Agronomy and Crop Sciences Commons^™

Livestock Policy In Special Areas, Alberta, Canada, P. L. Strankman

IGC Proceedings (1977-2023)

Special Areas, Alberta, Canada, is a rural municipality of 2.1 million hectares (about 5 million acres) in south-eastern Alberta. It is home to almost 5000 residents, with a unique governance arrangement in Alberta. Most of the farms and ranches utilize a mix of crop and livestock primarily annual cereal and oil seed cultivation and beef cattle. These production units are usually a mosaic of privately-owned land and Crown land leased from the government.

It provides an interesting case study for the local, and national challenges facing western Canadian agriculture. It also provides an opportunity to contrast with different bioclimatic and …

Collaborative Construction Of A Method That Contributes To Improve The Decision Making In Associative Ranches By Controlling The Grass Allowance In A Context Of Climate Variability, Emilio Duarte Esteves, Rómulo Cesar, Javier Fernández, Marcelo Ghelfi, Valentina Herrera, Virginia Caravia, Rodrigo Iribarne, Federico De Brum, Héctor Rodríguez, Marcelo Pereira Machín

IGC Proceedings (1977-2023)

Pasture management and the particular conditions of each year are responsible for productive results, farm income, and condition of the pasture. A simple and robust method that relates the available grass and the required grass was built in a participatory manner, and contributes to a critical reflection process among the group of decision-making, adapting to their context. In 17 farms from the Basalt region in Uruguay, grass and animals were monitored seasonally. A simple method was developed with farmers, and from de offer needed to meet production targets (KgMS/KgPV) the amount of grass requires was calculated. The grass height was …

C3 Perennial Grass Dominates Mixed C3/C4 Grasslands After Invasion By A C3 Woody Sprouter, C. E. Cooper, R. J. Ansley, T. J. Steffens, D. B. Murray, T. Zhang

IGC Proceedings (1977-2023)

Honey mesquite (Prosopis glandulosa) encroachment has resulted in decreased C₄ mid-grass production and increased C₃ mid-grass in the Southern Great Plains of the US. Woody legumes have had similar effects in Africa, Australia, and South America. Prosopis initially facilitates Texas wintergrass (Nassella leucotricha) growth under canopies, in part because N-fixation by this woody legume enriches subcanopy soils, favoring C₃ species. As stand density increases, Nassella extends into interspaces between trees as well. Here we report Nassella responses in several studies that either reduced Prosopis to indirectly impact Nassella or treated Nassella directly. In …

Virus Diseases Of Cereal And Oilseed Crops In Australia: Current Position And Future Challenges, Roger Jones, Murray Sharman, Piotr Trebicki, Solomon Maina, Benjamin S. Congdon

Biosecurity Research Articles

This review summarizes research on virus diseases of cereals and oilseeds in Australia since the 1950s. All viruses known to infect the diverse range of cereal and oilseed crops grown in the continent’s temperate, Mediterranean, subtropical and tropical cropping regions are included. Viruses that occur commonly and have potential to cause the greatest seed yield and quality losses are described in detail, focusing on their biology, epidemiology and management. These are: barley yellow dwarf virus, cereal yellow dwarf virus and wheat streak mosaic virus in wheat, barley, oats, triticale and rye; Johnsongrass mosaic virus in sorghum, maize, sweet corn and …

Increase Of Genetic Variability Of Forage Arachis By Intra And Interspecific Hybridization, J. M. F. Valls, C. M. Castro, M. A. P. Oliveira, C. C. Teixeira

IGC Proceedings (1977-2023)

This study was conducted to examine the potencial to increase the genetic variability of forage Arachis species, involving crosses between accessions of same species and crosses between different species, mostly of distinct taxonomic sections. Hybrids were produced between creeping, stoloniferous accessions belonging to section Caulorrhizae, Arachis pintoi x A. pintoi and A. pintoi x A. repens. Additional crosses involved section Caulorrhizae versus representatives of Erectoides (A. hermannii and A. paraguariensis) and Procumbentes (A. appressipila, A. kretschmeri, A. lignosa and A. vallsii). In intersectional crosses, the stoloniferous accessions were used as male parents. …

Searching For Molecular Markers For Salt Tolerance In Rhodes Grass (Chloris Gayana Kunth), E. Taleisnik, M. Salgado, M. D. Bonafede, L. E. Manghers, H. Pérez, L. García Seffino, A. Castagnaro, D. G. Díaz

IGC Proceedings (1977-2023)

Rhodes grass (Chloris gayana Kunth), a C4 forage grass, is regarded as salttolerant and exhibits intra- and inter-cultivar variability for this trait. Plants of cv Boma were selected for salt tolerance at the seedling and adult stages, cloned and characterized by RAPD and AFLP amplification patterns. Both techniques were equally efficient for fingerprinting these clones. More bands were obtained by AFLP but the ratio of polymorphic bands and the proportion present only in tolerant clones were the same by both methods. These bands, along with those exclusive for sensitive clones could be useful as markers for assisted selection.

Biotechnological Improvement In Timothy Breeding, S. Pulli, Y. D. Guo

IGC Proceedings (1977-2023)

Biotechnological improvements in timothy breeding by androgenic and somatic cell culture and molecular identification were achieved. The doubled haploid (DH) plants were obtained via anther and microspore culture. A series of factors which affect androgenic embryogenesis and green plant regeneration have been evaluated. The PG-96 induction media which sharply promote androgenic embryogenesis have been established. Over 400 DH plants of timothy were obtained. Timothy somatic callus induction was successfully established using immature inflorescences and seedling stems. Suspension cultures were initiated from friable nodule-forming callus. More than 100 regenerated green plants were obtained from somatic callus and suspension clumps. DNA-based fingerprinting …

Evolutionary Recurrent Selection Develops Adapted Annual Ryegrass, G. M. Prine

IGC Proceedings (1977-2023)

Seed companies find having their own annual ryegrass breeding program in the southeastern USA, unprofitable. The annual ryegrass breeding program at the University of Florida provides new annual ryegrass (Lolium multiflorum) cultivars with disease resistance and adaption. The evolutionary recurrent selection breeding uses large nurseries, roguing of diseased and unthrifty plants and selection of best plants to provide seed for the next generation. Current commercial cultivars developed are named along with some of their characteristics.

Chlorophyll Concentration (Spad Values) As An Indicator Of Crude Protein Content And As A Selection Criterion In Grass Breeding, N. Gáborèík

IGC Proceedings (1977-2023)

The main aim of the study was to analyse chlorophyll a + b content (SPAD values) determined by portable chlorophyllmeter (SPAD- 502, Minolta, Japan) and crude protein content in leaves of timothy, coocksfoot, perennial ryegrass and meadow fescue (total 24 cultivars). Differences between both parameters were confirmed and a close relationship between chlorophyll content (SPAD values) and crude protein concentration was found. Correlation coefficient between SPAD and crude protein varied from 0.541⁺⁺ for ryegrass to 0.906⁺⁺ for timothy. This fact should be used for selection of grasses with higher crude protein content and/or better use of mineral soil …

Evaluation Of Red Clover Populations Selected For Persistence And Dry Matter Yield In Rio Grande Do Sul, Brasil, M. Dall’Agnol, D. P. Montardo, J. K. Gonçalves

IGC Proceedings (1977-2023)

Red clover is one of the most important temperate legume species and it is used to alleviate the lack of forage in natural grasslands during the cool season in Rio Gra do Sul, Brasil. However, the lack of persistence presented by this species has not allowed its full utilization. Hence, a breeding program was started to select plants with more persistence and with good dry matter (DM) yield. This work was carried out at the “Estação Experimental Agronômica”, Universidade Federal do Rio Grande do Sul. Three selected red clover populations were evaluated in relation to the best available commercial check, …

Genetic Variation And Genotype By Environment Interaction Of Crown Rust Resistance In Annual Ryegrass (Lolium Multiflorum Lam.), J. De Battista, A. Andrés, S. Giammaría, M. Costa

IGC Proceedings (1977-2023)

The genetic variation and genotype by environment interaction of crown rust resistance of annual ryegrass (Lolium multiflorum Lam.) was evaluated at two locations in Argentina, as part of the breeding programme in progress at our Institute. Forty half sib families originated from commercial tetraploid cultivars, were grown from seeds in a greenhouse during autumn 1999. At the stage of tillering initiation forty eight plants/familiy were randomly selected and transplanted as spaced plant trial in a randomized design with three replicates, at the two locations. All plants were scored for a range of morphological and phytopatological attributes. The severity of …

Differences Between Diploid And Induced Tetraploid Lotus Glaber Mill. (Lotus Tenuis Waldst. & Kit.) Plants, M. S. Barufaldi, H. N. Crosta, M. F. Eseiza, R. H. Rodríguez, E. Sánchez

IGC Proceedings (1977-2023)

Narrowleaf birdsfoot trefoil (Lotus glaber Mill.) is an important forage legume which has spread widely and naturalized in the grasslands of the Depressed Pampas of the Province of Buenos Aires, Argentina. L. glaber is an alogamic diploid species with a low number of chromosomes (2n=2x= 12). These features show it as a species through which induced autopolyploids by colchicine-doubling of seedlings can be obtained. In this paper, we comparatively analyze fertility and size pollen grain, stomata length, central leaflet length and width and central leaflet ratio width/length in diploid plants and induced-autotetraploid plants of L. glaber. The results …

Photoperiod Response In Pensacola Bahiagrass, Ann R. Blount, T. R. Sinclair, R. N. Gates, Kenneth H. Quesenberry, P. Mislevy, R. C. Littell

IGC Proceedings (1977-2023)

Photoperiod response has been found to influence the growth and development of >Pensacola' derived bahiagrass (Paspalum notatum Flugge var. saure Parodi). Four selection cycles [>Pensacola= (Cycle 0), Cycle 4, >Tifton 9' (Cycle 9) and Cycle 23] resulting from recurrent restricted phenotypic selection (RRPS) of spaced-plants, were field grown in 1999 and 2000, to study photoperiod sensitivity among genotypes. Two day-length treatments were imposed on the field grown plants. One treatment, used only natural light. The second treatment imposed an extended day-length treatment using Quartz-halogen lamps, installed in the field during the fall and winter, to extend day-length to15 …

Genetic Variability Within Two Adapted Populations Of Tall Wheatgrass (Thynopyrum Ponticum) In Argentina, A. Andrés, R. Guillen

IGC Proceedings (1977-2023)

The genetic variability within two adapted populations of tall wheatgrass (Thinopyrum ponticum) was evaluated in Argentina, as an introductory part of a breeding programme in progress at our Institute. The final aim of this programme is to provide new cultivars of tall wheatgrass, adapted to different management systems. Two hundred fifty plants per population were grown from seeds, clonally propagated and transplanted as a spaced-plant trial in a randomized design with three replicates. The results indicated large differences between genotypes within the two populations for most attributes measured, though there were no significant differences between populations. Attributes related …

Breeding For Resistance To Strike Leaf Blight (Scolecotrichum Graminis) Of Orchardgras In Argentina, A. Andrés, M. Ruiz Diaz, J. Anonne, B. S. Rosso

IGC Proceedings (1977-2023)

A collection of orchardgrass (Dactylis glomerata) was screened under field conditions for resistance to strike leaf blight (SLB) caused by the fungus Scolecotrichum graminis. On the whole, thirty five entries from different countries were studied by sampling ten genotypes from each origin, clonally propagated and transplanted as spaced-plant trial in a randomized design with two replicates. Plants were periodically assessed during 1996 and 1997 by estimating disease severity (percentage of leaf affected). During 1997, disease severity data were used to calculate the area under disease progress curves (AUDPC) as a complementary attribute to screen for resistance to …

High Polymorphism For Forage Production Of Lotus Corniculatus Sn Transformants, Sergio Arcioni, F. Paolocci, V. Turchetti, F. Damiani

IGC Proceedings (1977-2023)

Transgenic plants obtained from transformation of one individual of Lotus corniculatus with the maize gene Sn, a transactivator of anthocyanin pathway, were analysed for the expression of the transgene and for the accumulation of condensed tannins. A great variability was observed for these two traits. Some extreme individuals were clonally propagated and analysed for rooting ability and plant growth. Unexpectedly, a strong correlation between condensed tannin level, rooting ability and plant growth was observed. These results are discussed in order to explore new strategies to increase plant productivity in forage legumes.

Gastrointestinal Nematode Infections In Grazing Domestic Ruminants, M. Eysker

IGC Proceedings (1977-2023)

World wide gastrointestinal nematode infections impair production of ruminants. Particularly in small ruminants control of these infections is seriously hampered by the development of resistance of the parasites against anthelmintic drugs. This implies that alternative control measures have to be implemented in order to maintain a sustainable ruminant industry. In this paper the various possibilities to achieve this are briefly discussed. The possibilities discussed include grazing management, vaccination, selective breeding, biological control, nutrition and the use of bioactive forages such as for instance plants containing condensed tannins. At the end it is concluded that combinations of these options should preferably …

Plant Secondary Compounds; Their Impact On Forage Nutritive Value And Upon Animal Production, T. N. Barry, D. M. Mcneill, W. C. Mcnabb

IGC Proceedings (1977-2023)

Both the anti-nutritional and beneficial effects of secondary compounds in a range of temperate and tropical forages have been reviewed. Major secondary compounds in temperate and tropical forage plants occur in the phenolic fraction and include condensed and hydrolysable tannins, phenolic monomers and lignin. Condensed tannins (CT) bind to plant protein by pH-reversible hydrogen bonding. In temperate legume forages this reduces rumen protein degradation and can increase the absorption of essential amino acids (EAA) from the small intestine, with reactivity depending on CT concentration, molecular weight and chemical structure. Low concentrations of CT in Lotus corniculatus (20-40g/kg DM) increased EAA …

A Strategy For Detecting Natural Anthelmintic Constituents Of The Grassland Species Plantago Lanceolata, D. L. Gustine, M. A. Sanderson, J. Getzie, S. Donner, R. Gueldner, N. Jennings

IGC Proceedings (1977-2023)

A strategy to detect anthelmintic constituents in plantain (Plantago lanceolata) using a bioassay-driven purification approach was tested. Plantain consumed by cattle may control or reduce internal parasite titers, possibly due to the iridoid glucoside aucubin. Lyophilized, ground leaves of wild P. lanceolata were extracted with 95 % ethanol or boiling water containing calcium carbonate. Partially purified extracts (0 to 250 mg ml^-1), 5 μg ml^-1 of the anthelmintic levamisole, or 5 mg ml^-1 of aucubin were tested with sheathed bovine parasites (Ostertagia ostertagi). The percent moving worms was unchanged for water controls …

Tree Competition Reduces Cattle Growth Rates In Eucalypt Woodlands Of Queensland, T. J. Hall, J. R. Douglas

IGC Proceedings (1977-2023)

The wiregrass/bluegrass (Aristida/Bothriochloa) native pasture community in Eucalypt woodlands is a major cattle producing resource in Queensland. The effects of poplar box tree (Eucalyptus populnea) competition (at 5 m²/ha tree basal area) and grazing pressure on pastures and on growth of Brahman-cross steers were measured in a grazing experiment. Treatments were 2 tree competition levels (live trees or clearing) by 3 grazing pressures (low - 25%, medium - 50% and high - 75% utilisation of annual pasture growth). Pasture yield and pasture foliage cover increased for 3 years from the reduction in tree competition …