Digital Commons Network^™

Patterns Of Development And Nitrogen Reserves Mobilization During Regrowth Of Defoliated Clover, F. Le Dily, E. Goulas, P. Lainé, E. Le Deunff

IGC Proceedings (1977-2023)

Contribution of nitrogen reserves to regrowth following defoliation was studied in white clover plants (Trifolium repens) according to the morphological pattern of differentiation of the aerial parts during the same period. Low temperature and short day lengths were used as a pre-treatment in order to increase branching and enhance new sites of leaf production during a further 25 d period of regrowth. Pre-treated plants exhibited a large reduction in leaf area largely counterbalanced with a high increase in leaf pool size during the first 10 d of regrowth. The mobilization of nitrogen reserves during regrowth of defoliated clover …

Resistance To Drought In Shore Elurope (Aeluropus Litoralis) And Weeping Alkaligrass (Puccinellia Distans), Mohammad Jafari, A. G. Firouzabadi

IGC Proceedings (1977-2023)

Two rangeland grass species, Shore Elurope (Aeluropus litoralis) and Weeping Alkaligrass (Puccinellia distans) were studied. The research was done under a split plot experiment and completely randomized design. Plants were grown under two irrigation treatments (seven and fourteen day periods of irrigation treatments). Morphological response included determination of wilting percentage, leaf water potential, production of yield, root dry weight, weight ratio of root/stem and finally total dry weight of species. Anatomical studies included leaf descriptive structure such as comparison of stomata and their density in area unit, study of vascular structure, mesophyl tissues and epiderm. Results …

Analysis Of Rock Varnish From The Mojave Desert By Handheld Laser-Induced Breakdown Spectroscopy, Russell S. Harmon, Daria Khashchevskaya, Michelle Morency, Lewis A. Owen, Morgan Jennings, Jeffrey R. Knott, Jason M. Dortch

Faculty, Staff, and Affiliated Publications--KGS

Laser-induced breakdown spectroscopy (LIBS) is a form of optical emission spectroscopy that can be used for the rapid analysis of geological materials in the field under ambient environmental conditions. We describe here the innovative use of handheld LIBS for the in situ analysis of rock varnish. This thinly laminated and compositionally complex veneer forms slowly over time on rock surfaces in dryland regions and is particularly abundant across the Mojave Desert climatic region of east-central California (USA). Following the depth profiling examination of a varnished clast from colluvial gravel in Death Valley in the laboratory, our in situ analysis of …

Allelopathic Influence Of Eragrostis Curvula Water Extract On Seed Germination And Seedling Growth Of Two Other Species, R. W. Coelho, R. E. Schmidt

IGC Proceedings (1977-2023)

Weeping lovegrass (Eragrostis curvula Schrad. Nees) is a very agressive tropical species and does not grow well with other species. This study was set up to investigate the allelopathic effect of various extract concentrations of weeping lovegrass on seed germination of white clover (Trifolium repens L.) and bentgrass (Agrostis stolonifera L.) and the seedling development of white clover. Labotatory and growth chamber studies were conducted. Extract concentrations of 13.6, 27.2, 40.8, 54.4, and 62.0 g/100mL of water were studied. Treatments were arranged in a completely ramdomized design with three replications. The allelopathic effect of weeping lovegrass was …

Effect Of Aging In Tillers Of Panicum Maximum On Leaf Elongation Rate, D. D. Carvalho, C. Matthew, J. Hodgson

IGC Proceedings (1977-2023)

Two cultivars of Guinea grass (P. maximum, Jacq.), Mombaça and Tanzânia, were cultivated in five litre pots, as single plants, in a green house. Plants were subjected to three defoliation levels (100, 200 and 400 mm height) for five successive monthly harvests. The experimental design was a 3x2 randomised block with five replicates. Three types of tiller (main, primary and secondary) were selected, at random, on each plant and leaf elongation rate (LER) above cutting height was measured, weekly, between harvests. There were significant differences (P < 0.05) in LER between tiller types in cv. Mombaça in all periods, but only in period two in cv. Tanzânia. In the last period tillers were classified, at random, as old (over four months age) mature (between two and four months) and young (between one and two months). Old tillers had a lower (P < 0.05) LER than the other two categories in both cultivars and lower (P < 0.05) SLA (specific leaf area) in Mombaça.

Dormant Bud Development In Phalaris Aquatica L., Brendan R. Cullen, P. E. Quigley, D. F. Chapman

IGC Proceedings (1977-2023)

The formation of dormant buds is critical to the summer survival of phalaris (Phalaris aquatica L.) in pastures. Dormant buds are formed on the base of reproductive tillers as they develop in spring. This project aimed to determine the seasonal pattern of dormant bud development and the influence of grazing management on bud dynamics. Approximately three buds per reproductive tiller were formed in the spring and early summer period. These buds responded to summer rainfall, with one third of buds becoming active following a 15-mm rainfall event in mid summer. In the following growing season, on average, 1.5 buds …

Tillering Dynamics Of Panicum Maximum Jacq. Cv. Tanzania-1 After Grazing, Rodrigo A. Barbosa, Domicio Nascimento Jr., Valéria P. B. Euclides, A. J. Regazzi, D. M. Fonseca

IGC Proceedings (1977-2023)

Tillering dynamics and tiller dry matter weight from Tanzania grass (Panicum maximum cv. Tanzania-1) were evaluated in two post-grazing stubbles (High Post-grazing Stubble – HPS-3.6 t of DM/ha and Low Post-grazing Stubble – LPS-2.3 t of DM/ha). There was no difference between post-grazing stubbles for decapitated axillary and basal remainder and new axillary tillers. The LPS presented greater number of new basal tillers. The rate of appearance of new basal and axillary tillers decreased with time after grazing. There were differences between the treatments on tiller dry matter weight, and greater values were found in the high post-graze stubble.

Flowering Distribution Pattern In White Clover Cultivars, B. S. Rosso, E. M. Pagano, P. Rimieri

IGC Proceedings (1977-2023)

A trial was carried out at Pergamino Agricultural Experimental Station to examine the distribution pattern and the profuseness of inflorescence production of white clover (Trifolium repens L.). The treatments were 16 cultivars (Churrinche, El Lucero MAG, Bayucuá, Estanzuela Zapicán, Lucero Plus Inta, Haifa, California, Ladino Gigante Lodigiano, Dubrava, Susi, Merwi, Blanca, Sonja, Espanso, Nora, S 184) of different origins and leaf size. The experimental design was a lattice with four replications. Southamerican cultivars showed a similar distribution pattern and had the highest inflorescence production. They also flowered earlier than foreign cultivars, except Haifa. Some of the cultivars evaluated did …

Breeding Italian Annual Ryegrass For Tolerance To Pythium Ultimum, L. R. Nelson, I. J. Pemberton, G. R. Smith

IGC Proceedings (1977-2023)

This study was conducted in an attempt to improve tolerance of annual ryegrass to Pythium ultimum Trow. Improved tolerance of ryegrass as measured in laboratory experiments was confirmed in greenhouse studies. This tolerance was defined as improved emergence and increased root length of seedlings in the presence of P. ultimum, using rolled germination paper in the laboratory, and sand in the greenhouse. Further experimentation will be required to determine usefulness of this selected trait under field conditions.

Suitable Seed Harvesting Time For Six Grass Species, Hossein Arzani, A. Fakhireh

IGC Proceedings (1977-2023)

Determination of the best period of seed harvesting was considered. Six grass species were selected. The research was conducted in three stations of Alborz, Sirachal and Homand Absard. According to maturing stages, seed collection for measuring seed water content (moisture content), weight of 1000 seeds and germination percentage has been done. The result showed that there were significant differences between harvesting time on seed germination for all species in all regions. Moisture content, germination rate, weight of 1000 seeds and seed shedding were important characteristics for determination of suitable seed harvesting time.

Effect Of Nitrogen Fertilizer On Reproductive Tiller Development In Perennial Ryegrass, I. Bahmani, E. R. Thom, C. Matthew, G. Lemaire

IGC Proceedings (1977-2023)

The objective of this study was to compare reproductive tiller development in two ryegrass (Lolium perenne L.) cultivars, when fertilized with nitrogen. Plots of the cultivars ‘Grasslands Ruanui’ and ‘Ellett’ ryegrass were sown in April 1996. Half of each plot received nitrogen fertilizer (30 kg N/ha) after each grazing by dairy cows from September 1996 to May 1997 and from October 1997 to April 1998. Ryegrass tiller dynamics was monitored from September 1996 to March 1998. The proportion of reproductive tillers in the total tiller population was higher, on average, over the first flowering period (October 1996 to January …

Impact Of Nitrogen Rate In Conventional And Organic Production Systems On Yield And Bread Baking Quality Of Soft Red Winter Wheat, Ammar Al-Zubade, Timothy D. Phillips, Mark A. Williams, Krista L. Jacobsen, David Van Sanford

Plant and Soil Sciences Faculty Publications

Soft red winter wheat (SRW) is characterized by high yield and relatively low protein content. In Kentucky, there is growing demand from local artisan bread bakers for regionally produced flour, requiring production of grain with increased protein content and/or strength. The objective of this two-year field experiment was to evaluate the effect of nitrogen (N) management on five cultivars of winter wheat on yield and bread baking quality traits of modern and landrace SRW cultivars (Triticum aestivum L.). All five cultivars were evaluated using two N application rates in conventional and organic production systems. All traits measured were significantly …

Tropical Legumes To Augment Forage Yield In The Eastern Caribbean, E. Valencia, M. B. Adjei

IGC Proceedings (1977-2023)

Little information is available on the contribution of tropical legumes to forage yield in the eastern Caribbean. This study assessed the effects of three grazing cycles (GC; 5, 10 and 15-wk) on seasonal dry matter (DM) yield of binary mixtures of the tropical legumes glycine (Neonotonia wightii) and desmanthus (Desmanthus virgatus) with “Bambatsi” (Panicum coloratum) and “Mottgrass” (Pennisetum purpureum Shum.). Plant responses were assessed by mob-grazing with sheep (12-24 hrs; to average stubble height of 15-cm) for each GC. Grazing cycles affected yield of both the legume and grass component (P< 0.05). At GC of 5-weeks, forage DM ranged from 1.5-2.0 Mg ha^-1 in …

Yield And Forage Quality In Alfalfa-Weeping Lovegrass Mixtures, H. Laborde, R. E. Brevedan, M. A. Varillas, M. N. Fioretti

IGC Proceedings (1977-2023)

Little is known about the relative performance of weeping lovegrass in mixtures with alfalfa. Our objective was to compare the productivity and forage quality of monocultures and binary mixtures of the species. Mixtures always gave higher yields than any of the monocultures and the highest was obtained in the mixture with the largest proportion of alfalfa. In the second year weeping lovegrass N concentration in the mixtures were higher than in monoculture. Weeping lovegrass did not affect the alfalfa N concentration. There was not differences in the NDF, for between these species.

Forage Quality Of Mixtures Of Bromus Wildenowii And B. Parodii Influenced By Nitrogen Fertilization Or Alfalfa Interseeding, S. Abarza, R. E. Brevedan, H. Laborde

IGC Proceedings (1977-2023)

Under good soil fertility conditions, Bromus wildenowii Kunth and Bromus parodii Covas et Itria are two high producing forage grasses. The objective of this study was to evaluate the effect of nitrogen fertilization or the association with alfalfa (Medicago sativa L) on yield and forage quality of mixtures of both grasses during the establishment year. Nitrogen fertilizer (300 kg ha^-1) was broadcasted in three 100 kg N dosis. Nitrogen fertilization or alfalfa intercropping did not increase dry matter yield. Tiller density and crude protein content of grass forage were increased by nitrogen application. Intercropped alfalfa increased N …

Intake And Yield Of Cynodon Nlemfuensis Alone And Associated With Leucaena Leucocephala Grazed By Sheep, J. G. Escobedo-Mex, Luis Ramírez-Avilés, Juan C. Ku-Vera

IGC Proceedings (1977-2023)

The objective of the present study was to determine dry matter intake (DMI) and the forage yield of green dry matter (GDM) of star grass (Cynodon nlemfuensis) alone and associated with Leucaena leucocephala cv. Perú grazed by sheep. The experimental treatments were: Systems T1) Star grass alone, and T2) Star grass + L. leucocephala. These treatments were evaluated during three seasons (i.e. Late-rainy, Dry and Rainy seasons). The availability of forage was lower (P < 0.0001) in T1, 2543 kg GDM/ha, than with T2, 3092 kg GDM/ha. Green dry matter in the rainy season was greater (P < 0.0001), with 3910 kg GDM/ha, than in the late-rainy and dry seasons, 2492 and 2052 kg GDM/ha, respectively. DMI was 5.9 and 7.6 g DM/kg of LW ^0.75/hour for the T1 and T2, respectively (P < 0.0001). DMI during the rainy season was lower (P < 0.01) than that of the dry and late-rainy seasons, 6.2, 6.4 and 7.5 g DM/kg LW^0.75/hour, respectively. The association C. nlemfuensis-L. leucocephala increased the availability of …

Allelopathy Of Panicum Maximum Jacq. Cultivars On Tree And Shrub Forage Legumes: Greenhouse Estimate, A. R. P. Almeida, T. J. D. Rodrigues

IGC Proceedings (1977-2023)

The available information about allelopathic effects of the genus Panicum on tropical forage legumes is scarce and inconclusive. Based on this fact this research was carried out, under greenhouse conditions to evaluate potential allelopathic effects of aqueous extracts (0,10 and 20%) of three cultivars of Panicum maximum Jacq. cv. Mombaça, cv. Aruana and cv. Tanzânia-1 on three forage legumes, Leucaena leucocephala (Lam.) de Wit. (leucaena), Cajanus cajan (L.) Millsp. cv. Kaki (pigeon pea) and Sesbania sesban (L.) Merr. (sesbania) seeking for mixed grasses and legumes pastures. The following characteristics were evaluated: emergence porcentage, speed of germination index, root density, dry …

Tillage Systems In The Establishment Of Pastures In Argentinian Subhumid Area, H. Pagliaricci, C. Saroff, A. Ohanian, T. Pereyra

IGC Proceedings (1977-2023)

The effect of three tillage systems on the number of plants produced and forage production of a pasture the first year of establishment was assessed in this experiment. The components of the pasture were alfalfa (Medicago sativa L.), tall fescue (Festuca arundinacea Shreb), orchard grass (Dactilys glomerata L), and prairie grass (Bromus unioloides). Treatments were three tillage systems: conventional tillage (CT), reduced tillage (RT), and direct sowing (DS). Sowing was performed with (NI) and without fertilizers (N0) in each treatment. A split-plot experimental design with two repetitions was used, with tillage being the main factor …

Correlation Between Yield Of Forage Legumes In Grass Mixtures And Accumulation Of Soil Mineral Nitrogen In Sweden, Magnus A. Halling, David Scholefield

IGC Proceedings (1977-2023)

Soil mineral N and DM yield of five forage legume species were investigated in field experiments at two sites in Sweden, established 1997. The species studied were: red clover (Trifolium pratense L.), lucerne (Medicago sativa L.), white clover (Trifolium repens L.), galega (Galega orientalis Lam.) and lotus (Lotus corniculatus L.), all grown in grass-legume mixed swards. No nitrogen was applied to the legumes. Results from two years of ley (1998 and 1999) are presented. Correlation was found between accumulated mineral N in the soil in the autumn and the total seasonal DM yield of the …

Introduction Of Forage Legumes Into Pastures Of Three Different Grasses, Maria T. Colozza, Joaquim C. Werner, Luciana Gerdes, E. A. Schamass, J. C. T. Freitas

IGC Proceedings (1977-2023)

It was evaluated the introduction of a mixture of calopo, galaxia, perennial soybean, guata and stylo broadcsted into marandu, setaria and tanzania half-plots already established in three cafeterias, each one located inside a paddock of each grass. The legumes were seeded in the end of the Spring (12/07/98), after the plots had been cut down and fertilized. The cafeterias were grazed intermittently by buffaloes maintained in the three paddocks. The occurrence of the five legume plants was avaluated by countings (#/m²) effected in the middle of Autumn, Winter and Spring of 1999 and Summer of 2000. Along with …

Allelopathy Of Panicum Maximum Jacq. Cultivars On Tree And Shrub Forage Legumes: Tolerance Index, A. R. P. Almeida, T. J. D. Rodrigues

IGC Proceedings (1977-2023)

The objective of this work was to evaluate the tolerance of three forage legumes (Leucaena leucocephala (Lam.) de Wit., Cajanus cajan (L.) Millsp. cv. Kaki and Sesbania sesban (L.) Merr.) to the allelopathic effects of three cultivars of Panicum maximum Jacq. (cv. Mombaça, cv. Aruana and cv. Tanzânia-1), under greenhouse conditions. The root and shoot tolerance indexes were calculated using the data of dry mass of roots and shoots of plants cultivated in pots and moistened with water or aqueous extracts (0,10 and 20%) of the cultivars of P. maximum. The results indicated that: a) the root tolerance …

Compatibility Of Kura Clover And Cool Season Grass Mixtures In Michigan, P. Jeranyama, R. H. Leep, T. Dietz

IGC Proceedings (1977-2023)

Kura clover (Trifolium ambiguum Bieb.) is an alternative forage legume for rotational grazing in cool-season grass mixtures. However, compatibility with cool-season grasses is unknown. Seven cool-season perennial grasses were seeded into Kura clover in a rotational grazing experiment. The objectives of this study were to evaluate botanical composition, forage yield and quality of binary mixtures of cool-season grass with Kura clover. Field studies were conducted on a Nester (fine sandy loam) soil at Lake City Experiment Station, Lake City, MI. Botanical compositions in the first year of the study heavily favored grasses (avg. 74%) and Kura clover accounted for …

Forage Legume Presence And Grazing Intensity Effect On Nitrogen Dynamics In Brachiaria Pastures In The South Of Bahia, Brazil, R. B. Cantarutti, R. Tarré, R. Macedo, C. De P. Rezende, J. M. Pereira, E. Ferreira, B. J. R. Alves, S. Urquiaga, R. M. Boddey

IGC Proceedings (1977-2023)

The objective of this study performed in the Atlantic forest region of the South of Bahia (Brazil) was to examine the influence of the presence of the forage legume Desmodium ovalifolium in pastures of Brachiaria humidicola on the nitrogen recycled through plant litter over stocking rates of 2, 3 and 4 head ha^-1. The results demonstrated that the presence of the D. ovalifolium in the pasture significantly increased the protein content of the associated Brachiaria grass, and the rate and quantity of N recycled through the litter pathway. While had no significant increase in animal weight gain due …

Production Of Orchard-Grass Cultivars (Dactylis Glomerata) In Mixtures With Alfalfa (Medicago Sativa), Under Grazing Conditions, R. A. Barbarossa, D. P. Miñón

IGC Proceedings (1977-2023)

In the Lower Valley of the Río Negro (northern Patagonia, Argentina), six binary mixtures of orchard-grass (Dactylis glomerata) cultivars (Porto, Currie, Filox, a Local ecotype, Pergamino El Cencerro MAG) and alfalfa (Medicago sativa) Monarca SP INTA, were tested under grazing and irrigation. Mixtures were evaluated during three growing seasons (96/97; 97/98 and 98/99). Total forage production of mixtures and botanical composition was measured (orchard-grass cultivars and alfalfa). Porto, Currie, Filox, Local and Cencerro cultivars reached similar yield, while Amba produced less forage (p< 0.05). Mixture yield showed no significant difference, except Porto + alfalfa, which was lower (p< 0.05). The grass was higher in spring (1^st grazing) of three growing seasons. Orchard-grass + alfalfa showed highest dry matter …

The Impact Of The Human Papillomavirus Vaccine On High-Grade Cervical Lesions In Urban And Rural Areas: An Age–Period–Cohort Analysis, Jaimie Z. Shing, Alicia Beeghly-Fadiel, Marie R. Griffin, Rachel S. Chang, Staci L. Sudenga, James C. Slaughter, Manideepthi Pemmaraju, Edward F. Mitchel, Pamela C. Hull

Behavioral Science Faculty Publications

Disparities in human papillomavirus (HPV) vaccination exist between urban (metropolitan statistical areas (MSAs)) and rural (non-MSAs) regions. To address whether the HPV vaccine’s impact differs by urbanicity, we examined trends in cervical intraepithelial neoplasia grades 2 or 3 and adenocarcinoma in situ (collectively, CIN2+) incidence in MSAs and non-MSAs among Tennessee Medicaid (TennCare)-enrolled women aged 18–39 years and among the subset screened for cervical cancer in Tennessee, United States. Using TennCare claims data, we identified annual age-group-specific (18–20, 21–24, 25–29, 30–34, and 35–39 years) CIN2+ incidence (2008–2018). Joinpoint regression was used to identify trends over time. Age–period–cohort Poisson regression models …

International Grassland Congress Outlook – A Historical Review And Future Expectations, L. R. Humphreys

IGC Proceedings (1977-2023)

Features of the history of the International Grassland Congress are mentioned. Aspects of a number of failed themes in grassland science are described with respect to molecular biology, intensive systems of ruminant production, carbohydrate use in plant growth, plant succession and range condition, and stocking method. Future expectations are focused on meeting a balance of objectives, maintaining reductionist science, taking new initiatives in plant improvement and in the development of animal production systems, and reducing barriers to international trade. The adoption of grassland science depends upon the growth of new learning, especially through cyclical interaction between scientists and farmers.

Production Potential Of South America Grasslands, G. E. Maraschin

IGC Proceedings (1977-2023)

Grasslands exist all over the world under a wide range of climates, soil types, topography conditions and seasonality. The South America grasslands cover a wide range of ecosystems and vegetaion types, going from desert areas to steppes, subhumid temperate, subtropical and tropical savannas embodying also portions of the tropical rain forest environment, and represent one of the Earth’s largest expanses of natural rangelands (Oesterheld et al., 1992). They represent developed ecosystems requiring acquaintance to accept sound agronomic and ecological activities. The diversity of vegetation determined by the latitudes 6^oN, down to the southern most tip of the continent …

Grassland Production And Management – Trends And Perspectives For The 21St Century, John Hodgson

IGC Proceedings (1977-2023)

The XIX International Congress is set in a time of unprecedented change, with increasing uncertainty about the long-term sustainability of established systems of land use. The major threats are the continuing rapid increase in the human population of the world, the pressure on land resources to meet food requirements, the effects of global warming on climate stability, and the consequence of these factors on land resource stability and food production potential. Overlying these threats is the impact of the global economy on land use policies.

Projections made at the XVIII International Grassland Congress in 1997 suggested that food production could …

Equine Influenza Virus And Vaccines, Fatai S. Oladunni, Saheed Oluwasina Oseni, Luis Martinez-Sobrido, Thomas M. Chambers

Veterinary Science Faculty Publications

Equine influenza virus (EIV) is a constantly evolving viral pathogen that is responsible for yearly outbreaks of respiratory disease in horses termed equine influenza (EI). There is currently no evidence of circulation of the original H7N7 strain of EIV worldwide; however, the EIV H3N8 strain, which was first isolated in the early 1960s, remains a major threat to most of the world’s horse populations. It can also infect dogs. The ability of EIV to constantly accumulate mutations in its antibody-binding sites enables it to evade host protective immunity, making it a successful viral pathogen. Clinical and virological protection against EIV …

Mechanisms Of Smoothened Regulation In Hedgehog Signaling, Jie Zhang, Zulong Liu, Jianhang Jia

Markey Cancer Center Faculty Publications

The seven-transmembrane protein, Smoothened (SMO), has shown to be critical for the hedgehog (HH) signal transduction on the cell membrane (and the cilium in vertebrates). SMO is subjected to multiple types of post-translational regulations, including phosphorylation, ubiquitination, and sumoylation, which alter SMO intracellular trafficking and cell surface accumulation. Recently, SMO is also shown to be regulated by small molecules, such as oxysterol, cholesterol, and phospholipid. The activity of SMO must be very well balanced by these different mechanisms in vivo because the malfunction of SMO will not only cause developmental defects in early stages, but also induce cancers in late …