65.1–68.8mm h-1) giving larger values of the rising limb factor (0.61–1.10). Two grasslands dominated by native species showed more desirable runoff characteristics; with high initial abstraction (9.6–13.3mm), runoff peaked later (32–54 min) and with lower intensity (32.7–45.8mm h-1) giving smaller values of the rising limb factor (0.13–0.35). Russian wildrye had an intermediary response. A linear model identified that to reduce the rising limb factor and amount of runoff generated after 30 min, the antecedent conditions of ground cover (%), litter dry matter (DM) and dead herbage DM were singularly important variables and the native grasslands had significantly higher levels of these. Importantly, fine and medium litter fragments of natural grasslands had higher water-holding capacity (>3.0 g g-1) compared with litter of the introduced species (~2.5 g g-1). However, when variables were considered in combination runoff decreased with higher ground cover and increased with higher soil water content. Levels of total N and total P in surface runoff were generally low (< 2 mg N L-1, < 1 mg P L-1), but ammonium and reactive P export from the native species was greater than for the introduced species. Suspended sediment yield did not differ among the grassland treatments, but was significantly higher for wheat. Less runoff was generated on grasslands that had high amounts of litter, dead standing herbage and ground cover. Increasing the amount of litter in pastures by using grazing management may decrease the runoff response and so avoid loss of surface water and soil nutrients. Key words: Ground cover, litter, water quality, native grasses, nutrients

Arbuscular mycorrhizal fungi and nematodes are involved in negative feedback on a dual culture of alfalfa and Russian wildrye

The complex biological interactions taking place in soil–plant systems may sometimes alter the functioning of an ecosystem. We examined the relationship between arbuscular mycorrhizal (AM) root colonization, nematode populations, and plant competition in an 8-year-old field experiment comparing alfalfa monoculture to dual culture of alfalfa ( Medicago sativa L.) and Russian wildrye ( Psathyostachys juncea Fisch. Nevski) (RWR) grown under different soil P fertility levels, in a Brown Chernozemic soil in Saskatchewan. The experiment included three P rates: 0, 20 and 40 kg P 2O 5 ha −1 (0P, 20P and 40P) applied annually and was sampled three times during the cropping season: 30 June, 1 September and 30 September. Higher AM symbiotic development compensated for reduced soil P fertility in alfalfa stands without RWR and forage dry matter yield was not affected by P rates. But in the presence of RWR, reduced soil P fertility at 0P and 20P led to forage yield reduction. Fertilization treatments modified the soil microbial community structure only in the presence of RWR, as revealed by discriminant analysis of the profiles of microbial phospholipids fatty acid in soil lipid extracts and functional nematode groups. Arbuscular mycorrhizal root colonization level was reduced with P fertilizer both in the presence and absence of RWR. In the presence of RWR, lower plant AM root colonization was concurrent with higher abundance of total, fungivorous and omnivorous nematodes. Our results are consistent with a model of negative feedback from the plant-associated soil microflora where the presence of RWR increased the population of fungivorous nematodes and grazing of AM hyphae. Negative impacts were larger in low P fertility soils promoting AM symbiotic development. The unexpected decrease in alfalfa–RWR dual culture yield under 0P and 20P fertilization levels was attributed to a carbon drain created by enhanced nematode feeding on AM fungi in the presence of RWR.

Breeding potentials in perennial Triticeae grasses

Perennial Triticeae species comprise some of the most valuable grasses in the temperate regions of the world, in addition, they have been a source of genes for pest resistance and other traits in wide hybridization programs to improve cultivated cereal crops. Intense breeding efforts have been restricted primarily to species of Agropyron (Gaertn.), Psathyrostachys Nevski, Thinopyrum Love, Leymus Hochst., Elymus L., and Pseudoroegneria (Nevski) Love. Crested wheatgrass (Agropyron ssp.) has received the most attention in breeding programs as evidenced by the release of several improved cultivars. Stand establishment vigor of Russian wildrye, Psathyrostachys juncea (Fisch.) Nevski, has been substantially increased through breeding, and selection for improved forage quality and disease resistance has been effective in intermediate wheatgrass, Thinopyrum intermedium (Host) Barkw. & Dewey. Interspecific hybridization is a promising breeding procedure in the perennial Triticeae. The recently released cultivars ‘Hycrest’ and ‘NewHy’ are notable examples of progress through interspecific hybridization. ‘Hycrest’ was derived from hybrids between induced tetraploid Agropyron cristatum (L.) Gaertn. and natural tetraploid Agropyron desertorum (Fisch. ex Link) Schultes. The parentage of ‘NewHy’ traces to hybrids between quackgrass, Elytrigia repens (L.) Nevski, and bluebunch wheatgrass, Pseudoroegneria spicata (Pursh) Love. Genetic progress through induced amphiploidy has also been reported. Continued success in breeding programs will be accelerated by expanded plant exploration efforts along with improved technology and breeding methods.

Breeding potentials in perennial Triticeae grasses

Perennial Triticeae species comprise some of the most valuable grasses in the temperate regions of the world, in addition, they have been a source of genes for pest resistance and other traits in wide hybridization programs to improve cultivated cereal crops. Intense breeding efforts have been restricted primarily to species of Agropyron (Gaertn.), Psathyrostachys Nevski, Thinopyrum Löve, Leymus Hochst., Elymus L., and Pseudoroegneria (Nevski) Löve. Crested wheatgrass (Agropyron ssp.) has received the most attention in breeding programs as evidenced by the release of several improved cultivars. Stand establishment vigor of Russian wildrye, Psathyrostachys juncea (Fisch.) Nevski, has been substantially increased through breeding, and selection for improved forage quality and disease resistance has been effective in intermediate wheatgrass, Thinopyrum intermedium (Host) Barkw. & Dewey. Interspecific hybridization is a promising breeding procedure in the perennial Triticeae. The recently released cultivars ‘Hycrest’ and ‘NewHy’ are notable examples of progress through interspecific hybridization. ‘Hycrest’ was derived from hybrids between induced tetraploid Agropyron cristatum (L.) Gaertn. and natural tetraploid Agropyron desertorum (Fisch. ex Link) Schultes. The parentage of ‘NewHy’ traces to hybrids between quackgrass, Elytrigia repens (L.) Nevski, and bluebunch wheatgrass, Pseudoroegneria spicata (Pursh) Löve. Genetic progress through induced amphiploidy has also been reported. Continued success in breeding programs will be accelerated by expanded plant exploration efforts along with improved technology and breeding methods.

Seventy Years of Pasture Rejuvenation Research

pasture, 48 km north of the city of Swift Current, Saskatchewan. Later in the 1960s and 1970s, an international research center was established at the Matador pasture as part of a world-wide attempt to collect data on representative ecosystems and to develop computer models of them. Many of the world's present-day ecologists worked in the program as student help during data collection and analysis. The results were published in approximately 25 volumes, each the size of a big city phone book. A summary of the overall results can be found on www.foragebeef.ca. During the Dirty Thirties researchers at Agriculture and Agri-Food Canada at Swift Current and Prairie Farm Rehabilitation Administration (PFRA) began to reestablish drought-stricken pastures in the southern prairies with new varieties of Russian wild rye and crested wheat grass. The involvement of PFRA in pasture and range development started in 1935 along with soil reclamation, tree planting, and water development projects. By the end of 1937, 16 provincial community pastures involving 175,900 acres had been established in Saskatchewan. In addition, thirty more potential pasture areas had been surveyed for development encompassing about 400,000 acres, and 5 reserve areas were proposed to be taken out of annual cropping, reseeded to grass, and used for supplemental forage for wintering livestock. Eight pastures totaling 595,840 acres were established by the Alberta government during this time. Many additional community pastures were developed in Saskatchewan in the 1950s and 1960s. The land came from

Seeding Cool-season Grasses to Suppress White Locoweed (Oxytropis Sericea) Reestablishment and Increase Forage Production

Livestock poisoning can occur on short-grass prairies when locoweeds are actively growing in spring before warm-season grasses begin growth. White locoweed grows in early spring, completes flowering and seed production by early summer, and goes dormant. Perennial cool-season grasses may provide competition to suppress locoweed or reduce its reestablishment following control. Furthermore, these grasses may provide alternative palatable forage to livestock early in the spring. The objective of this study was to suppress white locoweed reinvasion by seeding cool-season grasses at two mixed-grass and two short-grass prairie sites. White locoweed and associated species were controlled with glyphosate (1.1 kg ai/ha) and picloram (0.38 kg ae/ha) in 3 by 15 m plots. The plots were seeded to ‘CDII’ crested wheatgrass, ‘Vavilov’ Siberian wheatgrass, ‘Luna’ pubescent wheatgrass, ‘Bozoisky’ Russian wildrye, smooth brome, ‘NewHy’ wheatgrass, sideoats grama, and ‘Immigrant’ forage kochia. In addition, a native grass pl...

Evaluation of the “bait-lamina test” to assess soil microfauna feeding activity in mixed grassland

The soil fauna plays an important role in regulating nutrient cycling through predation and comminution of organic residues. The bait-lamina test was proposed as a practical mean to assess soil faunal feeding activity. The test consists of vertically inserting 16-hole-bearing plastic strips filled with a plant material preparation into the soil. We assessed the value of the bait-lamina test in the mixed grassland ecoregion of Canada, using 5-year-old seeded grass field plots. There were five treatments of grass communities, i.e. monocultures of (1) Russian wild rye, (2) switchgrass, (3) green needlegrass, or (4) western wheatgrass, and (5) a grass mixture of western wheatgrass + green needlegrass + switchgrass + little blue stem, which were distributed in four complete blocks, and six bait mix treatments, i.e. bait made with ground tissue of (1) Russian wild rye, (2) switchgrass, (3) green needlegrass, (4) western wheatgrass, (5) alfalfa, or with (6) wheat bran, which were randomized in each plot. Bait-lamina strips were used in groups of five strips inserted in the soil; they were equally spaced across the inter-row. The analysis revealed a marginally significant effect ( P = 0.065) of plant community on soil faunal feeding activity with more activity in mixed grass species compared to green needlegrass plots. Bait flavour had no significant effect ( P = 0.22) on feeding. More ( P < 0.0005) feeding activity was detected close to the soil surface (0–5 mm deep) than at 20 mm below the surface and at deeper depths. Feeding activity was relatively low over the 65-day period of the test (13 June to 17 August 2005), with 8.3% and 2.0% of the lamina (holes filled) showing signs of feeding in the 0–5 and 5–15 mm soil layer. We conclude that the bait-lamina test is appropriate to assess the activity of surface litter processing fauna in mixed grassland, but it is not a good indicator of the decomposition occurring in the soil matrix, where most litter is produced. We recommend the use of a large number of replicated bait-lamina strips and a whole growing season incubation period in soils of the semiarid prairie ecoregion where the surface litter layer is thin and faunal saprobes are relatively scarce.

Competition, light quality and seedling growth of Russian wildrye grass (Psathyrostachys juncea)

The low seedling vigour of Russian wildrye grass ( Psathyrostachys juncea ) (RWR) limits its use. Shading from durum wheat ( Triticum turgidum ) reduced RWR leaf number, tiller number, leaf area and seedling dry weight in a growth room experiment. Treatments with similar shading differed in tiller number and dry weight, which suggested that light quality may have also contributed to these responses. In a second growth room experiment, light intensity (PAR) and red:far-red light ratio (670:730 nm) were altered by coloured plastic filters suspended above seedlings of Russian wildrye, crested wheatgrass ( Agropyron desertorum ) (CWG) and Dahurian wildrye grass ( Elymus dahuricus ) (DWR). Leaf area, tiller number and dry weight of RWR seedlings were reduced by declining red:far-red light ratio while light intensity differences at similar red:far-red ratio did not affect these variables. CWG exhibited similar responses to declining red:far-red light ratio as RWR, except that it exhibited a seedling weight response to light intensity. DWR tiller number was not responsive to low red:far-red light ratio but rather to low light intensity. However, DWR seedling weight, tiller weight and leaf area were responsive to declining red:far-red light ratio. These results indicate that RWR seedlings are sensitive to light quality changes caused by neighbouring plants.

Evaluation of elemental allelopathy in Acroptilon repens (L.) DC. (Russian Knapweed)

Although Acroptilon repens (L.) DC. (Russian knapweed) is known to concentrate zinc (Zn) in upper soil layers, the question of whether the elevated Zn has an allelopathic effect on restoration species has not been addressed. Experiments were conducted to investigate whether soils collected from within infestations of A. repens (high-Zn) inhibit the germination or growth and development of desirable restoration species, compared to soils collected adjacent to an A. repens infestation (low-Zn). Four bioassay species [Sporobolus airoides (Torrey) Torrey (alkali sacaton), Pseudoroegneria spicata (Pursh) A. Love (bluebunch wheatgrass), Psathyrostachys juncea (Fischer) Nevski (Russian wildrye) and A. repens] were germinated in a growth chamber and grown in a greenhouse in both soils and received treatments for the alleviation of Zn toxicity (P, Fe, Fe-oxide, and soil mixing) to isolate the effects of elevated soil Zn on plant performance. Percent germination, total plant biomass, tiller and stem number, inflorescence number, and tissue metal levels were compared among soil types and treatments for each species. There was no evidence from any of the indicators measured that high-Zn soils reduced plant performance, compared to low-Zn soils. Tissue Zn levels barely approached the lower range of phytotoxic levels established for native grasses. Older plants with longer exposure times may accumulate higher Zn concentrations. S. airoides and A. repens both had higher biomass in the high-Zn soil, most likely due to increased macronutrient (N and P) availability. As the Zn levels in the soils used in this study were much higher than any levels previously reported in soils associated with A. repens, it is unlikely that the elevation of soil Zn by A. repens will hinder germination or growth and development of desirable grasses during establishment.

English

Relationships between electrical conductivity (EC) and sodium adsorption ratio (SAR) changes over time in reconstructed soils at surface coal mining operations are insufficiently documented in the literature. Some minesoils (i.e., rootzone material) are classified as saline, sodic, or saline-sodic and have been considered unsuitable rooting media for establishment of native vegetation. Weatherable minerals (e.g., pyrite, calcite, gypsum, and other geologic substrates) commonly present in minesoils can mitigate the effects of elevated SAR levels by maintaining or increasing electrolytes in the soil and provide sources of exchangeable calcium and magnesium. Coversoil (i.e., topsoil) enhances this mitigation through physical and chemical buffering of minesoils. Weathering characteristics of minesoils and rooting patterns of key reclamation species were evaluated at sites from three surface coal mines in northwestern New Mexico and northeastern Arizona. Unweathered minesoils were grouped into 11 classifications based on EC and SAR. Comparison of saturated paste extracts from unweathered and weathered (6 to 14 years after reclamation) minesoils show significant (p < 0.05) reductions in SAR levels and increased EC. Weathering increased the apparent stability of saline and sodic minesoils thereby reducing risks of aggregate slaking and clay particle dispersion. Root density of fourwing saltbush (Atriplex canescens), alkali sacaton (Sporobolus airoides), and Russian wildrye (Psathyrostachys junceus) were generally unaffected by increasing minesoil EC and SAR levels. Saline and sodic minesoils can be successfully reclaimed when covered with topsoil and seeded with salt tolerant plant species.

Registration of ‘Bozoisky‐II’ Russian Wildrye

Crop ScienceVolume 46, Issue 2 p. 986-987 Registrations of Cultivar Registration of ‘Bozoisky-II’ Russian Wildrye K.B. Jensen, Corresponding Author K.B. Jensen kevin@cc.usu.edu USDA-ARS, Forage and Range Res. Lab., Utah State Univ., Utah State, UT, 84322-6300Corresponding author (kevin@cc.usu.edu)Search for more papers by this authorK.H. Asay, K.H. Asay USDA-ARS, Forage and Range Res. Lab., Utah State Univ., Utah State, UT, 84322-6300Search for more papers by this authorD.A. Johnson, D.A. Johnson USDA-ARS, Forage and Range Res. Lab., Utah State Univ., Utah State, UT, 84322-6300Search for more papers by this authorS.R. Larson, S.R. Larson USDA-ARS, Forage and Range Res. Lab., Utah State Univ., Utah State, UT, 84322-6300Search for more papers by this authorB.L. Waldron, B.L. Waldron USDA-ARS, Forage and Range Res. Lab., Utah State Univ., Utah State, UT, 84322-6300Search for more papers by this authorA.J. Palazzo, A.J. Palazzo US Army Corps of Engineers, Engineering Research and Development Center, Cold Regions Research and Engineering Laboratory (ERDC-CRREL), Hanover, NHSearch for more papers by this author K.B. Jensen, Corresponding Author K.B. Jensen kevin@cc.usu.edu USDA-ARS, Forage and Range Res. Lab., Utah State Univ., Utah State, UT, 84322-6300Corresponding author (kevin@cc.usu.edu)Search for more papers by this authorK.H. Asay, K.H. Asay USDA-ARS, Forage and Range Res. Lab., Utah State Univ., Utah State, UT, 84322-6300Search for more papers by this authorD.A. Johnson, D.A. Johnson USDA-ARS, Forage and Range Res. Lab., Utah State Univ., Utah State, UT, 84322-6300Search for more papers by this authorS.R. Larson, S.R. Larson USDA-ARS, Forage and Range Res. Lab., Utah State Univ., Utah State, UT, 84322-6300Search for more papers by this authorB.L. Waldron, B.L. Waldron USDA-ARS, Forage and Range Res. Lab., Utah State Univ., Utah State, UT, 84322-6300Search for more papers by this authorA.J. Palazzo, A.J. Palazzo US Army Corps of Engineers, Engineering Research and Development Center, Cold Regions Research and Engineering Laboratory (ERDC-CRREL), Hanover, NHSearch for more papers by this author First published: 01 March 2006 https://doi.org/10.2135/cropsci2005.06-0163Citations: 5 Utah Agic. Exp. Stn. Journal Article No. 7703. Registration by CSSA. Read the full textAboutPDF 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 No abstract is available for this article.Citing Literature Volume46, Issue2March–April 2006Pages 986-987 RelatedInformation

Heifer Production on Rangeland and Seeded Forages in the Northern Great Plains

Integrating use of seeded perennial cool-season grass pastures with native rangeland can increase available forage and provide a high plane of nutrition for grazing livestock. Our objective was to compare performance of yearling beef heifers grazing native rangeland with those grazing an integrated system that included seeded forages. Twice-replicated, 3-ha pastures seeded to either ‘Rosana’ western wheatgrass ( Pascopyron smithii [Rydb.] A. Love), ‘Luna’ pubescent wheatgrass ( Elytrigia intermedia [Host] Nevski), or ‘Hycrest’ crested wheatgrass ( Agropyron cristatum [L.] Gaertn. ssp. desertorum [Fisch. ex Link] A. Love) were grazed in spring, whereas twice-replicated, 3.24-ha pastures seeded to either ‘Alkar’ tall wheatgrass ( Thinopyrum ponticum [Podp.] ZW Liu & RC Wang), ‘NewHy’ hybrid wheatgrass ( Elymus hoffmannii KB Jensen & KH Asay), ‘Bozoisky’ Russian wildrye ( Psathyrostachys juncea [Fisch.] Nevski.), or ‘Prairieland’ Altai wildrye ( Leymus angustus [Trin.] Pilger) were grazed in autumn. Native rangeland was grazed during summer in the integrated system and spring, summer, and autumn in the rangeland treatment. Heifers exhibited greater weight gains on seeded pastures than on native rangeland in spring and autumn of most years. In 2 out of 3 years, heifers that grazed native rangeland during spring gained more ( P = 0.012 for gain head −1 and P = 0.021 for gain head −1 day −1 ) while grazing native rangeland during summer than heifers that grazed seeded pastures in spring. Spring + summer gains averaged (mean ± SE) 0.56 ± kg·head −1 ·d −1 and 73.1 ± kg·head −1 . Livestock managers need to consider their livestock marketing and management strategies when using seeded pastures for seasonal grazing. La integración del uso de praderas sembradas de zacates perennes de estación fría con pastizal nativo puede incrementar el forraje disponible y proveer un buen plano nutricional para el ganado en apacentamiento. Nuestro objetivo fue comparar el comportamiento productivo de vaquillas de ganado de carne de año apacentando un pastizal nativo con vaquillas apacentando un sistema integrado que incluía forrajes sembrados. Praderas de 3 ha, repetidas dos veces, sembradas con “Western wheatgrass” ( Pascopyron smithii [Rydb.] A. Love) variedad ‘Rosana’ y “Pubescent wheatgrass” ( Elytrigia intermedia [Host] Nevski) variedad ‘Luna’ o con “Crested wheatgrass” ( Agropyron cristatum [L.] Gaertn. ssp. desertorum [Fisch. ex Link] A. Love) variedad ‘Hycrest’ fueron apacentadas en primavera, mientras que praderas de 3.24 ha, repetidas dos veces, sembradas con “Tall wheatgrass” ( Thinopyrum ponticum [Podp.] ZW Liu & RC Wang) variedad ‘Alkar’, “Hybrid wheatgrass” ( Elymus hoffmannii KB Jensen & KH Asay) variedad ‘NewHy’, “Russian wildrye” ( Psathyrostachys juncea [Fisch.] Nevski.) variedad ‘Bozoisky’ o con “Altai wildrye” ( Leymus angustus [Trin.] Pilger) variedad ‘Prairieland’ fueron apacentadas en otoño; en el sistema integrado, el pastizal nativo fue apacentado en verano y en el tratamiento de solo pastizal se apacentó en primavera, verano y otoño. En la mayoría de los años, las vaquillas mostraron mayores ganancias de peso en las praderas sembradas que los obtenidos en el pastizal nativo en primavera y otoño. En 2 de 3 años, la vaquillas que apacentaron el pastizal nativo durante la primavera, ganaron más peso ( P = 0.012 para ganancia cabeza −1 y P = 0.021 para la ganancia cabeza −1 dia −1 ) cuando apacentaban el pastizal en verano que las vaquillas que apacentaron en primavera las praderas sembradas. Las ganancias de primavera + verano promediaron 0.56 ± kg·cabeza −1 ·d −1 y 73.1 ± kg·cabeza −1 . Cuando utilicen praderas sembradas para el apacentamiento estacional, los manejadores de ganado necesitan considerar su mercadeo del ganado y estrategias de manejo.

Characterization of Hybrids from Induced × Natural Tetraploids of Russian Wildrye

Because of restrictions imposed by hybridization barriers, Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski] breeders have usually limited themselves to selection and hybridization within ploidy levels. Plants of diploid (2n = 2x = 14) Russian wildrye tend to be shorter, finer stemmed, leafier, and generally higher in forage production than tetraploids (2n = 4x = 28), which have larger seeds and superior seedling vigor. The principle objectives of the present study were to combine the genes from diploid and tetraploid Russian wildrye into a stable population, and evaluate variability in chromosome behavior, molecular genetic diversity, forage production, seed characteristics, and seedling vigor of the hybrids. Cytologically, the hybrid population behaved as an autotetraploid averaging 0.50 univalents + 9.37 bivalents + 0.24 trivalents + 1.98 quadrivalents per cell. Narrow‐sense heritabilities were 31, 63, 17, and 23% for dry matter yield (DMY), total seed yield, 100‐seed weight, and rate of seedling emergence, respectively. Coefficients of determination (r2) among parent and half‐sib family means were 0.12, 0.29, 0.09, and 0.72 for the above traits, respectively. Essentially all variation among half‐sib families for rate of seedling emergence was associated with environmental effects. Positive responses to selection pressure for improved seed yield, rate of seedling emergence, and dry matter production were achieved and additional gains are expected. Any major improvement in seed mass would be limited without broadening the genetic base of the hybrid.

Coexistence of Native and Introduced Perennial Grasses following Simultaneous Seeding

Revegetation of disturbed semiarid lands requires rapid stabilization of ecological process and soil resources. Introduced species have been widely adopted because the slow establishment of native species frequently results in poor ecosystem recovery and further site degradation. Little research has documented the managerial possibilities and species interactions associated with simultaneously establishing native and introduced grasses on semiarid lands. We conducted a 3‐yr experiment at Fort Carson, CO, to evaluate if seven native perennial grasses would coexist with either Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski], crested wheatgrass (Agropyron sp.), or Siberian wheatgrass [A. fragile (Roth) Candargy] after simultaneous seeding. Five grass mixes, each comprised of the seven natives and one introduced grass, and a standard military seed mix (mostly native grasses with a small introduced species component) were evaluated by comparing percentage ground cover of individual species. Predominance of crested and Siberian wheatgrass cover resulted in significantly lower native grass and weed abundance. In contrast, Russian wildrye and military treatments had lower introduced grass cover and high weed abundance, but much higher native grass cover. However, weed cover decreased to &lt;5% in all treatments during the experiment. Western wheatgrass [Pascopyrum smithii (Rydb.) A. Löve] was responsible for &gt;80% of the native species cover in the military treatment for all 3 yr, whereas the Russian wildrye treatments had a more balanced mix of several native species. These results provide insights into managerial considerations for revegetation and weed control for frequently disturbed rangelands and suggest that some introduced grasses may coexist with native grasses.

Performance of Perennial Cool‐Season Forage Grasses in Diverse Soil Moisture Environments, Southern High Plains, USA

A continuing need exists to evaluate grasses for irrigated pastures in new and marginal environments. Persistence and yield of Altai wildrye, Leymus angustus (Trin.) Pilg.; beardless wildrye, L. triticoides (Buckley) Pilg.; creeping foxtail, Alopecurus arundinaceus Poir.; grazing bromegrass, Bromus stamineus E. Desv.; intermediate‐pubescent wheatgrass, Elytrigia intermedia (Host) Nevski; meadow bromegrass, B. riparius (Rehmann); meadow fescue, Festuca pratensis (Huds.); orchardgrass, Dactylis glomerata (L.); prairie bromegrass, B. willdenowii (Kunth), syn. B catharticus Vahl var. catharticus; reed canarygrass, Phalaris arundinacea L.; RS wheatgrass, E. repens var. repens L. Desv. ex B.D. Jackson × Pseudoroegneria spicata (Pursh) A. Love; Russian wildrye, Psathyrostachys juncea (Fisch.) Nevski; smooth bromegrass, B. inermis Leyss.; tall fescue, F. arundinacea Schreb.; tall wheatgrass, E. elongata (Host) Nevski; and western wheatgrass, Pascopyrum smithii (Rybd.) A. Love, sown in late summer 1997, were measured from 1999 to 2001 at Tucumcari, NM. Soil moisture treatments were (i) furrow irrigated once before each harvest, which is typical management; (ii) typical irrigation plus irrigated monthly during winter; and (iii) poorly drained, saline/sodic soil, irrigated less than once per cutting. Russian wildrye, RS wheatgrass, tall fescue, tall wheatgrass, and western wheatgrass maintained ground cover across soil moisture treatments. Stand development by Altai wildrye and smooth bromegrass was inconsistent across soil moisture treatments, but eventually complete. Beardless wildrye established stands only in poorly drained soil, while intermediate‐pubescent wheatgrass and meadow bromegrass did not establish well in that soil. No other species established or maintained satisfactory stands after 3 yr in any soil moisture treatment. Winter irrigation increased early‐season yield of intermediate‐pubescent wheatgrass, but decreased late‐season yields of several species, especially Altai wildrye. Distribution of tall wheatgrass and Altai wildrye yield appear complementary, and a binary mixture might provide uniform season‐long yields in this region.

Evaluation of Native and Introduced Grasses for Reclamation and Production

Crested wheatgrass (Agropyron cristatum [L.] Gaertn.) and Russian wildrye (Elymus junceus Fisch.) are commonly used for reseeding in the more xeric Mixed Prairie of the Canadian prairies because they are perceived to be more productive than native species. However, they have been implicated in soil deterioration. The objectives of our study were to compare the aboveground net primary production and soil organic carbon (C) among monoculture communities of selected native grass species, crested wheatgrass, and Russian wildrye and to compare the native grass monocultures with their mixtures. In 1995, a 5-year study was initiated on Dark Brown Chernozemic (Typic Haploboroll) soil near Lethbridge, Alberta. Ten treatments consisting of monocultures of introduced and selected native species and mixtures of native species were established in a randomized complete block design with 4 replications. Aboveground net primary production and soil organic C were measured. Monocultures of 2 native species, green needlegrass (Stipa viridula Trin.) and blue grama (Bouteloua gracilis [H.B.K.] Lag. ex Steud.), were more productive than crested wheatgrass or Russian wildrye under both normal moisture and drought conditions. Monocultures of these native species also tended to be more productive than their mixtures. The western wheatgrass (A. smithii Rydb.) monoculture and the western wheatgrass–blue grama mixture experienced the greatest yield reduction as a result of drought. Treatment effects on soil organic C were not detected (P > 0.05) 5 years after seeding. Soils of the June grass (Koeleria macrantha [Ledeb.] J.A. Schultes f.) community had less (P < 0.05) macro-organic C than most other treatments.

Response of Perennial Cool‐Season Grasses to Clipping in the Southern Plains

Many forage‐livestock systems in the Southern Plains depend on the use of winter wheat (Triticum aestivum L.) and rye (Secale cereale L.) to support rapid gains of growing beef cattle (Bos taurus L.) from November through May. Complementing these annuals with cool‐season perennial grasses could reduce inputs and soil erosion, but these perennial grasses have not been extensively tested under dryland conditions in this region. We determined the production potential and response to clipping of four Triticeae grasses under dryland conditions on a Grandfield fine sandy loam (fine‐loamy, mixed, superactive, thermic Typic Haplustalf). ‘Barton’ western wheatgrass [Pascopyrum smithii (Rydb.) A. Löve], ‘Luna’ intermediate wheatgrass [Elytrigia intermedia (Host) Nevski subsp. intermedia ], ‘Jose’ tall wheatgrass [Elytrigia elongata (Host) Nevski], and ‘Bozoisky‐Select’ Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski] were harvested at either 10 or 15 cm at 30‐, 45‐, or 60‐d intervals. Forage production was different among species in only 1 of 3 yr. Despite above‐average winter and spring precipitation, production declined for all grasses over years, averaging 2270, 1860, and 880 kg ha−1 in 1998, 1999, and 2000, respectively. There were no consistent differences in crude protein or in vitro digestible dry matter concentrations among the wheatgrasses. Crude protein concentration was higher for Russian wildrye in April and June but higher for the wheatgrasses in May. In vitro digestible dry matter was lower for Russian wildrye in May compared with the wheatgrasses. Warm‐season grasses invaded all plots over years. Western wheatgrass was most resistant to invasion. Intermediate and tall wheatgrasses were not adapted to the conditions of this study, and any further research should focus on western wheatgrass or Russian wildrye.

Evaluation of Native and Introduced Grasses for Reclamation and Production

Crested wheatgrass (Agropyron cristatum [L.] Gaertn.) and Russian wildrye (Elymus junceus Fisch.) are commonly used for reseeding in the more xeric Mixed Prairie of the Canadian prairies because they are perceived to be more productive than native species. However, they have been implicated in soil deterioration. The objectives of our study were to compare the aboveground net primary production and soil organic carbon (C) among monoculture communities of selected native grass species, crested wheatgrass, and Russian wildrye and to compare the native grass monocultures with their mixtures. In 1995, a 5-year study was initiated on Dark Brown Chernozemic (Typic Haploboroll) soil near Lethbridge, Alberta. Ten treatments consisting of monocultures of introduced and selected native species and mixtures of native species were established in a randomized complete block design with 4 replications. Aboveground net primary production and soil organic C were measured. Monocultures of 2 native species, green needlegrass (Stipa viridula Trin.) and blue grama (Bouteloua gracilis [H.B.K.] Lag. ex Steud.), were more productive than crested wheatgrass or Russian wildrye under both normal moisture and drought conditions. Monocultures of these native species also tended to be more productive than their mixtures. The western wheatgrass (A. smithii Rydb.) monoculture and the western wheatgrass-blue grama mixture experienced the greatest yield reduction as a result of drought. Treatment effects on soil organic C were not detected (P &gt; 0.05) 5 years after seeding. Soils of the June grass (Koeleria macrantha [Ledeb.] J.A. Schultes f.) community had less (P &lt; 0.05) macro-organic C than most other treatments.