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Articles 61 - 90 of 10623
Full-Text Articles in Plant Sciences
Intraspecific Variation For Salt Tolerance In White Clover, M E. Rodgers, C L. Noble, M E. Nicolas, G M. Halloran
Intraspecific Variation For Salt Tolerance In White Clover, M E. Rodgers, C L. Noble, M E. Nicolas, G M. Halloran
IGC Proceedings (1993-2023)
Variation in the salt tolerance of 10 commercial cultivars of white clover (Trifolium repens L.) was evaluated in greenhouse and field· experiments over a range of NaCl concentrations. Cultivars differed significantly in terms of yield, shoot ion concentrations and parameters of growth such as leaf expansion and petiole elongation rates but not in the root concentrations of Cl or Na. The ability to control the entry and distribution of Cl and Na into the shoot (demonstrated by tolerant cultivars Haifa and irrigation compared with sensitive cultivars Ladino and Tamar) was related to the salt tolerance rankings observed in both …
Breeding For Tolerance To Toxic Levels Of Aluminum In Alfalfa, T A. Campbell, Z L. Xia, P R. Jackson, C D. Foy, G R. Bauchan
Breeding For Tolerance To Toxic Levels Of Aluminum In Alfalfa, T A. Campbell, Z L. Xia, P R. Jackson, C D. Foy, G R. Bauchan
IGC Proceedings (1993-2023)
An estimated 40% of all arable soils are acidic, and aluminum (Al) toxicity is often the primary plant-growth-limiting factor in these soils. Bxcess exchangeable Al is especially harmful in subsoils because it reduces rooting depth and branching and predisposes plants,to injury by drought. Our research to date indicates that there is substantial genetic variation in alfalfa (Medicago sativa L.) in response to toxic levels of Al, but that phenotypic recurrent selection appears to have been only marginally effective in selecting for Al tolerance. Possible alternative breeding approaches would entail re-evaluating selections to help obviate the effects of genotype x environment …
Evaluating Livestock Selling Strategies Based On Forage Availability, Lucas D. Parsch, W M. Watts, O J. Loewer, P L. Luster
Evaluating Livestock Selling Strategies Based On Forage Availability, Lucas D. Parsch, W M. Watts, O J. Loewer, P L. Luster
IGC Proceedings (1993-2023)
The ORAZB simulation model was used to evaluate 4 alternative decision rules to trigger the removal of stocker steers from pasture in order to avoid risk when pasture conditions are suboptimal, Each of the four decision rules was simulated for 8 stocking rates over a 13- year period, Results of the analysis indicated that decision rules which trigger livestock removal based on minimum herbage availability result in shorter grazing periods and higher average daily gain compared with decision rules which trigger removal based on livestock weight loss. Although decision rules based on minimum herbage availability thresholds resulted in the highest …
Grazing System And Grazing Pressure Effects On Herbage And Lamb Production From Subclover Interseeded Annual Grassland, Thomas C. Griggs, Milton B. Jones, Montague W. Demment
Grazing System And Grazing Pressure Effects On Herbage And Lamb Production From Subclover Interseeded Annual Grassland, Thomas C. Griggs, Milton B. Jones, Montague W. Demment
IGC Proceedings (1993-2023)
Information on management effects on the productivity of improved mediterranean annual grassland pastures in California is limited, Our objectives were to compare herbage and lamb production in subclover (Trlfolium subterraneum L.)-seeded annual grassland under different intensities of continuous and rotational systems of grazing. Grazing systems at 3 grazing pressures were applied in a factorial arrangement to 12 0.6S-ha pastures in a randomised complete block design replicated twice. Targhee lambs grazed pastures from 28 February to 9 May in 1989 and from S March to 1 May in 1990. Lambs occupied each of the eight paddocks in rotations for 1-4 …
Intensive Grazing Of High Producing Holstein Cows: Milk Production, Forage Utilization And Profit Potential At Three Stocking Rates, S L. Fales, L D. Muller, M O'Sullivan, L E. Lanyon, R J. Hoover, L A. Holden
Intensive Grazing Of High Producing Holstein Cows: Milk Production, Forage Utilization And Profit Potential At Three Stocking Rates, S L. Fales, L D. Muller, M O'Sullivan, L E. Lanyon, R J. Hoover, L A. Holden
IGC Proceedings (1993-2023)
A farmlet study was conducted to investigate lhe potential for improving dairy productivity and profit potential through increasing stocking rates above those commonly used in 1he north-eastern USA. High-producing Holstein cows were grazed at seasonal stocking rotes (SR) of 3.9 (HSR), 3.2 (MSR) and 2.5 (LSR) cows/ha. Measurements were taken of quantity and quality of pasture offered to cows, silage harvested and fed and milk production during 175 days of grazing in 1990. Results showed a direct relationship between stocking rote and pasture quality and a negative relationship with the percentage of the pasture rejected by cows. Milk production (mean, …
Intensive Grazing Systems And Methods For Beef Cattle, V G. Allen, J P. Fontenot, M A. Cochran, A Brock, W Mcclure, J Wilkins
Intensive Grazing Systems And Methods For Beef Cattle, V G. Allen, J P. Fontenot, M A. Cochran, A Brock, W Mcclure, J Wilkins
IGC Proceedings (1993-2023)
Three experiments were conducted to determine effects of grazing systems and methods on beef production. In experiment 1, cows, calves and stockers grazed tall fescue-clover (Festuca arundinacea-Trifolium repens) in a l 6-paddock system using rotational stocking or a 3-paddock system using continuous stocking as grazing methods. In experiment 2, stocker steers grazed orchardgrass-clover (Dactylis glomerata-Trifolium pratense) using buffer grazing with continuous stocking or a 14-paddock rotational stocking method. In experiment 3, 4 grazing systems were compared using sequence grazing combinations of cool-and warmseasoo perennial and annual forages. In experiments l and 2, there were no differences in …
Selection Pattern Of Holstein-Zebu Cows Grazing Stoloniferous And Tufted Type Tropical Grasses In A Cafeteria Type Trial, Francise E. Davis
Selection Pattern Of Holstein-Zebu Cows Grazing Stoloniferous And Tufted Type Tropical Grasses In A Cafeteria Type Trial, Francise E. Davis
IGC Proceedings (1993-2023)
Seven stoloniferous and 7 tufted grasses are being evaluated in a longterm trial on an acid ultisol in Trinidad in duplicate 3x3 m plots. The grasses were cut at five weekly intervals and nitrogen at 40 kg/ha applied after every harvest. A basal dressing of 125 kg P20, and 100 kg '½O and a trace element mix was applied twice annually. After culling in May 4 milking cows were allowed to graze the area. There was no significant difference in dry matter yield between the stoloniferous and tufted grasses, but there were significant differences within each type of grass in …
Effect Of Percentages Calluna Vulgaris Cover And Cow And Ewe Physiological Status On Animal Production On Mountain Pastures, K Osoro, R Celaya, Mamen Olivan
Effect Of Percentages Calluna Vulgaris Cover And Cow And Ewe Physiological Status On Animal Production On Mountain Pastures, K Osoro, R Celaya, Mamen Olivan
IGC Proceedings (1993-2023)
The effect percentage cover of Calluna vulgaris (30 or 70%) on performance of dry and lactating ewes and cows with their lambs and calves was studied during 1990 and 1991. Lactating cows had greater body weight losses than dry ones, the difference being 0.3 and 0.S kg/day for 1990 and 1991 respectively. Percentage C.vulgaris cover (30 or 70%) caused differences in body-weight losses· similar to those caused by physiological status. Milk production from the cows, and therefore calf live-weight gain, were significantly higher in the group grazing on the plot with 30% Calluna (0.62 and 0.71 kg/day for 1990 …
Adaptation Of Some Grass Species To Grazing, Marc Ghesquiere, J C. Emile, X Charrier, R Traineau
Adaptation Of Some Grass Species To Grazing, Marc Ghesquiere, J C. Emile, X Charrier, R Traineau
IGC Proceedings (1993-2023)
To examine the grazing behaviour of some grass species, 2 linked trials were set up in Lusignan (France), Dry matter yields of 10 species were recorded by frequent mechanical cuts (every 15 days) and compared with the ability to feed sheep under continuous grazing management. The dry matter yield of the genotypes ranged from 5600 to 8600 kg DM/ha and the grazing yield from 86 to 183 days x animal. The well-known species, such as Bromus siIchensis L., 8. caIhar1ic11s L. and Dactylis glomerata L. usually used in farms allowed high dry matter and grazing yields, but some secondary species …
Quantification Of Nutrients Consumed And Utilized By Holstein Cows Grazing Grass Pastures In The North-Eastern Usa, Lisa A. Holden, L D. Muller, G A. Varga, S L. Fales
Quantification Of Nutrients Consumed And Utilized By Holstein Cows Grazing Grass Pastures In The North-Eastern Usa, Lisa A. Holden, L D. Muller, G A. Varga, S L. Fales
IGC Proceedings (1993-2023)
Managing the nutrition of high producing dairy cows on pasture in the north-eastern USA is challenging owing to difficulty in accurately estimating intake and In determining nutrient utilisation by grazing dairy cows. In Trial 1, 16 lactating Holstein cows were used to estimate intake with an intensively grazed orchardgrass (Dactylis glomerata L.) pasture with 2 stocking rates of 2.S and 3,9 cows/ha in a 24 week grazing season. Cows were fed a grain supplement which comprised about 35% of the diet dry matter. Chromium oxide was used as an external marker in faeces, Results of Trial 1 indicated total …
Crop Processing And Fractionation As A Commercial Proposition To Forage-Based Animal Systems, H T. Ostrowski-Meissner
Crop Processing And Fractionation As A Commercial Proposition To Forage-Based Animal Systems, H T. Ostrowski-Meissner
IGC Proceedings (1993-2023)
The paper outlines crop processing and fractionation technology as it applies to an intensive forage-based operation with beef cattle, The benefits of forage processing prior to its feeding to cattle are described with an emphasis not only on the uniformity of the nutritive quality of the processed product but also on the extra financial benefits resulting from the wet fractionation process. The value-added primary products from the fractionation process ensure extra return to the. forage producers, crop processing installation and the feedlot operation. The characteristics of the fractionation products derived from lucerne and other crops are described.
Integrated Grazing Of Goats With Sheep Or Cattle On Continuously Grazed Pasture, A M. Nicol, A.J F. Russel, I A. Wright
Integrated Grazing Of Goats With Sheep Or Cattle On Continuously Grazed Pasture, A M. Nicol, A.J F. Russel, I A. Wright
IGC Proceedings (1993-2023)
Oroups of ewes (10) and their twin lambs were grazed on sown ryegrass• white clover (Lolium perenne L.-Trifollum repens L.) pastures maintained at a sward surface height of 4 or 8 cm and a further group grazed with yearling goats (in a proportion of 1/3 ewe plus lamb live weight) also at fi cm. A second concurrent experiment consisted of 3 similar treatments using young cattle with sward surface heights of 8 and 12 cm. Results over the 140-day grazing period showed that allhough the diet selected by sheep and cattle grazed with goats contained more green grass …
Herbage And Animal Production From Tall Fescue- And Ryegrass-Based Pastures In A Summer-Dry Environment, D E. Hume, R.J M. Hay, T B. Lyons
Herbage And Animal Production From Tall Fescue- And Ryegrass-Based Pastures In A Summer-Dry Environment, D E. Hume, R.J M. Hay, T B. Lyons
IGC Proceedings (1993-2023)
Herbage production and animal performance were measured over 3 years In Hawkes Bay, a summer-dry region of New Z'.ealand. Tall rescue (Festuca arundinacea) (3 cultivars, all endophyte free) was compared with high endophyte perennial ryegrass (Lolium perenne). All pastures were sown with white clover (Trifolium repens). Herbage production and composition were determined for all seasons while cattle were monitored for live-weight gains from spring through to autumn. Tall fescue pastures produced 27% more total dry matter/ year than the ryegrass pasture, primarily in autumn. In summerautumn, ryegrass pastures had up to 76% dead matter …
Pasture Production Of Annual, Hybrid And Perennial Ryegrasses In Cool And Warm Temperature Climates, D E. Hume, M J. Hickey
Pasture Production Of Annual, Hybrid And Perennial Ryegrasses In Cool And Warm Temperature Climates, D E. Hume, M J. Hickey
IGC Proceedings (1993-2023)
Pasture production and persistence of 8 ryegrass species-cultivars were evaluated under 2 grazing frequencies (infrequent and frequent) in a cool temperate climate (Southland) and a warm temperate climate (Manawatu) in New Zealand. All pastures were sown with white clover (Trifolirim repe11s) and rotationally grazed with sheep for 3 years. The 8 ryegrass lines were divided botanically into cultivars of annual ryegrass (Lo/ium muftljlorum), hybrid ryegrass (L. boucl1eanu111) (most of the parentage derived from L. multiflorum) and perennial ryegrass (L. pere,me). Infrequent grazing resulted in higher yields and particularly higher ryegrass yields, but lower ryegrass tiller numbers at the cool site. …
Influence Of Sward Height On The Mechanics Of Grazing And Intake Rate By Racehorses, T P. Hughes, J R. Gallagher
Influence Of Sward Height On The Mechanics Of Grazing And Intake Rate By Racehorses, T P. Hughes, J R. Gallagher
IGC Proceedings (1993-2023)
Indoor studies were conducted with harvested turfs to evaluate the effect of sward height on the mechanics of grazing and Intake rate of racehorses. Bile weight increased from 0.64 g DM at the lowest sward height of 13.1 cm to 1.29 g DM at the highest sward height, 29,2 cm. Bite rate declined from 57.9 bites/min at the lowest sward height to 37.4 bites/min at the highest. This decline in bite rate as sward height Increased reflected increasing depth of bite, bite volume and bile weight. Intake rate did not increase with increasing sward height, It was concluded that this …
Changes In Pasture Composition In Semi-Arid Environments Due To Soil Fertility, P C. Kerridge, J G. Mcivor
Changes In Pasture Composition In Semi-Arid Environments Due To Soil Fertility, P C. Kerridge, J G. Mcivor
IGC Proceedings (1993-2023)
The changes in the yield and botanical composition after the sowing of grass and legume species into cleared native woodland in 2 longterm grazing trials are presented and discussed. Soil fertility, rainfall and method of establishment all affected pasture composition. Increasing the soil fertility through phosphate application was necessary for sustained production of sown grass and also improved legume performance.
Nitrogen Recovery Of Coastal Bermudagrass As Influenced By Sulphur Fertilization, J M. Phillips, W E. Sabbe
Nitrogen Recovery Of Coastal Bermudagrass As Influenced By Sulphur Fertilization, J M. Phillips, W E. Sabbe
IGC Proceedings (1993-2023)
Research was conducted during 2 growing seasons to determine N and S fertiliser recovery of Coastal bermudagrnss (Cynodon dactylon (L.) Pers.) on ft $-deficient Rilla silt loam (fine-silty, mixed, thcrmic Typic Hnpludalf) soil in the Gulf Coastal Plain of the south-eastern USA, S wns applied as gypsum or wettable S at the annual Initiation of fornge growth at 100 kg S/ha, N wu applied as ammonium nitrute (NH4NO3),_ urea, and 32% urea-ammonium nitrate (UAN) solution at rates of 0, 224, and 448 kg N/ha in 4 split applications. N sources did not significantly influence Nor S recovery. However, both …
Climate Change: Adapting Tropical And Subtropical Grasslands, G M. Mckeon, S M. Howden, N.O J. Abel, J M. King
Climate Change: Adapting Tropical And Subtropical Grasslands, G M. Mckeon, S M. Howden, N.O J. Abel, J M. King
IGC Proceedings (1993-2023)
Climate change as a result of increasing greenhouse gas concentrations or lhe repetition of historical climale variability will affect the management and production of tropical and subtropical grasslands that support about half the world's domestic herbivores. Previous studies of the regional impact of climate change and climate variability on intensive agriculture have shown lhat such evaluation should include the known and expected abilities of managers and governments to respond by reducing the negative impacts and taking advantage of positive opportunities, A high priority for grassland scientists is the development of similar evaluation capabilities for grassland systems, which are more complex …
Evaluating The Effects Of Climate Changes On Grasslands, Robert G. Woodmansee, William E. Riebsame
Evaluating The Effects Of Climate Changes On Grasslands, Robert G. Woodmansee, William E. Riebsame
IGC Proceedings (1993-2023)
Determining the effects of climate change on cold region grasslands requires the integration of knowledge from the biological, physical and social sciences. That integration is dependent on new methods, technologies and facilitation techniques ! that allow evaluation and management of complexity rather than focusing on simplification. Specifically, grassland response can be defined as the interaction of 10 basic sectors: (I) wenther and climate (Including chemical factors}, (2) winter, (3) soil properties, (4) assemblages of organisms, (5) energy, (6) economic viability, (7) individual human behavior, (8) cultural and community viability, (9) organisational penalty, and (10) political, legal, policy, and regulatory Influences. …
Greenhouse Gas Exchanges With Temperate Grassland Systems, S C. Jarvis, D J. Hatch, G J. Dollard
Greenhouse Gas Exchanges With Temperate Grassland Systems, S C. Jarvis, D J. Hatch, G J. Dollard
IGC Proceedings (1993-2023)
Preliminary studies are described which examine the fluxes of two important greenhouse gases from grassland systems, In the first, effects of different slurry application methods to a peat soil on the emission of N2O were examined. All methods resulted in a significant release of N20 at rates which varied with treatment, time and environmental conditions. The greatest rates of denitrification occurred with acidified slurry under wet conditions: this however, produced the lowest proportion of losses as N2O, In the second study, changes in CH4 concentration above a grazed sward were measured and indicated a definite positive flux from the system …
Methane Production By New Zealand Ruminants, K Betteridge, M J. Ulyatt, J Knapp, R L. Baldwin
Methane Production By New Zealand Ruminants, K Betteridge, M J. Ulyatt, J Knapp, R L. Baldwin
IGC Proceedings (1993-2023)
Methane production by ruminants in New Zealand was estimated using a ma1hema1ical model of rumen digestion interfaced with census livestock numbers. New Zealand was divided into 4 climatic regions with each classified into improved, unimproved and tussock grasslands, and livestock were allocated to each class at appropriate stocking rates. Models of changing livestock numbers within n year were developed for each animal and land class. Food dry matter intake for each class of livestock was calculated from estimates of feed requirements and diet quality. Total methane production was estimated to be 1.50 Tg per year: 58.4% sheep, 20.7%, beef cattle, …
Vertical And Diurnal Profiles Of Atmospheric Carbon Dioxide Concentrations In Manawatu, New Zealand, C C. Bell
Vertical And Diurnal Profiles Of Atmospheric Carbon Dioxide Concentrations In Manawatu, New Zealand, C C. Bell
IGC Proceedings (1993-2023)
Carbon dioxide concentrations were monitored at 2 heights above pasture, at Flock House, New Zealand using an infrared gas analyzer attached to a multiport sampler, Characteristic profiles for a calm day and a windy day are presented. At low wind speeds there was a marked diurnal cycle in CO2 concentration with a maximum difference of 336 ppm between day and night concentrations. An elevated CO2 concentration· was evident for some hours after sunrise. At higher wind speeds the CO2 cycle was less marked, with only a 20 ppm difference between day and night levels. At times, plants are exposed to …
Nitrous Oxide Emissions From Grassland In Manawatu, New Zealand, R A. Carran, J P. Evans
Nitrous Oxide Emissions From Grassland In Manawatu, New Zealand, R A. Carran, J P. Evans
IGC Proceedings (1993-2023)
Nitrous oxide (Np) is a minor component of the atmosphere which acts as a potent greenhouse gas and also causes ozone depletion. Soil bacteria are the most important agents of N2O production, but both the New Zealand and the international data on N2O emission rates from soils are very poor at present. In order to help define the possible range of emission ranges from pasture soils· we selected sites with characteristics that would make then "high" or "low" emitters of N2O. The "high" emission site was a fine-textured, fertile but poorly drained flood plain soil. The "low" emission site was …
Changing Stocking Rates And Burning Management To Reduce Greenhouse Gas Emissions From Southern Queensland Grasslands, S M. Howden, G M. Mckeon, J C. Scanlan, J O. Carter, D H. White
Changing Stocking Rates And Burning Management To Reduce Greenhouse Gas Emissions From Southern Queensland Grasslands, S M. Howden, G M. Mckeon, J C. Scanlan, J O. Carter, D H. White
IGC Proceedings (1993-2023)
GRASSMAN, an agricultural decision-support model, has been modified to include sources, sinks and storages of greenhouse gases. The modified model was used to investigate the effects of changes in stocking rate and burning management on greenhouse gas emissions of southern Queensland grasslands. These grasslands are significant net emitters of greenhouse gases in their natural state, resulting in large differences between net and anthropogenic (man-made) emissions and hence, to different conclusions regarding emission reduction strategies. At moderate stocking rates, anthropogenic emissions could be reduced by about 20% with little loss of productivity. However, similar reductions in net emissions require larger management …
Development Of Plants Resistant To Insect Pests Using Gene Manipulation, D.W R. White, D R. Biggs, M T. Mcmanus, C R. Voisey, J T. Christeller, A H. Broadwell, E.P J. Burgess, C N. Chilcott, P J. Wigley, P G. Mcgregor
Development Of Plants Resistant To Insect Pests Using Gene Manipulation, D.W R. White, D R. Biggs, M T. Mcmanus, C R. Voisey, J T. Christeller, A H. Broadwell, E.P J. Burgess, C N. Chilcott, P J. Wigley, P G. Mcgregor
IGC Proceedings (1993-2023)
Damage to pasture plants caused by insect pests reduces the supply of feed for grassland animal production. In addition, the use of chemical insecticides for the control of pasture pests is undesirable for reasons of high cost and possible damage to the environment. One way to overcome these limitations is 10 utilize a recent development. in plant molecular biology which has seen the incorporation of cloned genes that confer insect _pest resistance into crop plants. To date, the most widely used genes for this purpose are those coding for insecticidal proteins from the bacterium Bacillus thuringiensis, and for inhibitors …
Genetically Engineer Protection Against Viruses And Fungi, John Fitchen, Roger N. Beachy
Genetically Engineer Protection Against Viruses And Fungi, John Fitchen, Roger N. Beachy
IGC Proceedings (1993-2023)
The first examples of plant genetic engineering for disease resistance were for the control of virus diseases. Plants that were transformed with a gene to express the coat protein of tobacco mosaic virus (TMV) were shown to have increased resistance to infection by TMV. This approach, referred to as coat protein-mediated resistance (CP-MR), has been applied to give protection against at least 35 different viruses, belonging to 12 virus groups in at least 13 plant species. Field trials of some of these examples have demonstrated that CP-MR can effectively protect plants under field conditions. Other viral genes have also been …
Bermudagrass Allelochemistry And Influence On Spodoptera Frugiperda Herbivory, S Quisenberry, M Mohamed
Bermudagrass Allelochemistry And Influence On Spodoptera Frugiperda Herbivory, S Quisenberry, M Mohamed
IGC Proceedings (1993-2023)
Cultivated area of bermudagrass (Cynodon dactylon L. Pers.), in the USA are under stress from a complex of insect and secondary fungal pests which has resulted in a loss in crop production. The fall armyworm (Spodoptera frugiperda (J.E. Smith)) is the major insect herbivore of bermudagrass in the south-eastern USA. Bermudagrass breeding programmes over the last decade have yielded germplasm with potential insect-resistant traits. Thus, a programme was initiated to define bermudagrass allelochemislry with respect to insect herbivory. Pall armyworm is variably responsive to bermudagrass cultivars, the basis being causally related to a differential concentration of the phagostimulant 6, …
Purification And Characterization Of A Proteinase Inhibitor From Lolium Perenne L., Mohammed Tasneem, C A. Cornford, M T. Mcmanus, D W.R White
Purification And Characterization Of A Proteinase Inhibitor From Lolium Perenne L., Mohammed Tasneem, C A. Cornford, M T. Mcmanus, D W.R White
IGC Proceedings (1993-2023)
A proteinase inhibitor from dry seeds of Lolium perenne L. cv. Grasslands Ruanui has been partially purified and characterised. Standard protein separalion techniques have been used to enrich the presence of lhe inhibitor in seed extracts by 37-fold. Using synthetic substrates the inhibitor can retard the activity of bovine chymotrypsin, but not bovine trypsin. Gel filtration column chromatography indicates that the native protein has a molecular weight of c. 20 KDa.
Hypervariable Mini-Chromosomes Of Colletotrichum Gloeosporidoides Infecting The Pasture Legume Genus Stylosanthes, John M. Manners, Andrew Masel, John A.G Irwin
Hypervariable Mini-Chromosomes Of Colletotrichum Gloeosporidoides Infecting The Pasture Legume Genus Stylosanthes, John M. Manners, Andrew Masel, John A.G Irwin
IGC Proceedings (1993-2023)
Coiletotrichum gloeosporioides causes anthracnose disease of the tropical pasture legumes Stylosanthes, Two pathotypes and multiple physiological races are present in Australia. The mechanisms producing genetic variation in this pathogen are not understood. Electrophoretic karyotyping has revealed considerable variation in the size and number of a group of small chromosomes (0.2-1.2 Mb in size) both between and within types. Molecular analysis of a selected mini-chromosome using chromosome-specific DNA probes suggests that it has originated by horizontal transfer from a genetically distinct strain. This mini-chromosome is unique to race 3 within the Type B pathogen and may determine race specificity. A functional …
Coat Protein-Mediated Protection Against White Clover Mosaic Virus And Potato Virus X In Tobacco, D L. Beck, C J. Van Dolleweerd, B Dudas, D R.W White, R.L S. Forster
Coat Protein-Mediated Protection Against White Clover Mosaic Virus And Potato Virus X In Tobacco, D L. Beck, C J. Van Dolleweerd, B Dudas, D R.W White, R.L S. Forster
IGC Proceedings (1993-2023)
The coat protein genes of the potexviruses white clover mosaic virus (WClMY) or potato virus X (PVX) were introduced into Nicotiana benthamiana plants by gene transfer. Transgenic plants expressing the coal protein gene of WCIMY or PYX were highly resistant to infection when challenge-inoculated with the virus from which the coat protein gene was obtained (homologous challenge). Similar resistance was obtained when homologous viral RNA was used as inoculum, The transgenic plants were also protected against infection with the heterologous virus, but only at low inoculum concentrations. The level of protection in PYX transgenic plants was directly correlated with the …