Agricultural Science Commons^™

Eating Biodiversity: Investigating The Links Between Grassland Biodiversity And Quality Food Production, A. Hopkins, H. Buller, C. Morris, J. D. Wood

IGC Proceedings (1977-2023)

Modern food production systems are generally detrimental to biodiversity, and the widespread loss of species-diverse grassland as a consequence of intensive farming methods is well documented. Since the 1980s, a range of policy measures and financial incentives for farmers have been introduced in Europe to halt (and in some cases, reverse) this trend, primarily to meet environmental objectives of species and habitat conservation and landscape protection. Biodiversity, where associated with agricultural production, has largely been regarded as a positive 'externality' to the process of food production; a ‘product’ which benefits wider society without necessarily conferring an agricultural benefit to the …

Do Species And Functional Diversity Indices Reflect Changes In Grazing Regimes And Climatic Conditions In Northeastern Spain?, F. De Bello, J. Leps, M. T. Sebastià

IGC Proceedings (1977-2023)

Understanding the mechanisms that maintain biodiversity in various ecosystems enables the development of management practices that prevent degradation (Canals & Sebastia, 2000). Each diversity index reflects some compositional properties and could be influenced differently by stress and disturbance factors (Magurran, 2004). In this study, we aim to reveal 1) which management practices and environmental factors affect biodiversity in rangelands of northeastern Spain and 2) the relationship between species diversity and functional diversity (SD and FD).

The Biodiversity Value Of ‘Improved’ And ‘Unimproved’ Saline Agricultural Land And Adjacent Remnant Vegetation In South Australia, M. L. Hebart, N. J. Edwards, E. A. Abraham, A. D. Craig

IGC Proceedings (1977-2023)

Since European settlement of the Upper South-east of South Australia, the distribution and abundance of much of the native flora and fauna of the region has been affected by clearing of native vegetation and drainage of wetlands to facilitate agricultural production. Only 8.3% of the original vegetation and less than 7% of the original swamps now remain in the region and much of what is left exists as small isolated remnants (Croft & Carpenter, 1996). Furthermore, as a consequence of the demise of large areas of agriculturally productive lucerne in the late 1970’s and early 1980’s, the rise of saline …

Soil, Plant And Livestock Interactions In Australian Tropical Savannas, L. P. Hunt, T. Z. Dawes-Gromadzki

IGC Proceedings (1977-2023)

This paper considers the various soil, plant and livestock interactions occurring in Australia’s wet-dry savanna rangelands. These regions are relatively intact compared to most of the world’s rangelands. However there is increasing pressure for more intensive use of the landscape, especially from pastoralism. This potentially threatens landscape health, function and productivity through reduced soil health and a loss of digestible perennial plants, especially given the low soil fertility and highly variable rainfall characteristic of these regions. There is an obvious need for understanding these impacts to devise sustainable management practices that promote soil health and viable perennial plant communities, and …

Grazing Impacts On Rangeland Condition In Semi-Arid South-Western Africa, A. Rothauge, G. N. Smit, A. L. Abate

IGC Proceedings (1977-2023)

The savannah biome, consisting of a dense herbaceous layer and a relatively open woody layer in competitive balance, constitutes 64% of the land surface of Namibia, an arid country in south-western Africa, and is used mainly for extensive cattle and sheep ranching. About half of the savannah area is affected by dense to moderately dense bush-thickening, resulting in a ten-fold decrease in the rangeland’s grass-based carrying capacity and a concomitant loss in meat production of about US$115 million per year (De Klerk, 2004). Bushencroached areas typically have densities > 2 000 bushes/ha with > 90% belonging to a single species. High grazing …

A Decision Support System For Rangeland Management In Degrading Environments, R. G. Bennett, F. J. Mitchell

IGC Proceedings (1977-2023)

The continued viability and productivity of commercial and emerging agriculture in KwaZulu-Natal Province, South Africa, depends on the accurate assessment and sustainable utilization of available natural resources. Sustainability implies that growth and development must take place, and be maintained over time, within the limits set by natural ecosystems. Utilizing an extensive GIS database, field surveys and remote sensing technology, a land assessment decision support system (LADSS) has been developed in an attempt to define these limits for the Province. This system has been developed to assess the appropriate use of existing resources as well as the suitability of current land …

Marker-Assisted Selection For Fibre Concentration In Smooth Bromegrass, C. Stendal, M. D. Casler, G. Jung

IGC Proceedings (1977-2023)

The concentration of neutral detergent fibre is the best single laboratory predictor of voluntary intake potential in forage crops. However, the assay of thousands of plant samples for NDF selection in a breeding program requires a large amount of labour and time, potentially increasing cycle time and reducing the rate of progress. A previous study (Diaby and Casler, 2005) identified 16 random amplified polymorphic DNA (RAPD) markers that were strongly associated with NDF concentration in one or more of four smooth bromegrass (Bromus inermis Leyss) populations. The objective of this study was to validate these associations by implementing marker-assisted …

Modelling The Encroachment Of Farmhouse Culture On Private Village Pastures And Its Environmental Fall-Out In Northern Western Ghats, India, S. B. Nalavade, K. R. Sahasrabuddhe, A. A. Patwardhan

IGC Proceedings (1977-2023)

Tropical India harbours numerous pasturelands across small landholdings ranging up to few hectares which are covered with grass that is suitable as fodder. These grazing lands are commonly known as ‘Gairan’ in urbanised northern Western Ghats mountain tract in Western India). Such grasslands comprise about 20% of the total area of a village (Jodha, 1986), support livestock and supplement the agro-economy of the village. These pasturelands are being replaced by fenced ‘farmhouses’ of the urban elite, resulting in land use changes that caused drastic qualitative and quantitative changes in terms of area, fodder species composition and livestock they …

Andean Pastures In The Fourth Region Of Chile: Marginal Lands And Vital Spaces For A Transhumance System, T. S. Koné, R. Osorio, J. -M. Fotsing

IGC Proceedings (1977-2023)

In the fourth region of Chile, the high Andean pastures between Chile and Argentina are the summer destination for transhumant shepherds and sustain a part of the regional livestock. Since 2000, Chile has prohibited the passage of livestock to Argentina for animal health reasons in spite of official registers indicating that 60 to 75% of the summer transhumance livestock had an Argentine destination. Under those conditions it is questionable whether the Andean Chilean grasslands can absorb the increased pastoral demand without suffering damage. The objective is to provide elements of an answer to this question regarding the distribution and availability …

Rangeland As A Common Property Resource: Contrasting Insights From Communal Areas Of Central Eastern Cape Province, South Africa, J. E. Bennett, H. R. Barrett

IGC Proceedings (1977-2023)

In communal areas of South Africa, grazing systems are held under a variety of different common property regimes. However, the social and ecological realities of these communal grazing systems remain poorly understood, particularly with regard to the use of land allocated for crop production. Little is known about how these arable areas are utilised as a common grazing resource but the wide array of tenure arrangements under which they are held suggests that they facilitate some interesting departures from recognised common property systems. A clearer understanding of how common property regimes function at an integrated level in South Africa will …

Australian Pasture Systems: The Perennial Compromise, L. W. Bell, M. A. Ewing

IGC Proceedings (1977-2023)

Dryland salinity, soil acidification and weed herbicide resistance challenge traditional agricultural production systems in south Australia. The pasture component of such systems rely on annuals like Trifolium subterraneum and Medicago spp. Replacing annual with perennial pastures allows some redress of the sustainability challenges, but few well-adapted species are available (Ewing & Dolling 2003). A range of perennial species are under evaluation to supplement current options. Some of these new perennial pastures may need modified production systems that allow full expression of their productive potential, especially when integrated with annual crops including cereals, pulses and oil seeds. Integrated systems rely on …

Grazing, Biodiversity And Pastoral Vegetation In The South Sudanien Area Of Burkina Faso, E. Botoni-Liehoun, P. Daget

IGC Proceedings (1977-2023)

Grazing impact on plant diversity is dominated by two contradictory views. In some studies, it has been found to lead to an increase in diversity and in other studies to a decrease associated with dominance of a few species (Nösberger et al., 1998, Hiernaux, 1998). In an Isoberlinia doka forest ecosystem, considered as the climax vegetation in the South Sudanien area of Burkina Faso, a study was carried out to assess the impact of grazing on the diversity of herbaceous species. The Isoberlinia doka forest is one type of South Sudanien savanna. The woody stratum is open and allowed …

Optimization Of The Pasture Resource In Boundary Environments As A Basis For Regional Nature Management, M. V. Rogova

IGC Proceedings (1977-2023)

In spite of the globalization processes encompassing all spheres of human life and activity, land remains the main resource and provides the feeding source for population and the fodder base for livestock rearing. On the other hand, the activity of local communities can have important global consequences. The study area that includes Lake Baikal’s western shore (East Siberia) and the lake’s largest island exemplifies the traditional type of nature management, namely, grazing management which was originated by an indigenous population within the context of suitable natural climatic conditions. This investigation furnished an opportunity to make an assessment of the status …

Effects Of Landscape Structure On Plants Species Richness In Small Grassland Remnants In Two Different Landscapes, S. A. O. Cousins, O. Eriksson

IGC Proceedings (1977-2023)

There is an increasing interest in using the landscape as the operational scale in many ecological studies. Current species richness in the landscape may be explained by past land use, and habitats may harbour species favoured by an environment that no longer exists. In this study we have included both a landscape scale and a temporal scale. The objective was to explain species pattern and the effect of isolation, habitat size and surrounding land use, and past land use change, on small grassland remnants in rural landscapes.

The Effect Of Alternative Soil Amendments On The Botanical Composition, Basal Cover, Dry Matter Production And Chemical Properties Of Re-Vegetated Mine Land, Wayne F. Truter, N. F. G. Rethman

IGC Proceedings (1977-2023)

Coal mining impacts large grassland areas of the Mpumalanga Province of South Africa. To mitigate such impacts, it is imperative to restore the once productive soils to the best possible condition. The revegetation of mine land presents a particular challenge. Soils being rehabilitated are often acidic and nutrientdeficient, which are major limiting factors in re-vegetation programmes. Conventional methods of liming and inorganic fertilisation have been used to improve the productivity of impacted soils. In the past few years the use of a coal combustion by-product, class F fly ash, and an organic material, such as sewage sludge, have demonstrated the …

Tall Fescue Expressed Sequence Tag And Simple Sequence Repeats: Important Resources For Grass Species, Malay C. Saha, J. C. Zwonitzer, K. Chekhovskiy, M. A. R. Mian

IGC Proceedings (1977-2023)

Expressed sequence tag (EST) databases have been growing exponentially. The simple sequence repeat (SSR) has become one of the most useful molecular marker systems in plant breeding and is widely used in cultivar fingerprinting, genetic diversity assessment, molecular mapping and marker-assisted selection. ESTs are a potential source for SSRs. The EST-SSR markers are of high quality and have versatile applications in molecular breeding (Bughrara et al., 2003; Saha et al., 2004 a, b, c). Here, we present an overview of our efforts to develop SSRs from tall fescue ESTs and their application for the genetic improvement of forage …

Repulsion-Phase Linkage Analysis Of Tetraploid Creeping Bentgrass (Agrostis Stolonifera L.), S. E. Warnke, N. Chakraborty, G. Jung

IGC Proceedings (1977-2023)

Creeping bentgrass is a cool-season grass species primarily used on golf course greens, tees, and fairways because of its tolerance of low mowing heights and recuperative ability. Creeping bentgrass is tetraploid and outcrossing and has been characterized as having bivalent chromosome pairing through cytogenetic analysis (Jones, 1956) and disomic inheritance based on the inheritance of isozyme markers (Warnke et al., 1998). The objective of this experiment was to evaluate the extent of repulsion-phase linkages of single dose AFLP type markers in a creeping bentgrass mapping population and to infer chromosome pairing behaviour based on the ratio of coupling to …

A Core Aflp Map Of Aposporic Tetraploid Paspalum Notatum (Bahiagrass), J. P. A. Ortiz, J. Stein, E. J. Martínez, S. C. Pessino, C. L. Quarin

IGC Proceedings (1977-2023)

Paspalum notatum (Bahiagrass) is a perennial rhizomatous species that reproduces by aposporous apomixis. Tetraploid races (2n=4x=40) are widely distributed from Central to South America and constitute one of the most valuable natural forage grasses for the subtropical areas of Paraguay, southern Brazil and north-eastern Argentina. Apospory in the species is controlled by a single locus, which exhibits a distorted segregation ratio. The objectives of this work were to develop a core genetic linkage map of the species by using AFLP markers and characterize the genomic region related to apospory.

Towards A Genetic Map In Creeping Bentgrass Based On Ssrs, Aflps And Rflps, H. Zhao, S. Bughrara

IGC Proceedings (1977-2023)

Creeping bentgrass (Agrostis palustris) (2n=4x=28) is commonly used in golf course, putting green, tees and fairways. In spite of the importance of the species in turfgrass industry, the genetic study of the creeping bentgrass has received relatively little attention. Genetic mapping, as a new tool, helps traditional turfgrass breeding methods through the construction of linkage, identification of quantitative trait loci linked to traits of interest, and application of marker assisted selection program. Molecular markers such as AFLPs, SSRs and RFLPs have been used extensively for the preparation of linkage maps of a number of crop species. The objective …

Integration Of Perennial Ryegrass (L. Perenne) Genetic Maps Using Gene-Associated Snps, A. C. Vecchies, R. C. Ponting, M. C. Drayton, N. O. I. Cogan, K. F. Smith, G. C. Spangenberg, J. W. Forster

IGC Proceedings (1977-2023)

The reference genetic map of perennial ryegrass was developed by the International Lolium Genome Initiative (ILGI), using the p150/112 one-way pseudo-testcross population. A selection of public domain genetic markers including RFLPs, detected by wheat, barley, oat and rice cDNA probes, and AFLPs were mapped, allowing studies of comparative relationships between perennial ryegrass and other Poaceae species. The map was enhanced through the addition of unique perennial ryegrass genomic DNA-derived SSR (LPSSR) markers, providing the basis of framework genetic mapping in other populations. In addition, a small number of RFLP loci detected by candidate genes involved in herbage quality traits were …

Construction And Comparison Of Genetic Linkage Maps Of Four F1 Populations Of Italian Ryegrass (Lolium Multiflorum Lam.), M. Vandewalle

IGC Proceedings (1977-2023)

The objective of this work was to integrate genetic maps and QTL-positions within 4 two-way pseudo-testcross F1 populations (each 110 genotypes) of Italian ryegrass (Lolium multiflorum) To integrate genetic maps and QTL-positions within the 4 populations and to the ILGI reference map, the maps used for initial QTL-analysis and marker assisted selection for yield and for different quality traits were further evaluated.

Qtls For Morphogenetic Traits In Medicago Truncatula, B. Julier, T. Huguet, J. M. Prosperi, P. Barre, Christian Huyghe, G. Cardinet

IGC Proceedings (1977-2023)

Plant morphogenesis that includes growth, development and flowering date, drives a large number of agronomical important traits in both grain and forage crops. Quantitative trait locus (QTL) mapping is a way to locate zones of the genome that are involved in the variations observed in a segregating population. Co-location of QTLs and candidate genes is an indication of the involvement of the genes in the variation. The objective of this study was to analyse segregation of aerial morphogenetic traits in a mapping population of recombinant inbred lines of the model legume species M. truncatula , to locate QTLs and candidate …

A Comprehensive Analysis Of Gene Expression And Genomic Alterations In A Newly Formed Autotetraploid Of Paspalum Notatum, L. G. Martelotto, J. P. A. Ortiz, F. Espinoza, C. L. Quarin, S. C. Pessino

IGC Proceedings (1977-2023)

The proportion of angiosperms that have experienced one or more episodes of chromosome doubling is estimated to be of the order of 50-70%. This prominence of polyploidy probably implies some adaptive significance. The emergence of novel phenotypes could allow polyploids to enter new niches or enhance their chances of being selected for use in agriculture. Although the causes of novel variation in polyploids are not well understood, they could involve changes in gene expression through dosage-regulation, altered regulatory interactions and rapid genetic/epigenetic changes. The objective of this work was to carry out an extensive transcript profiling and genome analysis of …

Effects Of Sowing Date And Phosphorus Fertiliser Application On Winter Survival Of Lucerne Cv. Aohan In The Northern Semi-Arid Region Of China, Z. L. Wang, Q. Zh. Sun, Y. W. Wang, Zh. Y. Li, Sh. F. Zhao

IGC Proceedings (1977-2023)

In the northern semi-arid region of China, winter survival is always a limiting factor for lucerne production, because low temperatures and a dry climate in winter (Zhou et al., 1993; Ma, 2000; Sun & Gui, 2001; Sun et al., 2003). An experiment was conducted to find an appropriate sowing date and P application rate in order to improve lucerne winter survival.

Characterisation Of Perennial Ryegrass Parental Inbred Lines For Generating Recombinant Inbred Lines For Fine Mapping And Gene Cloning, U. C. M. Anhalt, S. Barth, T. Schwarzacher, J. S. Heslop-Harrison

IGC Proceedings (1977-2023)

Intermated recombinant inbred lines (IRIs) are a powerful tool for fine mapping and cloning of genes. Such population structures have been particularly helpful for cloning of genes in the model genetic plant Arabidopsis thaliana. IRIs or recombinant inbred lines (RILs) would be valuable for perennial ryegrass (Lolium perenne), but its allogamous character means that the construction of RILs is a difficult task. The international Lolium community would benefit from the development of such lines. The aims of the projects are to characterise the parental lines and initial generations at the (1) phenotypic, (2) molecular and (3) molecular …

A High-Density Ssr Linkage Map Of Red Clover And Its Transferability To Other Legumes, S. Isobe, S. Sato, E. Asamizu, I. Klimenko, N. N. Kozlov, K. Okumura, S. Tabata

IGC Proceedings (1977-2023)

A high-density linkage map of red clover was constructed based on SSR and RFLP markers. In order to construct a linkage map with user (breeder) friendly markers; i.e. informative and easy detection, two policies were adopted for marker development. One was that the markers should be derived from cDNA or gene-rich regions, and the other was that the SSR markers should be detected polymorphisms on agarose gels. We also discuss the transferability of the markers on the map to other red clover germplasm and legumes. Such highly transferable markers could be used to screen anchor markers for both on a …

Development Of Est And Aflp Markers Linked To A Gene For Resistance To Ryegrass Blast (Pyricularia Sp.) In Italian Ryegrass (Lolium Multiflorum Lam.), Y. Miura, C. Ding, R. Ozaki, M. Hirata, M. Fujimori, H. Cai, K. Mizuno

IGC Proceedings (1977-2023)

Ryegrass blast, caused by the fungus Pyricularia sp. is one of the most serious diseases of Italian ryegrass (Lolium multiflorum Lam.). However, in Italian ryegrass, except for a new cultivar ‘Sachiaoba’, no resistant cultivars were found in Japan (Mizuno et al., 2003). For these reasons, improving the disease resistance of Italian ryegrass is one of the most important goals in the breeding programs. The aim of this study was to identify genes for resistance to ryegrass blast and to develop EST and AFLP markers linked tightly to the resistance genes.

Qtl Analysis And Trait Dissection In Ryegrass (Lolium Spp.), T. Yamada, J. W. Forster

IGC Proceedings (1977-2023)

Key points

1. Molecular marker-based genetic analysis permits the dissection of complex phenotypes through resolution of the locations of pleiotropic and interacting genetic factors.
2. Several QTLs for agronomically important characters such as flowering time, winter hardiness and forage quality have been identified in perennial ryegrass by molecular marker-based map analysis.
3. Some QTLs were putatively orthologous to those for equivalent traits in cereals.
4. The identification of co-location between QTLs and functionally-associated genetic markers is critical for the future implementation of marker-assisted selection programs.

Construction And Exploitation Of A Bacterial Artificial Chromosome (Bac) Library For Lolium Perenne (Perennial Ryegrass), K. Farrar, A. M. Thomas, M. O. Humphreys, I. S. Donnison

IGC Proceedings (1977-2023)

BAC libraries are an important tool in genomics, enabling physical maps, genome sequencing, marker development and map based cloning strategies. A BAC library has therefore been generated for the temperate grass species Lolium perenne (perennial ryegrass) which compliments an existing BAC library of the closely related species, Festuca pratensis also generated by IGER. Moreover the L. perenne BAC library will provide a useful tool for grass comparative genomics to compliment the existing BAC libraries of cereal crops including rice, wheat, barley, Sorghum and maize. In particular it will allow a comparison of micro-synteny between this large genome forage crop species …

Introgression Mapping In The Grasses, I. P. King, J. King, I. P. Armstead, J. A. Harper, L. A. Roberts, H. Thomas, H. J. Ougham, R. N. Jones, A. Thomas, B. J. Moore, L. Huang, I. S. Donnison

IGC Proceedings (1977-2023)

Key points

1. Lolium perenne/Festuca pratensis hybrids and their derivatives provide an ideal system for intergeneric introgression.
2. The Lolium perenne/Festuca pratensis system is being exploited to elucidate genome organisation in the grasses, determination of the genetic control of target traits and the isolation of markers for MAS in breeding programmes.
3. The potential of the system as an aid to contig the Lolium and Festuca genomes and for gene isolation is discussed.