Physical Sciences and Mathematics Commons^™

Microcalorimeter As A Biologic Activity Monitor For The Study Of Brachiaria Brizantha Seed Germination Process, M. A. Barboza, P. L. O. Volpe, R. Usberti, J. F. G. Faigle, R. H. Aguiar

IGC Proceedings (1993-2023)

Calorimetry helps better understanding of biological processes (Calvet & Prat, 1963). Very sensitive thermal sensors and microcalorimeters allow real time investigation and monitoring heat production of seed germination but few experiments have been performed in this area (Sigstad & Prado, 1999). Moreover, experimental procedures correlating germination phenomena and chemical thermodynamics are exceptional (Barboza, 2002). One can detect calorimetrically the heat flow produced during seed germination and compare the results with data recorded using standard germination methodology (ISTA, 1985). Seed germination and the biomass increase respiration and determination of the energy involved aids understanding of the energetic cycle involved. This work …

Effect Of Defoliation Interval On Regrowth Of Leaves And Roots, And Tiller Number Of Cocksfoot Plants, L. R. Turner, D. J. Donaghy, P. A. Lane

IGC Proceedings (1993-2023)

The key to defoliation management for optimal production and persistence of pasture lies in the use of a physiological basis for defoliation interval (specific to plant type), as opposed to a regime based on time or the height of herbage. The full expansion of a particular number of leaves/tiller is a useful plant-related indicator of optimal defoliation timing. Leaf regrowth stage ('leaf stage') reflects the stage of plant recovery from defoliation as regards plant energy levels (Fulkerson & Donaghy, 2001). The level of water-soluble carbohydrate (WSC) reserves in grass tiller bases influences the rate of regrowth after defoliation, affecting the …

Morphogenetic Characteristics Of Panicum Maximum Cv. Aruana Subjected To Five Defoliation Stubble Heights And Two Frequencies, D. D. Carvalho, Alessandra A. Giacomini

IGC Proceedings (1993-2023)

Tillers in grass swards are subject to size density compensation and this mechanism has been observed to follow the -3/2 self thinning rule. This theory assumes that tiller components (leaf lamina and stems) have a constant geometry as the sward is taller or shorter. In a re examination of this rule (SackvilleHamilton et al., 1995) observed that in grass swards the slope can be different from -3/2 depending on the extremes of defoliation (Hernandez-Garay et al., 1999). Therefore, the dimensionless measure, R (ratio tiller leaf area : volume) was proposed to isolate the tiller geometry component from the …

Long Term Tiller Population Dynamics In Swards Of Grasses With Contrasting Persistence Strategy, F. Gastal, C. Matthew

IGC Proceedings (1993-2023)

The lifespan of individual grass tillers usually does not exceed 12-15 months, because of death of tillers after floral induction and development, or randomly from disease or other factors. Persistence of the tiller population over several years, and associated long term maintenance of the sward, thus depends on the rate of turnover of individual tillers. This study aimed to characterise seasonal and management conditions critical for tiller turnover and its components, tiller birth and tiller death. Two grasses were investigated: Festuca arundinacea and Lolium multiflorum, having high and low persistence, respectively.

The Effect Of Blue Light On Leaf Growth And Plant Development In Two Morphologically Contrasted Perennial Ryegrass Genotypes: Cellular Basis And Ecological Implications, F. Gastal, A. Verdenal, P. Barre

IGC Proceedings (1993-2023)

Several major plant responses to competition for light are determined by responses to light signals, in particular to red/far-red ratio (R/FR) and blue light, besides responses mediated through photosynthesis and carbon assimilation (Gautier et al., 1999). These responses to light signals allow plants to react to the presence of neighbours and to anticipate the impact of light competition on photosynthesis. The objective of the study was to evaluate the impact of blue light on leaf growth and its cellular basis, on two short and long leaved populations (FC and FL respectively), which were shown to have different competitive ability …

Shading Effect On Production And Protein Concentration Of Dactylis Glomerata And Agrostis Tenuis, A. Rigueiro-Rodríguez, S. Rodríguez-Barreira, M. R. Mosquera-Losada

IGC Proceedings (1993-2023)

Silvopastoral systems make compatible livestock and timber production and provide important advantages from economic and ecological points of view (Sibbald, 1996). Around one million ha of new afforested areas promoted by the EU Common Agricultural Policy have been established in the last decade, that can be used as potential silvopastoral system areas. Pasture production is usually reduced in dense stands as trees grow up due to the light interception by the tree crown, but the radiation reaching the soil will depend on the tree type and this will affect herbaceous species composition and development. The aim of this work was …

Net Photosynthesis Rate And Chlorophyll Content Of Caucasian And White Clover Leaves Under Different Temperature Regimes, A. D. Black, R. J. Lucas, D. J. Moot

IGC Proceedings (1993-2023)

In spring and summer in intensive temperate pastures, Caucasian clover (Cc) (Trifolium ambiguum) has higher dry matter (DM) production rates than white clover (wc) (Trifolium repens) (Black et al., 2003). An examination of the physiological basis for these differences can provide a greater insight into the suitability of Cc for inclusion in temperate pastures. Specifically, leaf photosynthesis rate is a major driver of seasonal growth and is strongly regulated by temperature and chlorophyll content. This study aimed to compare the net photosynthesis rate (Pn) and chlorophyll content of Cc and wc leaves under different temperature …

Prediction Of Canopy Photosynthesis For Cocksfoot Pastures Grown Under Different Light Regimes, P. L. Peri, D. J. Moot, D. L. Mcneil

IGC Proceedings (1993-2023)

Plants in field environments can experience frequent fluctuations in irradiance from full sun to shade caused by cloud cover, overstory shading (e.g. silvopastoral systems) and within canopy shading. Research with widely spaced radiata pine (Pinus radiata D. Don) has suggested that due to its shade tolerance cocksfoot (Dactylis glomerata L.) is a suitable grass for silvopastoral systems. However, there is limited explanation of the physiological basis for the responses, and consequently no predictive capacity. This limits the application of results to environments, sites and seasons outside of those in which they were measured. The objectives of this study …

Effect Of Three Legumes Containing Different Condensed Tannin Concentrations On The In Vitro Formation Of The Pastoral Flavour Compound; Skatole, N. M. Schreurs, M. H. Tavendale, G. A. Lane, T. N. Barry, W. C. Mcnabb

IGC Proceedings (1993-2023)

Feeding legumes, such as white clover (Trifolium repens), results in higher intakes and increased animal production compared to grasses (Ulyatt, 1981). Skatole is produced in the rumen from plant protein fermentation and is associated with undesirable pastoral flavours in meat (Young et al. 2002). Feeding white clover causes a greater skatole concentration in the rumen compared to perennial ryegrass (Lolium perenne) or Lotus corniculatus, as the protein in white clover is highly soluble and rapidly degraded (Schreurs et al., 2004). The condensed tannins (CT) in Lotus species slow protein degradation in the rumen (Aerts …

Shearing Strength And Chemical Composition In The Selection For Quality In Brachiaria Brizantha, Cacilda B. Valle, F. E. Torres, B. Lempp

IGC Proceedings (1993-2023)

Selection of quality pasture forages for productivity, nutritive value and animal performance require long-term, expensive trials. Simpler and accurate techniques to detect quality differences among genotypes have been proposed (Mackinnon et al., 1988; Hughes et al., 2000). This paper discusses the use of shearing strength in Brachiaria brizantha ecotypes to correlate physical traits with chemical composition: the objective being the identification of cultivars of improved quality forage suitable to the savannas of Brazil.

Meiotic Arrest Compromises Pollen Fertility In An Interspecific Hybrid Between Brachiaria Ruziziensis X Brachiaria Decumbens (Gramineae), M. S. Pagliarini, Cacilda B. Do Valle, A. B. Mendes-Bonato, C. Risso-Pascotto

IGC Proceedings (1993-2023)

Disruptions in meiosis, development of the free microspores, microspore mitosis, pollen differentiation or anthesis can result in male-sterile plants (Glover et al., 1998). An understanding of the meiotic process is pivotal to work on reproduction, fertility, genetics and breeding in plants, with serious implications in crop production (Armstrong & Jones, 2003). Some African species of Brachiaria are the most important for pastures in the American tropics due to good adaptation and production. Artificial hybridization is underway in Embrapa to improve production, quality and insect resistance (Valle & Miles, 2001). For a cultivar to be successfully adopted good seed production …

Analysis Of Genomic Affinity Between Brachiaria Ruziziensis And B. Brizantha Through Meiotic Behaviour, Cacilda B. Do Valle, M. S. Pagliarini, A. B. Mendes-Bonato, C. Risso-Pascotto

IGC Proceedings (1993-2023)

Genetic divergence between polyploid hybrids is displayed in chromosome pairing and in the rate of chromosome elimination due to differences in cell cycle between the two combined genomes (Sundberg et al. 1991). In Brachiaria, a genus of African grasses reaching continental proportions as a tropical pasture in Latin America, genome analysis has never been performed. The majority of accessions in this genus is polyploid and apomictic, which restricts breeding. The relative ease of obtaining fertile interspecific hybrids once ploidy barriers are overcome (Pereira et al. 2001) confirms the phylogenetic proximity among B. ruziziensis, B. decumbens and …

The Economic Benefit Of Increased Yield And Digestibility In A Perennial C4 Grass, R. Mitchell, K. P. Vogel, G. Sarath

IGC Proceedings (1993-2023)

Big bluestem (Andropogon gerardii Vitman) is a perennial C₄ grass native to the North American tallgrass prairie (Weaver, 1954). It provides productive, high quality forage during late spring and summer in the Great Plains, USA (Mitchell et al., 1994). Increasing forage yield and digestibility can increase livestock performance and grassland profitability (Casler & Vogel, 1999). This study aimed to compare the economic value of 2 big bluestem strains developed by 3 generations of breeding for increased forage yield and digestibility with the base populations from which they were derived.

Growth Characteristics Of Superior Lines Of Zoysia Grass (Zoysia Japonica) And Development Of Its Dna Markers, Y. W. Rim, K. Y. Kim, M. J. Kim, B. R. Sung, Y. C. Lim, E. S. Chung

IGC Proceedings (1993-2023)

Demand for turf grass has steadily increased for recreation and sport fields after the 2002 Korea-Japan World Cup in Korea. Zoysia grass has the advantage of easy management, including low water and fertiliser requirement, but has limitations such as low recovery, low shoot density and short green period (Kim et al., 1999). Objectives of this research were to select superior lines in the collected clones, compare the superior lines of zoysia grass with other standard cultivars for growth characteristics and to develop the DNA markers of superior lines.

Quality Legume-Based Forage Systems For Contrasting Environments: Cost Action 852, A. Helgadottir, John Connolly, M. Fothergill, R. P. Collins, Claudio Porqueddu, Andreas Lüscher, M. T. Sebastia, Michael Kreuzer, M. Wachendorf

IGC Proceedings (1993-2023)

Agricultural systems that reduce environmental degradation, sustain agricultural productivity and economic viability, maintain stable rural communities, enhance the quality of life and respond to increasing demand for livestock products are promoted in developed countries. Though major challenges exist, forage legumes, adapted to a wide range of soil types, climatic conditions and management systems, will become increasingly important components of sustainable agricultural production systems in Europe. Temporal and spatial variation in legume performance often occurs. Compared to pure grass systems, legume-based systems may lead to increased N losses. To what extent ruminants can use the protein from forage legumes, and whether …

Higher Yield And Fewer Weeds In Four-Species Grass/Legume Mixtures Than In Monocultures: Results From The First Year At 20 Sites Of Cost Action 852, Laura Kirwan, Gilles Bélanger, J. A. Finn, M. Fothergill, Bodil E. Frankow-Lindberg, R. Garcia-Sarrion, A. Ghesquiere, P. Golinski, A. Helgadóttir, M. Jørgensen, Z. Kadžiuliene, D. Nyfeler, P. Nykänen-Kurki, G. Parente, V. Vasileva, R. Collins, J. Connolly, Andreas Lüscher, Claudio Porqueddu, M. T. Sebastià

IGC Proceedings (1993-2023)

Utilisation of grass/legume mixtures instead of grass monocultures is a sensible alternative for low input, efficient agricultural systems that reduce production costs, promote environmental policy and maintain a living countryside. Consequently, widely adapted forage legumes will become increasingly important. Instability of simple grass / legume mixtures with only one grass and one legume species is a major problem (Wachendorf et al., 2001). An experiment was established in 39 sites in Europe, Australia and Canada within COST Action 852 to: (1) assess the benefits of grass / legume mixtures in terms of forage production, (2) test whether the combination of …

Adaptation, Compatibility And Acceptability Of Grass-Legume Pastures In The Andean Region Of Colombia, E. Cárdenas, E. Castro

IGC Proceedings (1993-2023)

In Colombia, the specialised dairy production system is located in the high altitude Andean region. Its main feed resources are pure stands of Pennisetum clandestinum or/and Lolium spp. Nevertheless, the present market conditions require highly competitive and quality forages year round. These forages should be produced with low inputs (irrigation, fertilisers and agrochemicals) and be resistant to pests and diseases. The objective of this research was to evaluate the adaptation, compatibility and acceptability of introduced forage species for sustainable pasture management.

New Cultivars For High Quality, Persistent Legume-Grass Pastures In The Southern Usa, J. H. Bouton

IGC Proceedings (1993-2023)

In the southern USA one cannot depend on perennial legume-grass pasture systems to have persistently high nutritive quality. 'Jesup' tall fescue, a cultivar with better persistence in the region than 'Kentucky 31', was re-infected with a non-ergot alkaloid producing strain of the Neotyphodium coenophialum fungal endophtye (MaxQ^TM) and found to give persistence equal to Jesup with its endemic strain (E+), but without animal toxins (Bouton et al., 2002). 'Durana' white clover (Bouton et al., 2004) was developed from regional ecotypes of Trifolium repens f. hollandicum germplasm and found to improve animal performance in both E+ and …

Seed Productivity Of Festulolium And Lolium X Boucheanum Varieties, Iveta Gutmane, Aleksandr Adamovich

IGC Proceedings (1993-2023)

Hybrid ryegrasses are intermediate lines between perennial ryegrass and Italian ryegrass as regards growth parameters, productivity and resistance. Good quality and digestibility of forage and higher yield are the main advantages of hybrid ryegrass over perennial ryegrass. Climatic conditions in the Baltic States and North Europe are not favourable enough for ryegrass cultivation but Festulolium is a prospective forage crop for this area (Nesheim, 2000, Adamovich, 2003). Ryegrasses, including hybrid ryegrasses, surpass Festulolium in forage quality. However, Festulolium persistance (resistance, winter-hardiness and, thus, high productivity) are noteworthy. Due to yield quality and competitive productivity, Festulolium may rank equally with timothy …

Comparing Yield And Quality Of Milk From Dairy Cows Fed Stockpiled Annual Ryegrass (Lolium Multiflorum L.) And Cereal Rye (Secale Cereale L.), L. E. Meinhardt, R. L. Kallenbach

IGC Proceedings (1993-2023)

Stockpiling annual ryegrass and cereal rye provides a low cost substitute to hay and creates an excellent source of feed during winter (Kallenbach et al., 2003). In addition to lowering feed costs, grazing increases the conjugated linoleic acid (CLA) content of milk compared to feeding hay. Previous research suggested that forage species might differ in their ability to alter milk CLA content during the growing season (Wu et al., 1997). However, research is needed to determine if different forage species used for winter and early spring grazing impacts the CLA content of milk. The objective of this experiment …

A Grazing Method To Solve The Lack Of Pastures In The Dry Season Of Tropical Areas With Long Periods Of Drought, R. O. Martinez, R. Tuero, M. F. Díaz

IGC Proceedings (1993-2023)

Rotational grazing systems used in tropical areas in Latin America do not solve the great difference in pasture availability between the dry and the rainy season. The main studies on rational grazing (Voisin, 1963) were performed in temperate areas where the deficit of feeds in winter may only be solved with external feeds such as forages and silages produced out of the grazing system. The objective of this work was to demonstrate that it is possible to maintain pasture availability throughout the year with the use of a Pennisetum purpureum clone (Cuba CT-115) adapted to grazing (Martínez et al., …

Breeding And Evaluation Of Forage Soyabeans, T. E. Devine

IGC Proceedings (1993-2023)

The principal use of soyabean in the US in the early 1900s was as livestock forage. Soyabeans are less expensive to establish than small seeded perennial legume forages and can provide legume protein after winter killing of perennial legumes. Soyabean can improve production distribution by vigorous growth during the hot summer season when traditional perennial legumes are less productive.

Effect Of Utilisation Date On The Yield And Quality Of A Semi-Natural Grass Stand In Winter, Jiří Skládanka

IGC Proceedings (1993-2023)

Prolongation of the grazing period into the winter season reduces the costs of feedstuffs for dry cows. To enable the use of pastures in winter it is necessary to carry out the last cut or grazing cycle in June or July and to postpone the last grazing until the first week of August. (Opitz von Boberfeld, 1997). The time of the last utilisation in summer influences the yield and quality of herbage during the winter season (Bartholomew et al., 1997). This research studied changes in yield and quality of a semi-natural grass stand in autumn and in winter following …

Annual Forage Legume Response To Herbicides Labelled For Lucerne Establishment, Twain J. Butler, R. Bow, J. P. Muir

IGC Proceedings (1993-2023)

Weed competition reduces stand establishment, thus lowering forage production and quality. However, there are no herbicides labelled for annual legume establishment, despite several labelled for the establishment of lucerne (Medicago sativa). Some of these may be useful in the establishment and production of annual forage legumes. Lucerne herbicides have greater potential for use on other legumes, since they have grazing and feeding clearance. The objective of this paper is to summarize annual legume yield response trials to herbicides labelled for lucerne establishment.

Hymenachne Amplexicaluis [(Rudge) Nees] Genetic Resources Collection In México, A Suitable Grass For Flood Plains In Tropical Areas, J. F. Enriquez-Quiroz, A. R. Quero-Carrillo, J. Perez-Perez, A. Hernandez-Garay, E. Garcia-Moya

IGC Proceedings (1993-2023)

Hymenachne amplexicaluis [( Rudge ) Nees; 2n= 2x= 24; Azuche, West Indian marsh grass] is a native Central and South America C₃ grass that grows well under intermittent flooding conditions. It produces good seed set and stolons to thrive on new areas assuring its survival, combined with an efficient N metabolism to promote vigorous new growing leaves and tillers (Antel et al., 1998). Azuche is a dual attribute species when introduced to new areas; it has valuable forage attributes but also is a potential weed (Hill, 2000). As Azuche is a native species, one must deal with in …

Critical Analysis Of Tropical Forage Breeding In Brazil, J. A. Usberti Jr., P. B. Alcantara

IGC Proceedings (1993-2023)

Forage grasses account for 90% of the Brazilian forage seed market while the genera Brachiaria, Panicum and others are responsible for 85, 10 and 5% of the traded grass seeds, respectively. Most of the forage grass and legume cultivars available for sowing in Brazil were selected in germplasm banks during the last 20 years, while few of them were derived from artificial crossings, followed by selection for desirable forage traits. The selection of new genetic materials in germplasm banks (exploitation of naturally-occurring genetic variability) is still feasible but the chances of success are decreasing through time. From now on, …

Predictive Modeling Of Cave Entrance Locations: Relationships Between Surface And Subsurface Morphology, William Blitch, Adia R. Sovie, Benjamin Tobin

Faculty, Staff, and Affiliated Publications--KGS

Cave entrances directly connect the surface and subsurface geomorphology in karst landscapes. Understanding the spatial distribution of these features can help identify areas on the landscape that are critical to flow in the karst groundwater system. Sinkholes and springs are major locations of inflow and outflow from the groundwater system, respectively, however not all sinkholes and springs are equally connected to the main conduit system.

Predicting where on the landscape zones of high connectivity exist is a challenge because cave entrances are difficult to detect and imperfectly documented. Wildlife research has a similar issue of understanding the complexities of where …

Differential Behaviour Of Guineagrass (Panicum Maximum Jacq.) Hybrids, With Different Al+3 Reactions, As To Major Nutrient Translocations To The Leaves, R. S. Paterniani, J. A. Usberti Jr., J. C. Werner

IGC Proceedings (1993-2023)

Most of the Brazilian cultivated pasture fields presents soils with high Al⁺³ levels and liming is economically unfeasible. So, there is an urgent need for grasses with good forage yielding potentials that can withstand Al⁺³ deleterious effects (abnormal root development: short, thick and poorly branched roots, which are unable to effectively translocate water and essential nutrients to the leaves) (Foy, 1984); as a consequence, susceptible genetic materials have their field persistences greatly affected, mainly during drought periods. Researches on Al⁺³ reaction are usually compare supposedly resistant/tolerant genotypes with a resistant control check; doing so, the genotypic effect …

Animal Performance And Productivity Of New Ecotypes Of Brachiaria Brizantha In Brazil, Valéria P. B. Euclides, Manuel C. M. Macedo, Cacilda B. Do Valle, R. Flores, M. P. Oliveira

IGC Proceedings (1993-2023)

Brazil has the competitive advantage of a very dynamic and cost effective animal production system on pastures over other countries. The pursuit for more productive forages that will result in higher quality beef at a lower cost is then justified. Brachiaria is the most important forage genus utilised in Brazil, thus an intense search for new cultivars amongst collected and introduced ecotypes from Africa is underway. Following agronomic evaluation of this material in plots, 8 pre-selected Brachiaria ecotypes were tested under intermittent grazing in paddocks (Euclides et al., 2001). Continuing on the process of cultivar development, two out of …

Development Of A Bahiagrass Paspalum Notatum Flugge With Increased Short-Day Biomass, P. Mislevy, Ann R. Blount, T. R. Sinclair

IGC Proceedings (1993-2023)

Low herbage productivity of subtropical grasses during the short-day winter months of October through to March can place a severe burden on livestock producers in Southeastern U.S. Researchers at the University of Florida (Sinclair et al., 2001) hypothesised that the decrease in forage production might result from physiological dormancy induced by short day length. A study using artificial lights to extend the day length demonstrated that maintaining the day length at 15 hr during the short-day length period increased 'Pensacola' bahiagrass P. notatum Flugge saure Parodi forage yield 122% when compared with normal photoperiod (Mislevy et al., 2001). …