Showing items related by title, author, creator and subject.

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  Characterization of Siberian wheatgrass germplasm from Kazakhstan (Poaceae: Triticeae)

  Jensen, K. B.; Asay, K. H.; Johnson, D. A.; Li, B. J. (Society for Range Management, 2000-05-01)

  Siberian wheatgrass [Agropyron fragile (Roth) Candargy] is known for its establishment and persistence on sandy soils under severe water limitations. Morphology, cytology, and forage and seed characteristics were studied on 59 accessions (JA) of Siberian wheatgrass collected on sandy soils in the desert areas of western Kazakhstan. Plants were grown at Nephi, Ut., from 1993 to 1996 and compared with the check cultivars of Vavilov and P-27 Siberian wheatgrass, and Nordan crested wheatgrass [A .desertorum (Fisch. ex Link) Schultes]. All JA-accessions were autotetraploids, 2n= 4x= 28. The most frequently observed meiotic association was 6 bivalents + 4 quadrivalents. The JA-accessions were morphologically diverse, ranging from short to tall in stature and from dark-green, glaucous to blue-green, strongly pubescent. Mean forage yield, crude protein, and dry matter digestibility were generally lower in the JA-accessions than the check varieties. Entry x year interactions were nonsignificant (P> 0.05) for all measured forage variables. Entries were significantly (P < 0.01) different for dry matter production. Seed weight of Vavilov and mean seed weight of JA-accessions were significantly (P < 0.01) greater than that for the check cultivars P-27 and Nordan. Entries that were highly pubescent had the heaviest seed and greatest capacity to emerge from a 7.6-cm planting depth. Seed yield plant -1 was significantly (P < 0.01) lower in the JA-accessions than cultivars Vavilov, P-27, and Nordan. Sufficient variations exist for seed yield, seed weight, seedling vigor, and forage yield within the JA-accessions to allow for the development of an agronomically suitable, drought tolerant Siberian wheatgrass through selection.
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  Physiological responses of 6 wheatgrass cultivars to mycorrhizae

  Jun, D. J.; Allen, E. B. (Society for Range Management, 1991-07-01)

  The physiological and morphological responses of 6 wheatgrass (Agropyron) cultivars to vesicular-arbuscular mycorrhizal inoculation were measured in the greenhouse. These included diploid, tetraploid, and hexaploid cultivars. Plants had up to 94% infection after 4 months. The 2 diploid cultivars (A. cristatum cv.'Fairway' and A. cristatum ssp. puberulum) formed infection most rapidly, and they also had significantly reduced root biomass and higher water use efficiency with infection. A hexaploid cultivar (A. cristatum from U.S.S.R.) produced significantly more tillers with inoculation, while the tetraploid A. desertorum cv. 'Nordan' had fewer tillers and wider leaves. Inoculation increased leaf phosphorus concentration in 4 of the 6 cultivars. Carbon dioxide gas exchange rate, transpiration rate, stomatal resistance, and N concentration were not significantly affected by mycorrhizal inoculation for any of the cultivars. The cultivar Nordan had the greatest number of physiological and morphological increases in response to mycorrhizal infection, while A. cristatum from Iran (hexaploid) performed most poorly in that it had reduced WUE and no apparent beneficial responses to infection. There was no relationship between ploidy level and mycorrhizal response.
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  Interplanting crested wheatgrass with shrubs and alfalfa: effects of competition and preferential clipping

  Pendery, B. M.; Provenza, F. D. (Society for Range Management, 1987-11-01)

  Planting palatable shrubs and legumes into an established stand of crested wheatgrass (Agropyron desertorum and A. cristatum) could increase forage yield and nutritional quality. Preferential grazing of the grass and legume in spring may enhance establishment of shrub seedlings. Seedlings of 3 species of shrubs (Artemisia tridentata ssp. vaseyana, Kochia prostrata, and Atriplex canescens) were transplanted into plots of crested wheatgrass using a replacement series design. Each species of shrub was grown with the grass, and with the grass and alfalfa (Medicago sativa cv. 'Ladak'); each of the 5 species was also grown in monoculture. Swards were either uncut or the grass and alfalfa were clipped while actively growing in late May and early June. Shrubs had greater current annual growth (CAG) (P is lesser than or equal to 0.001), higher relative yields (P is lesser than or equal to 0.05), lower mortality (P is lesser than or equal to 0.001), and more inflorescences (P≤0.001) in monoculture than in mixture. The grass had greater CAG in mixture than in monoculture (P is lesser than or equal to 0.05), and the grass and alfalfa had greater relative yield in mixture than in monoculture (P is lesser than or equal to 0.05). Clipping crested wheatgrass and alfalfa increased shrub CAG (P is lesser than or equal to 0.01), reduced mortality (P is lesser than or equal to 0.001), and increased the number of inflorescences (P is lesser than or equal to 0.01), but the increase in shrub CAG and flowering due to clipping was not as great as when shrubs were grown in monoculture. There were no interactions between competition and clipping (P>0.05). In terms of CAG, mortality, and flowering, A. tridentata grew better than K. prostrata, which grew better than A. canescens, but these relationships involved complex interactions. The contribution of shrubs to the biomass in mixture was minor; although alfalfa dominated three-way mixture yields, the grass also made a substantial contribution. Since competition was more important in determining shrub response than clipping and the 2 effects were independent, it is probably more important to reduce interspecific competition than to modify grazing practices when planting shrubs in a crested wheatgrass stand.