Lolium Canariense: An Endemic Ryegrass From Canary Islands,
2024
Investigaciones Agrarias Galicia
Lolium Canariense: An Endemic Ryegrass From Canary Islands, J A. Oliveira, G Charmet, F Balfourier, C Ravel
IGC Proceedings (1977-2023)
The taxonomic position of the endemic Lolium canariense within the genus Lolium has been Investigated by starch gel electrophoresis of 7 isozyme loci. Preliminary results show that L. canariense is preferentially autogamous, with an outcrossing rate of 0.08-0.16. II displays an average gene diversity of intermediate value between that of the strict inbreeder L. persicum and those of the outbreeders L. perenne, L. multiflorum and L. rlgidum. The hierarchical clustering from Nei's genetic distance (Genelics 1978) suggests that L. canariense is clearly differentiated from the group of outbreeding species
The Genera Vicia And Lathyrus In Rio Grande Do Sul (Southern Brazil): Cytogenetic And Isozymic Evaluation As Support For Plant Breeding,
2024
Universidade Federal do Rio Grande do Sul
The Genera Vicia And Lathyrus In Rio Grande Do Sul (Southern Brazil): Cytogenetic And Isozymic Evaluation As Support For Plant Breeding, M T. Schifino-Wittmann, L H. Cardoso De Freitas, A H. Lau
IGC Proceedings (1977-2023)
Native, naturalized and exotic Vicia and l.atliyrus species of Rio Grande do Sul were studied for chromosome numbers and meiotic behaviour, All species were diploid, with essentially regular meiosis and high pollen stainability. Interspecific differences for chiasma frequencies, chromosome and pollen grain size were detected. Polymorphism for chromosome number was observed in Vicia anguslilolia (2n = 10, 12, 14). Bsterase isozyme patterns are being analysed,
Evaluation Of Ecotypes Of Birdsfoot Trefoil (Lotus Cornicultaus L.) And Marsh Birdsfoot Trefoil (Lotus Uliginosus Schk.),
2024
University of Agriculture and Technology, Poland
Evaluation Of Ecotypes Of Birdsfoot Trefoil (Lotus Cornicultaus L.) And Marsh Birdsfoot Trefoil (Lotus Uliginosus Schk.), K Mlynarczyk, L Olesinski
IGC Proceedings (1977-2023)
Ninety-seven ecotypes of birdsfoot trefoil and 75 of marsh birdsfoot trefoil were collected at Olsztyn-Kortowo (north-east Poland). In the years 1987-1991 some morphological and phenological characters of the collected natural populations were examined. The results showed the high differentiation in plant habit, flowering period, thousandseed weight and number of seeds per pod.
Collection Of Native Forage Legume Germplasm In Vietnam,
2024
Universitat, Hohenheim
Collection Of Native Forage Legume Germplasm In Vietnam, Rainer Schultze-Kraft, Ha Dinh Tuan, Nguyen Phung Ha
IGC Proceedings (1977-2023)
A mission to collect germplasm of native legumes with forage potential was carried out In February-March 1992 In Vietnam, The collection route essentially followed a North-to-South transect and covered a wide range of ecological conditions between Hanoi and Ho Chi Minh City. Altogether 195 samples of at least 25 genera weie collected. 639' of the samples corresponded lo species within the high-priority genus Desmodlum, Its related genera Dendrobium, Hegnera, Pliyllodlum and Tadehagl, and the genus Puerarla, The native legume Dora is severely endangered by genetic erosion and areas for urgent future collection missions were ldenlifled.
Growth Characteristics Of Hordeum Bulbosum L. And Its Use As Fodder,
2024
Nigata University
Growth Characteristics Of Hordeum Bulbosum L. And Its Use As Fodder, H Hirota, A Goto
IGC Proceedings (1977-2023)
Pot experiments were conducted to evaluate herbage production and feeding value of Hordeum bulbosum L. during 1988-1990. After spring sowing, tiller and leaf number increased remarkably until the autumn of the seeding year. Three cuttings with 2-month intervals from June gave high production. With autumn sowing, 3-4 cuttings in a growing season assured good regrowth and high production during 2 years after sowing. This grass is of high herbage quality except in heading stage.
Effect Of Management And Cultivar On Nodal Root Development Of White Clover,
2024
AgResearch, NZ
Effect Of Management And Cultivar On Nodal Root Development Of White Clover, J R. Caradus, D F. Chapman, R A. Skipp
IGC Proceedings (1977-2023)
Nodal root development of white clover (Trifolium repens L.) swards was monitored by harvesting marked nodes from late autumn to spring and by taking tiller plugs over 15 months. At a hill country site Grasslands Huia and a large-leaved French eultivar, Crau, had greater nodal root development, in terms of root length, than a smallleaved hill country ecotype. Compadson of the effects of rotational sheep and cattle grazing at both lowland and hill country sites showed greater nodal root development root length and lateral root production under cattle grazing. Percentage of nodes with roots was greater under rotational than set-stocked …
Morphogenetic And Structural Determinants Of Plant Regrowth After Defoliation,
2024
AgResearch, NZ
Morphogenetic And Structural Determinants Of Plant Regrowth After Defoliation, D F. Chapman, G Lemaire
IGC Proceedings (1977-2023)
Responses of forage plants to defoliation can be delineated at two levels: physiological responses and morphological responses. Physiological responses are generally defined as occurring over short time-scales, whereas morphological responses are generally considered as being long-t<;rm. The extent to which physiological and morphological responses influence pasture characteristics and production depends on the defoliation regime, and the balance obtained between the supply and demand of growth resources by plants. Where defoliation is relatively infrequent and lax, plants may maintain balanced growth of root and shoot purely through shortterm physiological responses. However, as defoliation severity increases, morphological adjustments are needed to ensure homeostatic, whole-plant growth. The adaptability of forage species to various points on the continuum of defoliation pressure from lenient to severe depends on their inherent morphological and physiological characteristics. We concentrate on morphogenetic and structural determinants of plant regrowth following defoliation, drawing out the important linkages with the physiological responses. We examine the relationships between plant morphogenesis and sward structure, placing particular emphasis on phcnotypic plasticity as a process whereby plant and population structure can alter to maintain homeostatic growth in response to variation in defoliation management. The imporlnnce of meristem positioning within the sward and of meristem activity, interacting with defoliation management, as determinants of plant production and persistence is discussed. Relationships between plant morphogenesis, herbage growth dynamics and barvestable herbage production are examined and we identify the collection of fundamental physiological and morphological information for a wider array of forage species as an important research goal for improving the productivity and sustainability of the world's grasslands.
Physiology Of Plants Recovering From Defoliation,
2024
University of California, Davis
Physiology Of Plants Recovering From Defoliation, J H. Richards
IGC Proceedings (1977-2023)
Short-term, whole-plant physiological responses of forage plants to defoliation and the characteristics that allow them to rapidly replace lost tissues are the focus of this review. The physiology of defoliationtolerant plants after moderate to severe defoliation has two distinct phases; the first is a transient period of one to a few days and the second is a readjustment of physiological activity and plant morphogenetic Integration that occurs over several weeks. When whole-plant photosynthetic capacity is reduced by substantial defoliation the effects of reduced carbon supply rapidly propagate through a growing plant, affecting shoot growth, root respiration, nutrient uptake and root …
Nitrogen And Phosphorus Nutrition Of Digitaria Eriantha: Is It Limited By Absorption Capacity Or Rate Of Supply?,
2024
University of Witwatersrand
Nitrogen And Phosphorus Nutrition Of Digitaria Eriantha: Is It Limited By Absorption Capacity Or Rate Of Supply?, M C. Scholes, R J. Scholes, J Retief
IGC Proceedings (1977-2023)
Digitaria eriantha was grown from seed collected from low and high nutrient habitats. The plants were grown with either a high or low nutrient supply for 12 weeks. Rates of nitrogen and phosphorus absorption were measured on excised roots using colorimetric assays. The grasses from the low nutrient areas achieved the same maximum uptake rates regardless of the level of N supplied, This was not so for the grasses from the high nutrient site which increased their uptake rates with increased N supply. Plants from the low nutrient site showed markedly increased P absorption when supplied with high levels of …
Effect Of Nitrogen In Fertilizer In Combintation With Potassium And Phosphorus On Rangeland Yield In Cameroon,
2024
Universite de Dschang
Effect Of Nitrogen In Fertilizer In Combintation With Potassium And Phosphorus On Rangeland Yield In Cameroon, E T. Pamo, S Yonkeu
IGC Proceedings (1977-2023)
A study was carried out at Wakwa Animal Research Station on the response of natural pasture to nitrogen fertilization in the presence of P 11osphorus and potassium, and a cutting frequency of 4 weeks. A Cmpletely randomized design with 6 replicates was used. Six fertiliser: 0, SO, 100, 150, 200, 2SO units of N/ha in association with 100 units of P and 100 units K after zero timing was applied after every cutting 0, 10, 20, 30, 40, SO units of Nlba were respectively added to plots which received 0, SO, 100, ISO, 200 and 250 units of Uha. Three …
Vegetation Analysis Of Semi-Arid Regions In North-Eastern Iran,
2024
University of Agricultural Science, Gorgan, Iran
Vegetation Analysis Of Semi-Arid Regions In North-Eastern Iran, M Mesdaghi
IGC Proceedings (1977-2023)
Production of semi-arid rangelands under the 3 conditions of complete protection, moderate and severe grazing were evaluated using double sampling techniques, For production, 1 m2 and for canopy coverage, 25x60 cm quadrats were used, In Gholestan National Park, which was protected for 30 years, the grasses Festuca ovi11a, Agropyro11 tricliopliorum, A. imermedium associated with Medlcago saliva and Onobrycl1is spp. dominated. The dry matter yield in this grassland was about 1500 kg/ha. Under moderate grazing on key areas, the yield declined to 700 kg/ha. The percentage of grasses decreased, liut there were still some grasses even in poor conditions. On the …
Termites Have A Minor Role In The Decomposition Of Senescent Grass Tussocks In A Semi-Arid Woodland In Eastern Australia, J C. Noble
IGC Proceedings (1977-2023)
Decomposition of dead tussocks of 2 grass species (Eragrostis eriopoda and Thyridolepis mitchellima) was studied with and without termites present, both in the absence of large ve.rtebrate herbivores, After 3 years, little tussock residues of either species remained icrespective of treatment, but E. er/opoda decayed much more rapidly than T. mitchellia11a during the first 8 months post mortem (c. 275 cf, 13 kg/ha/month respectively). Thereafter, rate of decay differed little between species. Overall, removal of termites had no significant effect, The data presented in this paper therefore suggest that abiotic processes are dominant influences mediating litter decomposition of …
A Bioeconomic Stocking Rate Model For The Semi-Arid Savanna Of Natal, South Africa,
2024
University of Natal, Pietermaritzburg
A Bioeconomic Stocking Rate Model For The Semi-Arid Savanna Of Natal, South Africa, G P. Hatch, N M. Tainton
IGC Proceedings (1977-2023)
Grazing trials were conducted on 2 sites located In semi-arid savanna of Natal. Three stocking strategies were applied at each site to provide light, intermediate and heavy stocking. Data collected over 5 seasons were used to.develop a bioeconomic stocking rate model. While individual animal performance and nett return per livestock unit (R/LSU) decreased with increased stocking, net return per ha (Riha) increased, Net return was significantly related (P 0, 01) to rainfall and stocking rate, while no significant effect of range condition was detected. Although Increased stocking may be justified In the short• term, this may be associated with both. …
Use Of Water Balance Models To Examine The Role Of Climate In Annual Legume Decline In Southern Australia,
2024
NSW Agriculture
Use Of Water Balance Models To Examine The Role Of Climate In Annual Legume Decline In Southern Australia, M Blumenthal, R Ison
IGC Proceedings (1977-2023)
fhe content of annual medic and subclover (Trifo/ium subterraneum) in rasture Leys has been declining in southern Australia over the last decade. The models GROWEST and ASW were used to simulate available soil water, dry matter yield and seed production of a temperate annual pasture legume using actual climatic data for Forbes in 1987-89. GROWEST was also used to predict DM and seed production and the site and composition of the seed bank for the period 1957-89 for the subclover cultivars Dalkeith and Woogenellup. The period 1979-82 consisted of below average seasons with DM yields restricted to below 3000 kg/ha/year. …
Effects Of Fertilizers And Rest On The Overgrazed Semi-Arid Ranges Of Central Anatolia,
2024
Cumhuriyet (Republik) University
Effects Of Fertilizers And Rest On The Overgrazed Semi-Arid Ranges Of Central Anatolia, U Buyukburc
IGC Proceedings (1977-2023)
To improve the degenerated natural village pastures of Turkey in semi arid regions, different fertilisers and resting treatments were tested. The experiment was established on two rangelands, which showed different plant communities (Thymus squarrosus L. and Artemisia fragrans L.). Each species was dominant in vegetation and had 38-70% weight of total herbage production. At the beginning of the experiment, the dry yield varied from 200 to 565 kg/ha and the average plant cover was 20- 28.5%. Fertilisers, especially 75 or 100 kg/ha of ammonium sulphate, plus superphosphate, or using equal amount of diammonium phosphate DAP (20+20), significantly increased dry yield …
Pasture Composition Influences Soil Erosion In Eucalyptus Woodlands Of Northern Queensland,
2024
QDPI
Pasture Composition Influences Soil Erosion In Eucalyptus Woodlands Of Northern Queensland, J C. Scanlan, J G. Mcivor
IGC Proceedings (1977-2023)
Runoff and soil loss in grazed Eucalyptus woodlands of north Queensland were monitored over a 5-year period. As ground cover increased, runoff and soil loss decreased. When cover exceeded 50%, runoff and erosion were small. Ground cover was a function of standing dry mailer which decreased as tree cover and stocking rate increased and differed between pasture types. Simulated soil losses from these woodlands was <10-2800 kg/ha/year, and runoff was 5- 16 mm/year. Annual soil losses (simulated) were proportional to the square of the annual simulated runoff.
Physiological Response Of White Clover Genotypes To Water Deficit,
2024
AgResearch, NZ
Physiological Response Of White Clover Genotypes To Water Deficit, D J. Barker, J R. Caradus, M T. Mcmanus
IGC Proceedings (1977-2023)
Three plants from each of 2 white clover (Trifolium repens L.) cultivars, Grasslands Kopu and a breeding line selected from germplasm of Syrian origin, were grown in large pots of soil and physiological characteristics measured during a continuous drying phase of 18-37 days. By the end of the experiment, leaf water potential was -2.5 MPa, gravimetric soil water content was 13% (considerably lower than -1.5 MPa), and leaf relative water content was 60%. A 91- fold increase in leaf praline concentration indicated that water stress had altered plant metabolism. Differences in the rate of soil drying occurred between eultivars, but …
Forecasting Annual Drought Conditions For Arid And Semi-Arid Rangelands,
2024
USDA, Agricultural Research Service
Forecasting Annual Drought Conditions For Arid And Semi-Arid Rangelands, C L. Hanson, J R. Wight
IGC Proceedings (1977-2023)
Long-term weather forecasts (>14 days) have improved, but still lack accurate enough information to be valuable; thus, drought forecasts must be based on historical records and calculated probabilities of occurrence. The use of regression techniques to investigate linear dependence between current and preceding years' precipitation or forage yield is illustrated. A 3-state Markov process is used to determine relationships between below-average, average and aboveaverage consecutive annual herbage yields, and winter and spring precipitation amounts. Methods for using natl/ml resource simulation models to forecast ecosystem components such as herbage production, runoff, and erosion with their associated probabilities of occurrence are …
Effects Of An Existing Lucerne Sward On Establishment And Productivity Of Three Over Drilled Grass Species,
2024
Lincoln University
Effects Of An Existing Lucerne Sward On Establishment And Productivity Of Three Over Drilled Grass Species, A Z. Ayalsew, B A. Mckenzie, M L. Smetham
IGC Proceedings (1977-2023)
Effects of contrasting lucerne (Medicago saliva L.) cover (open versus closed canopy) on establishment of overdrilled Bromus wifldeowii Kunth cv. Grasslands Matua prairie grass, Pllalari:r aq11a1ica L. cv. Grasslands Matu phalaris and Loli11m pere111Ie L cv. Grasslands Nui perennial ryegrass were investigated. Prairie grass seedling survival was unaffected by lucerne cover at 84%. However, survival of ryegrass and phalaris was reduced to 35 and 46% of their respective values 'under open canopy. Productivity of all 3 species was affected by canopy state. Leaf area per plant, tiller number per plant and dry matter production were all lower under …
Seasonal Water Use And Productivity Of Lucerne-Grass Pastures,
2024
Lincoln University
Seasonal Water Use And Productivity Of Lucerne-Grass Pastures, B A. Mckensize, R J. Lucas, P Gyamtsho
IGC Proceedings (1977-2023)
A. long-term grazing experiment at Lincoln University examined the yield and water use efficiency (WUE) of pure lucerne (Medicago saliva L.), luceme plus Grasslands Matua prairie grass (Bromus wildenowii Kunth.) and lucerne plus Grasslands Maru phalaris (Phalaris aqualica L.). Pure lucerne, lucerne-phalaris and lucerneprairie yielded 12.7, 11.6 and 10.4 t DM/ha/year. Production from deep soils was 16% greater than from shallow soils. Over a 6 month growth cycle from 29 Sept 88 until 16 May 89 total evapotranspiration did not vary between pasture types and mean water use was 378 mm. Water use was 10% higher on …
