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Articles 2221 - 2250 of 9329
Full-Text Articles in Agricultural Science
Evaluation Of North Carolina Reactive Phosphate Rock As A Phosphorus Fertilizer For Permanent Pastures, A G. Sinclair, P D. Johnstone, L C. Smith, P W. Shannon, M B. O'Connor, L Nguyen, W H. Risk
Evaluation Of North Carolina Reactive Phosphate Rock As A Phosphorus Fertilizer For Permanent Pastures, A G. Sinclair, P D. Johnstone, L C. Smith, P W. Shannon, M B. O'Connor, L Nguyen, W H. Risk
IGC Proceedings (1977-2023)
North Carolina phosphate rock (NCPR) was compared with triple superphosphate (TSP) as a phosphorus (P) fertiliser for permanent grass-clover pastures over a period of 6 years at 12 sites located throughout New Zealand. Pasture production was measured by mowing, and herbage P concentrations were measured on all harvests at 2 sites. In year 1, averaged over all sites, 1 unit of P in NCPR produced the same DM response as 0.24 units of Pin TSP (substitution value=0.24). In year 6 the mean substitution value was 0.80, and over the 6-year period it was 0.60. The site with highest pH (6.3) …
Defining Economically Optimal Phosphorus Fertilizer Rates For Permanent Grass-Clover Pastures In Spain And New Zealand, A G. Sinclair, M Rodriguez Julia
Defining Economically Optimal Phosphorus Fertilizer Rates For Permanent Grass-Clover Pastures In Spain And New Zealand, A G. Sinclair, M Rodriguez Julia
IGC Proceedings (1977-2023)
Economically optimal annual fertiliser phosphorus Prates for maintaining permanent pastures are calculated from a long-term maintenance response curve along with fertiliser price and pasture value. Parameters of the response curve are derived from nutrient balance considerations. The system provides a logical basis for maintenance P fertiliser policies, and results are in accord with limited experimental data.
Salinity Tolerance Of Turf And Forage Grasses, R C. Mckenzie, H G. Najda, J R. King
Salinity Tolerance Of Turf And Forage Grasses, R C. Mckenzie, H G. Najda, J R. King
IGC Proceedings (1977-2023)
There are over 1.2 million ha of cultivated saline land in the province of Alberta, Canada. Our experiment's objectives were to develop reliable recommendations under field conditions of the salinity tolerance of various grasses. Information on how salinity levels influence the growth of grasses under field conditions would provide better management options for forage production. An irrigated site was established at Brooks and a dryland site at Hanna, Alberta. Twenty-five species are being evaluated under irrigation and I 9 under dry land using a randomised block design, Forage yields indicate that tall wheatgrass (Elytrigia pontica), Dahurian wildrye (Elymus …
Dynamics And Interactions Of Carbon, Nitrogen, Phosphorus And Sulphur Cycling In Grazed Pasture, A K. Metherell, C V. Cole, W J. Parton
Dynamics And Interactions Of Carbon, Nitrogen, Phosphorus And Sulphur Cycling In Grazed Pasture, A K. Metherell, C V. Cole, W J. Parton
IGC Proceedings (1977-2023)
There are close links between the carbon (C), nitrogen (N), phosphorus {P) and sulphur (S) cycles. This is especially evident in legume-based pasture in which ahe application of P and S fertilisers are required to achieve saaisfactory levels of N2 fixation and pasture production The dynamics of the nutrient cycles are controlled largely by the rates of pasture production and consumption, and by the rate of decomposition of organic matter. The CENTURY soil organic matter model integrates climate, soil and management driving variables to predict C, N, P and S dynamics. Simulated effecls of P and S fertiliser on nutrient …
A Feed Production System Utilizing Steep Grasslands And Eutrophic Hydro-Environments In Japan, K Kabata, C Okamoto, P Lowilai, M Kikuchi
A Feed Production System Utilizing Steep Grasslands And Eutrophic Hydro-Environments In Japan, K Kabata, C Okamoto, P Lowilai, M Kikuchi
IGC Proceedings (1977-2023)
One important landscape feature of Japanese grassland is the presence of much steep hill country. Precipitation is high in these areas. Soil nutrients are washed away into hydro-environments such as rivers, lakes and oceans. Waler pollution, especially eutrophication, has become a serious world-wide problem in recent years. In the feed production system of steep grasslands, it is suggested that a mixed pasture system is useful in promoting annual plant production in steep mountainous lands of the Aso area of Japan. Furthermore, the cultivation of water hyacinth (Eichhomia crassipes) in eutrophicated waters, in order lo remove the nutrient elements …
Recent Considerations Of Grassland "Soil Quality" In Temperate Regions, S P. Mcgrath, S C. Jarvis
Recent Considerations Of Grassland "Soil Quality" In Temperate Regions, S P. Mcgrath, S C. Jarvis
IGC Proceedings (1977-2023)
The term "soil quality" is increasingly being used in Europe, albeit in an ill-defined way. Perceived quality depends critically on the use being made of the soil and the tolerance of other parts of the environment to substances moving from soils. This paper focuses on issues relevant to the maintenance of quality in temperate grassland soils. Soils are under threat from heavy metals, organic contaminants and radionuclides because they are sinks for many of these substances, thus lending to accumulation. The impact of these contaminants is assessed, along with the management options and relevant legislation to minimise their effects. Most …
Soil Characteristics And Elemental Cycling In Temperature Grasslands: Are Landscape Dynamics Controlled By Microsite Conditions?, W B. Mcgill, R A. Brijber, R A. Janzen, J F. Dormaar, R.J K. Myers
Soil Characteristics And Elemental Cycling In Temperature Grasslands: Are Landscape Dynamics Controlled By Microsite Conditions?, W B. Mcgill, R A. Brijber, R A. Janzen, J F. Dormaar, R.J K. Myers
IGC Proceedings (1977-2023)
Temperate grasslands are treated as dynamic systems, and are examined here with regard to processes and mechanisms controlling their dynamics. Recent literature dealing with grassland nutrient cycling as driven by interactions among soil organisms, regulated by soil architecture, and augmented by management is examined and evaluated. Emphasis is given to root-soil interactions, including those involving mycorrhizal associations. The challenge is also presented to move beyond the biomass, to discern activities and dynamics of individual soil microbial populations and changes in soil communities as indicators of soil quality and stress on grassland soil-plant systems. Decomposition is fundamental lo nutrient dynamics. From …
Carcinogenicity Of Bracken Fern (Pteridium Spp.) In Relationship To Grazing Ruminants, B L. Smith, D R. Lauren, P P. Embling, M Agnew
Carcinogenicity Of Bracken Fern (Pteridium Spp.) In Relationship To Grazing Ruminants, B L. Smith, D R. Lauren, P P. Embling, M Agnew
IGC Proceedings (1977-2023)
Bracken fern (Pteridium spp.) is the only higher plant which has been shown to cause cancer naturally in animals. Bracken contains ptaquiloside (Pta) a known clastogen and mutagen which is believed to be the major carcinogen involved in the urinary bladder neoplasia. In New Zealand, bracken fern from an area where bovine enzootic haematuria occurs has been shown to have much higher concentrations of Pia than an area where the disease has not been identified. The difference was shown to be related to the bracken rather than the environment and was widespread for the plants in the two areas …
Biological Control Of A Toxigenic Pithomyces Chartarum Strain With A P. Chartarum Strain That Does Not Produce Sporidesmin, R G. Collin, N R. Towers
Biological Control Of A Toxigenic Pithomyces Chartarum Strain With A P. Chartarum Strain That Does Not Produce Sporidesmin, R G. Collin, N R. Towers
IGC Proceedings (1977-2023)
Pitlromyces clrartamm strain WLI0, a high-sporing sporidesminproducing strain isolated in New Zealand, was grown in co-culture with Pillwmyces chartarttm 306, a high-sporing non-sporidesminproducing strain isolated in South Africa, Growth on rabbit pellet agar plates demonstrated that competition occurred between the two strains and resulted in a significant decrease in total sporidesmin levels. This result shows that biological control of toxigenic Pithomyces is possible under laboratory conditions and raises the potential for similar control to occur under field conditions.
Effects Of Cultivar And Stage Of Growth Of Legumes On The Rate Of Digestion In Cow Rumen And Relative Potential For Reducing Bloat, S F. Ledgard, V R. Carruthers, B E. Marris, G J. Brier
Effects Of Cultivar And Stage Of Growth Of Legumes On The Rate Of Digestion In Cow Rumen And Relative Potential For Reducing Bloat, S F. Ledgard, V R. Carruthers, B E. Marris, G J. Brier
IGC Proceedings (1977-2023)
The disappearance of dry matter from herbage incubated in nylon bags in the rumen of fistulated dairy cows over 4 h (initial rate of digestion, IRD) was measured in order to assess the relative bloat potential of several legume species and cultivars. The IRD was least for the nonbloating Lotus pedunculatus and highest for Trifolium pratense and Medicago saliva, species known to cause bloat. The IRD of Trifolium repens cultivars was highest for Sabeda and least for Blanca, 6 other cultivars being intermediate and similar. These differences in IRD between cultivars indicates variation in bloat potential and the possibility of …
A Slow Release Intra-Ruminal Device For Protection Against Facial Eczema In Sheep, R Munday, E A. Fowke, A M. Thompson, C Wesselink, N R. Towers
A Slow Release Intra-Ruminal Device For Protection Against Facial Eczema In Sheep, R Munday, E A. Fowke, A M. Thompson, C Wesselink, N R. Towers
IGC Proceedings (1977-2023)
Facial eczema (FE) is a hepatogenous photosensitization disease of ruminants which causes severe losses in agricultural revenue in New Zealand. It is caused by sprophytic, a myotoxin produced by the saprophytic pastoral fungus Pilllomyces chartarum. Zinc (Zn) salts, given to animals before exposure to the toxin, protect against the harmful effects of sporidesmin. Large amounts of Zn are required and dosing must be continued, at regular intervals, throughout the period when animals are exposed to the fungus. While practicable for dairy cattle, these requirements preclude the routine use of Zn for FB prophylaxis in sheep. For these animals, a …
Effects Of Growth Stage And Grain Glucosinolates Content On Rapeseed Forage Feeding Value, Marc Ghesquiere, J C. Emile, R Traineau, R Giovanni, M Renard
Effects Of Growth Stage And Grain Glucosinolates Content On Rapeseed Forage Feeding Value, Marc Ghesquiere, J C. Emile, R Traineau, R Giovanni, M Renard
IGC Proceedings (1977-2023)
Castrated sheep on maintenance were fed in 2 consecutive years for 4 weeks with fresh summer-sowri rape (Brassica napus) forage. In spite of the energetic value at flowering stage (both by ill vitro or in vivo method) being lower than at the vegetative stage, it appeared to be quite good in comparison with the energetic value of grasses or legumes at flowering stage. We did not observe any difference linked with seed glucosinolates content.
Studies On Disappearance Of Nitrate In Forage Crops During Ensilage, T Masuko
Studies On Disappearance Of Nitrate In Forage Crops During Ensilage, T Masuko
IGC Proceedings (1977-2023)
Italian ryegrass (Lolium multiflorum Lam.) containing large amounts of nitrate was ensiled in the laboratory silo in 5 experiments. Variations in (1) Exp l; additives (CaCO3, glucose and urea), (2) Exp 2; heavy or light consolidation, (3) Exp 3; length of chop (10 or 50 mm), (4) Exp 4; moisture level of material (86.9, 77. land 51.5%) and (5)Exp5; ensilage temperature (15, 28 and 35°C), were investigated. In Exp I, the silages with CaCO3 + glucose and glucose alone added at ensiling were good quality and the rate of nitrate disappearance wns 40.7% and 22.6% respectively. In Exp 2, …
Acremonium Coenophialum And Cultivar Effects On Tall Fescue Seedling Vigour And Stand Establishment, M Collins, D M. Tekorny, J C. Henning
Acremonium Coenophialum And Cultivar Effects On Tall Fescue Seedling Vigour And Stand Establishment, M Collins, D M. Tekorny, J C. Henning
IGC Proceedings (1977-2023)
The fungal endophyte (Acremonium coenophialum Morgan-Jones and Garn) imparts tolerance to stresses, such as drought, to tall fescue (Festuca arundinacea Schreb.). We conducted 3 field trials to study endophyte, seed vigour and cultivar effects on tall fescue emergence. Seven seedlots of Kentucky 31 (KY31) and 5 seedlots of Johnstone with acceptable germination, but variable vigour, were seeded at 17, 22 and 28 kg/ha at 3 dates. Increased seeding rate consistently increased seedling number. Johnstone seedlots were endophyte-free, while 5 of the 7 KY3 l seedlots were infected. Low-vigour Johnstone had fewer seedlings than low-vigour KY3 I; however, there was …
Effect Of Tiller Endophyte Infection Frequency And Nitrogen Fertilizer Rate Of Tall Fescue On Steer Performance Over Nine Seasons Of Grazing, J A. Stuedemann, S R. Wilkinson, D P. Belesky, F N. Thompson, D L. Breedlove, D M. Hildreth, H Ciordia, A H. Parks, C S. Hoveland, J Huang
Effect Of Tiller Endophyte Infection Frequency And Nitrogen Fertilizer Rate Of Tall Fescue On Steer Performance Over Nine Seasons Of Grazing, J A. Stuedemann, S R. Wilkinson, D P. Belesky, F N. Thompson, D L. Breedlove, D M. Hildreth, H Ciordia, A H. Parks, C S. Hoveland, J Huang
IGC Proceedings (1977-2023)
Acremonium coenopliialium-infected tall fescue (Festuca arrundinacea Schreb.) is associated with animal health problems including reduced ,veight gains. Twelve 0.7 ha paddocks were used to study Kentucky- 31 tall fescue at low (LE=25%) or high (HE::58%) tiller endophyte (E) infection frequencies and fertilised with either 134 (LN) or 336, kg nitrogen/ha/year (HN) in a 22 factorial arrangement of treatments. Yearling Angus steers grazed under put-and-take management from April or May through late July or early August in each of nine years. In all except one year, ADG was lower (P<0.0769 to P<0.0018) on HE than LE. In 4 of 9 years, HN lowered (P<0.0821 to P<0.0003) ADG compared to LN. In only 2 of 9 years was there an NxE interaction (P<0,0537), the interactions expressing opposite effects when comparing the 2 years. In all but 3 years there was a linear (P<0.0606 to P<0.0019) relationship between endophyte infection rate and ADG. In only 1 of 9 years were quadratic effects significant (P<0.0407). Endophyte infestation consistently lowered steer AOG in a linear fashion with N effects less distinct,
Variation In The Isoflavone And Pterocarpan Contents Of Red Clover, T Mela, J Laakso, T Maenpaa, H Ihamaki
Variation In The Isoflavone And Pterocarpan Contents Of Red Clover, T Mela, J Laakso, T Maenpaa, H Ihamaki
IGC Proceedings (1977-2023)
Variations in isoflavone and pterocarpan contents were studied in cloned material of red clover (Trifolium pratense L,), The most abundant constituents in the leaves, as determined by gas chromatography, were formononetin (50%) and biochanin A (25%), whereas the rools were characterised by the pterocarpan manckiain (45%). The amounts of leaf isoflavones (range 100-880 µg/100 mg DM) differed significantly between clones at subsequent growth stages, and considerably lower levels were found when compared with the control material. The contents were highest in the beginning of the growing season (June), but decreased strongly towards the end of the lowering period. The …
Variability Of Oestrogen Content In Large Collections Of Subterranean Clover And Its Implications For Selection, Efisio Piano, A Tava, F Spanu, L Pecetti
Variability Of Oestrogen Content In Large Collections Of Subterranean Clover And Its Implications For Selection, Efisio Piano, A Tava, F Spanu, L Pecetti
IGC Proceedings (1977-2023)
Large collections of subterranean clover lines were evaluated for the content of oestrogenic isoflavones formononetin, genistcin and biochanin A. Differences among the species Trifolium brachyalycinum, T. subterraneum and T. yanninuicum were determined mostly by differences in the content of individual isoflavone components rather than in total isoflavone content. The concentration of the most biologically active isoflavone formononetin was highest in T. yaminicum and lowest in T. brachycalycinum. There was extreme variation among lines for isoflavone contents. The variance among populations (means of lines from the same collection site) wns significant in all species, suggesting some influence of the environment …
Integration Of High Formononetin Red Clover In Sheep Grazing Systems, G S. Baxter, D R. Stevens, A J. Harris
Integration Of High Formononetin Red Clover In Sheep Grazing Systems, G S. Baxter, D R. Stevens, A J. Harris
IGC Proceedings (1977-2023)
Pasture and animal production from pastures based on perennial ryegrass (Lolium perenne L.) with either white clover (Trifolium repens L.), red clover (Trifolium pratense L.), or a dual clover base having 60% of the area in white clover and 40% in red clover, were compared over 3 years in self-contained I ha farmlets stocked with 20 ewes/ha, Annual pasture production was similar on all three farmlets, although autumn production of the red clover farmlet was significantly lower than the white or mixed clover systems. Legume production was greatest on the mixed and red clover farmlets in summer and the …
Drought Pearl Millet- An Unpalatable Enigma, D J. Minson, J B. Hacker, M Shimojo, P Stuart, J Slatter
Drought Pearl Millet- An Unpalatable Enigma, D J. Minson, J B. Hacker, M Shimojo, P Stuart, J Slatter
IGC Proceedings (1977-2023)
After planting in late 1989 there were many reports that Nutrifeed was unpalatable to cattle, sheep and horses. Seventyfive properties were visited where unpalatability was common, a questionnaire was distributed and samples of forage and soil were analysed. Forty-six properties reported unpalatability but on the other 29, pearl millet was palatable. Unpalatability developed only when forage grown on soil high in available nitrogen was subjected to a shortage of water. Unpalatable forage was dark green, contained more than 3S g N/kg DM and was often low in phosphorus, After rain or irrigation the new growth was usually palatable but stock …
Accumulation Of Pyrrolizidine Alkaloids During Growth Of Tall Fescue, Lowell Bush, Scott Gay, Walyati Burhan
Accumulation Of Pyrrolizidine Alkaloids During Growth Of Tall Fescue, Lowell Bush, Scott Gay, Walyati Burhan
IGC Proceedings (1977-2023)
The experiments were initiated to determine the association between growth of the fungal endophyte Acremoium coenophliaum and the accumulation of pyrrolizidine alkaloids (PA) and to measure the influence of A. coenophialum on water use and photosynthesis by tall fescue (Festuca arundinacea Schreb.). PA concentration increased with growth after seeding. First and second regrowth tissues contained higher levels of PA than first harvest tissue of the same age. Endophyte content in the pseudostems increased until 11 weeks after seeding and then decreased. Pseudostems of each subsequent regrowth period contained less endophyte. During a soil drying cycle 'l'w was …
Steer Performance From Tall Fescue Pastures With Three Levels Of Acremonium Coenophialum Infestation, J C. Waller, H A. Fribourg, R W. Thompson, A B. Chestnut
Steer Performance From Tall Fescue Pastures With Three Levels Of Acremonium Coenophialum Infestation, J C. Waller, H A. Fribourg, R W. Thompson, A B. Chestnut
IGC Proceedings (1977-2023)
Two replications of 1.2-ha pastures were seeded in 20-cm drill rows to 3 treatments: endophyte-free (E-) tall fescue (Festuca arundinacea); tall fescue infested at 80% (E+) with Acremonium cenophialum; a mixed sward of alternate sets of 4 drill rows of E+ and E- tall fescue (E+/E-). Stand density and endophyte levels were monitored every 6 months, remaining at original levels throughout the study. Each pasture had 3 test steers (Bos taurus) with extra steers used as needed to maintain forage height 2.5-7.5 cm. Average daily gain (ADG) ranged from about 300 to over 700 g/day …
Coping With Mycotoxins That Constrain Animal Production, N R. Towers, M R. Siegel
Coping With Mycotoxins That Constrain Animal Production, N R. Towers, M R. Siegel
IGC Proceedings (1977-2023)
Many fungi are parasites and saprophytes of growing and conserved forage crops. A number of these produce mycoloxins, the synthesis of which is controlled by the interaction of fungal and host genomes and the environment. Mycotoxins have diverse chemical structures and elicit a range of responses in ruminant animals. Some of the more important mycotoxin-producing fungi found in forages include Claviceps spp. (ergot alkaloids, paspalitrems) and Acremonium spp. (ergot alkaloids, lolitrcms) causing various forms of ergot toxicity and neurological (lremorgenic) disorders; Pithomyces clrartarum (sporidesmin) and other fungal species causing photosensitisation (e.g., facial eczema, geeldikkop); Phomopsis /eptoslromiformis (phomopsins) causing lupinosis; Rhizoctonia …
Recent Developments In Higher Plant Toxin Research Of Relevance To Animal Production, A A. Seawright, M P. Hegarty
Recent Developments In Higher Plant Toxin Research Of Relevance To Animal Production, A A. Seawright, M P. Hegarty
IGC Proceedings (1977-2023)
Advances have been achieved in the diagnosis of chronic intoxications caused by poisonous plants in which the pathological changes present In the affected animals are not definitive, by the chemical identification of toxin adducts in their tissues. This has been demonstrated for pyrrolizidine alkaloids which are of global significance as plant poisons and has resulted on occasion in more determined efforts in eliminating the plants responsible. Many plant toxins need to be metabolised for toxicity within the animal's tissues in order to result in disease, and the furanoterpenes found mainly in myoporaceous plants are e,rnmples, Dietary regimes that lend lo …
Invertebrate Pests, Plant Pathogens And Beneficial Organisms Of Improved Temperate Pastures, R P. Pottinger, M J. Barbeiti, T J. Ridsdill-Smith
Invertebrate Pests, Plant Pathogens And Beneficial Organisms Of Improved Temperate Pastures, R P. Pottinger, M J. Barbeiti, T J. Ridsdill-Smith
IGC Proceedings (1977-2023)
The role of pests, pathogens and beneficial organisms in temperate pasture and animal production is highlighted. Significant differences between pests and. the severity of their infestations exists between the Northern and Southern Hemispheres, because both pasture and pest species and their natural enemies have been carried by colonists to the New World countries in the Southern Hemisphere, Pests and pathogens place significant constraints on the sustainability and productivity of pastoral agriculture. Acquisition of basic databases and development of a wider range of controls has occurred over the past 25 years, but the effort has been disjointed. Knowledge of the more …
Invertebrate Pests, Plant Pathogens, And Beneficial Organisms In Extensive Natural Grassland, J G. Watts, L W. Burgess, E W. Huddleston
Invertebrate Pests, Plant Pathogens, And Beneficial Organisms In Extensive Natural Grassland, J G. Watts, L W. Burgess, E W. Huddleston
IGC Proceedings (1977-2023)
After many decades of research on their control, insects and weeds still arc a major factor in semi-arid grassland ranching. Much has been learned concerning their biology, habits and chemical control but penetrating study of the microbial world surrounding them is quite recent. Plant pathogens are credited with little damage to semiarid grasslands. Potentially, their most important role may be one of toxigensis among grazing animals after unusual weather that promotes exceptional increase of any one or a combination of several indigenous toxigenic fungi on senescing grasses. Objective cost-benefit consideration of pest and disease control was limited in past decades …
Resistance Versus Susceptibility To Verticillium Albo-Atrum In Alfalfa, B W. Pennypacker, K T. Leath, D P. Knievel, E J. Pell
Resistance Versus Susceptibility To Verticillium Albo-Atrum In Alfalfa, B W. Pennypacker, K T. Leath, D P. Knievel, E J. Pell
IGC Proceedings (1977-2023)
Alfalfn (Medicago saliva L.) clones, susceptible and resistant to Verticillium albo-atrum (Van), were systematically infected with Vaa via stubble inoculation with conidial suspensions. Progress of infection and anatomical host responses was monitored by sequential sampling, sectioning, staining and examination with light microscopy. Effect of infection on photosynthesis was assessed in vivo by measuring net photosynthesis and activity of ribulose 1, 5-biphosphate carboxylaseoxygenase (rubisco) via a CO2 drawdown curve. hr vitro activity of rubisco was determined by protein extraction and uptake of radioactive CO2. Susceptible and resistant clones exhibited leaflet chlorosis and abscission. Also, the pathogen produced spores that germinated …
Breeding For Multiple Pest Resistance As A Strategy To Improve White Clover Persistence, G A. Pederson, G L. Windham, M R. Mclaughlin, R G. Pratt, G E. Brink
Breeding For Multiple Pest Resistance As A Strategy To Improve White Clover Persistence, G A. Pederson, G L. Windham, M R. Mclaughlin, R G. Pratt, G E. Brink
IGC Proceedings (1977-2023)
White clover (Trifolium repens L.) cultivars grown in the USA are susceptible to many pathogens, pests and environmental stresses which have been shown to affect persistence adversely. The strategy used in our breeding programme is to first develop white clover populations resistant to individual pathogens and pests, and then incorporate this resistance into multiple-pest-resistant populations. Germplasms with resistance to peanut stunt virus (PSV), alfalfa mosaic virus (AMY), and clover yellow vein virus (CYVV), and with drought tolerance have been released. From these germplasms and other source materials, we have developed additional populations with resistance to southern root-knot nematode ( …
Clover Cyst Nematode Resistance In White Clover, J Van Bosch, C F. Mercer, J L. Grant, I K. Black
Clover Cyst Nematode Resistance In White Clover, J Van Bosch, C F. Mercer, J L. Grant, I K. Black
IGC Proceedings (1977-2023)
White clover (Trifolium repens L.), a key legume in New Zealand pastures, is parasitised by Heterodera trifolii, the clover cyst nematode. Resistance breeding is the most feasible control, and screening of 1st generation crosses has made considerable progress. Progeny of parents selected for resistance had only 39% cysts/g root dry weight of susceptible lines, and all resistant lines were lower when ranked. These resistant selections also had less fewer cysts per plant, heavier root dry weights and higher shoot growth scores. The parents of the most resistant lines were from two Italian ladino cultivars (Ladino Gigante Lodigiano and …
Rhoma Black Stem Disease- A Threat To Susceptible Annual Medic Pastures, M J. Barbetti
Rhoma Black Stem Disease- A Threat To Susceptible Annual Medic Pastures, M J. Barbetti
IGC Proceedings (1977-2023)
Phoma black stem disease, caused by Phoma medicaginis, is the most important fungal disease of annual Medicago spp. (medic) pastures in Western Australia. It is readily seed-borne and this provides an important inoculum source for spreading the disease into new sowings in areas free of leguminous crop residues. The disease produces dark brown to black lesions on cotyledons, leaves, petioles and stems and can cause leaf drop and petiole and stem collapse, Reductions in herbage production of up to 169!, and seed yield of up to 209!, have been recorded in grazed swards, while in ungrued swards, losses in herbage …
Effectiveness Of Acremoniu Lolli In Annual Ryegrass In Controlling Greenbug (Schizaphis Graminum Rondani) Injury, L R. Nelson, Marta R. Harrington, D Marshall
Effectiveness Of Acremoniu Lolli In Annual Ryegrass In Controlling Greenbug (Schizaphis Graminum Rondani) Injury, L R. Nelson, Marta R. Harrington, D Marshall
IGC Proceedings (1977-2023)
This experiment tested 3 ryegrass (Lolium multiflorum Lam.) genotypes with (E+ )° and without (E-) endophyte, to determine the effectiveness of the endophyte in reducing leaf damage caused by greenbugs (Schlzaplris granthum Rondani). Results Indicated that presence of endophyte increased resistance in only I of 3 lines tested. The apparent resistance was observed.as leaf necrosis (leaf necking, yellowing, tip die-back, and leaf death). Resistance was not observed until green bug reinfestation of 3-month-old plants. A control with E+ Kentucky 31 fescue (Festuca arundinacea Schreb.) also had reduced greenbug damage compared with E- Kentucky 31 plants. This study …