Agronomy and Crop Sciences Commons^™

Modulation Of The Gibberellin Content In Transgenic Turf-Type Bahiagrass For Improved Turf Characteristics And Reduced Mowing Requirements, F. Altpeter, M. Agharkar, H. Zhang

IGC Proceedings (1977-2023)

Bahiagrass is extensively used for utility turf along highways and for residential lawns in the southern USA and in the subtropical regions around the world. The objective of this experiment was to enhance turf quality of bahiagrass and reduce the mowing frequency by over-expression of a gibberellin catabolizing enzyme, Gibberellin 2-oxidase.

LxrTm White Clover: Development Of Transgenic White Clover (Trifolium Repens) With Delayed Leaf Senescence, Y. H. Lin, J. Chalmers, E. Ludlow, C. Pallaghy, G. E. Schrauf, Pablo Rush, A. M. García, A. Mouradov, G. C. Spangenberg

IGC Proceedings (1977-2023)

Leaf senescence is a type of programmed cell death characterized by loss of chlorophyll, lipids, protein, and RNA. Cytokinins are a class of plant hormones that play roles in many aspects of plant growth and development, including leaf senescence, apical dominance, the formation and activity of shoot meristems, nutrient mobilization, seed germination, and pathogen responses. They also appear to mediate a number of light- regulated processes, such as de-etiolation and chloroplast differentiation. It is known that the concentrations of endogenous cytokinins decline in plant tissues as senescence progresses. This observation provides the opportunity to manipulate the senescence program in transgenic …

Production And Analysis Of Transgenic White Clover (Trifolium Repens) Plants Over-Expressing Organic Acid Biosynthetic Genes, C. M. Labandera, Stephen N. Panter, A. Winkworth, J. Simmonds, A. Mouradov, U. John, P. W. Sale, G. C. Spangenberg

IGC Proceedings (1977-2023)

Aluminium (Al) toxicity is a major environmental limitation for plant production in acid soils, which represent more than one third of the world’s agricultural land. Al-induced secretion in roots of organic acids (OA), such as malate and citrate, chelates the toxic Al cation excluding it from the root. This mechanism of Al-tolerance appears also to be associated with enhanced P-use efficiency. The development of transgenic plants for enhanced synthesis and secretion of OA from roots is a promising approach to confer Al-tolerance and enhanced P-acquisition efficiency. In order to understand the association between OA biosynthesis and secretion from roots in …

Minimising Bloat Through Development Of White Clover (T. Repens) With High Levels Of Condensed Tannins, M. T. O’Donoghue, C. Spillane, E. Guiney

IGC Proceedings (1977-2023)

White clover constitutes a low percentage of the overall sward content in Irish pastureland despite EU directives limiting the use of nitrogenous fertilizers. This is mainly due to the tendency of large amounts of white clover to cause bloat. Bloat is a potentially fatal build up of proteinaceous foam in the guts of ruminants. Some lesser cultivated legumes such as Lotus species contain condensed tannins (CT) that decrease the incidence of bloated animals. The project’s objective is to reduce the risk of bloat by generating white clover cultivars with high CT content. We are investigating whether expression of the ANTHOCYANIN …

Polyphenolic Phenomena: Transgenic Analysis Of Some Of The Factors That Regulate The Cell-Specific Accumulation Of Condensed Tannins (Proanthocyanidins) In Forage Crops, Mark P. Robbins, G. Allison, D. Bryant, P. Morris

IGC Proceedings (1977-2023)

Condensed tannins biosynthesised within crops are a well-established mechanism for protecting plant protein in the rumen of grazing livestock. Protein protection mediated by these polymeric flavonoid molecules has been characterised in Lotus spp. and offers an interesting contrast to the polyphenol oxidase (PPO) system that confers protein protection in red clover.

Molecular Breeding Of Transgenic Virus-Immune White Clover (Trifolium Repens) Cultivars, M. Emmerling, P. Chu, K. F. Smith, C. Binnion, M. Ponnampalam, P. Measham, Z. Y. Lin, N. R. Bannan, T. C. Wilkinson, G. C. Spangenberg

IGC Proceedings (1977-2023)

White clover (T. repens L.) is a major component of improved pastures throughout the temperate world. It is, however, highly susceptible to virus infection. Alfalfa mosaic virus (AMV), clover yellow vein virus (CYVV) and white clover mosaic virus (WCMV) all contribute to a significant reduction in dry matter yield and persistence of white clover. Sources of natural resistance to AMV in white clover or sexually compatible species are not available. Pathogen-derived resistance strategies, such as the expression of viral coat protein in transgenic plants, thus provides opportunities for the development of virus immune transgenic white clover.

Identification Of Quantitative Trait Loci For Flowering Time In A Field-Grown Lolium Perene X Lolium Multiflorum Mapping Population, R. N. Brown, R. E. Barker, S. E. Warnke, L. A. Brilman, M. A. R. Mian, S. C. Sim, G. Jung

IGC Proceedings (1977-2023)

Perennial ryegrass (L. perenne) and annual, or Italian, ryegrass (L. multiflorum) are considered to be separate species by the seed trade, and are used and bred for distinct purposes. However, the two species are cross-fertile. Seed producers rely on the different flowering times of the two species to produce pure seed. Flowering times can overlap, leading to genetic mixing. Contamination of perennial ryegrass seed lots with annual types is an expensive problem for grass seed producers in western Oregon, USA.

Approaches For Associating Molecular Polymorphisms With Phenotypic Traits Based On Linkage Disequilibrium In Natural Populations Of Lolium Perenne, L. Skøt, J. Humphreys, I. P. Armstead, M. O. Humphreys, J. A. Gallagher, I. D. Thomas

IGC Proceedings (1977-2023)

Association mapping relies on linkage disequilibrium (LD) between haplotypes and quantitative trait loci (QTL). The level of LD in a genome determines the resolution of this approach. In out-breeding species, LD is expected to decay rapidly, thus allowing for high-resolution mapping. It has been most extensively used in human genetics, but recent work with maize populations has demonstrated its potential in plants (Thornsberry et al., 2001; Wilson et al., 2004), and used in L. perenne to identify AFLP markers associated with a major QTL for heading date on linkage group 7 (Skøt et al., 2004). The objective …

Quantitative Trait Loci For Vegetative Traits In Perennial Ryegrass (Lolium Perenne L.), A. M. Sartie, H. S. Easton, Marty J. Faville, C. Matthew

IGC Proceedings (1977-2023)

Physiological (EP) research in forage grasses relates traits such as leaf elongation rate (LER), leaf elongation duration (LED), and leaf appearance interval (ALf), to forage yield (Chapman & Lemaire, 1993). This paper reveals preliminary quantitative trait locus (QTL) discovery for eight EP traits in perennial ryegrass. It also investigates the potential role of multivariate analyses such as principal component analysis (PCA) in QTL analysis of EP data.

Mapping Water-Soluble Carbohydrate Content In Perennial Ryegrass, L. Turner, J. Gallagher, I. P. Armstead, A. Cairns, M. O. Humphreys

IGC Proceedings (1977-2023)

Perennial ryegrass (Lolium perenne L.) is the main species used in UK agriculture and shows considerable genetic variation for water-soluble carbohydrate (WSC) content (Humphreys, 1989, Turner et al., 2001, 2002). High-sugar grasses have already proved useful in UK livestock production (Miller et al., 2001), but can be unpredictable in the field. Increased understanding of carbon partitioning in ryegrass would benefit future breeding programmes.

Changes In Gene Expression During Acclimation To Cold Temperatures In White Clover (Trifolium Repens L.), M. Lowe, R. P. Collins, M. T. Abberton

IGC Proceedings (1977-2023)

White clover is an important component of many temperate pastures and improved winter hardiness is a major objective of breeding programmes in many countries. Exposure to cold and fluctuations in temperature are components of winter stress and although some studies have investigated the agronomic and physiological mechanisms of cold tolerance, little research has been carried out to identify the genes involved. We are complementing mapping of quantitative trait loci (QTL) responsible for cold tolerance with studies of variation in gene expression between plants growing at different temperatures. In particular we are initially focusing on the process of acclimation by analysing …

Estimation Of The Coefficient Of Double-Reduction In Autotetraploid Lucerne, R. Ayadi, P. Barre, Christian Huyghe, B. Julier

IGC Proceedings (1977-2023)

Polyploidy plays an important role in the evolution of species and many cultivated species, particularly in angiosperms, are polyploids (Bever and Felber, 1992; Gallais, 2003). Autopolyploid species that show a tetrasomic inheritance have complex genetics. However, some theoretical models were built for: (1) genetic mapping (Hackett et al., 1998), (2) quantitative genetics (Gallais, 2003) and (3) population genetics (Ronfort et al., 1998). But in practice, most data analyses ignore one essential feature of tetrasomic inheritance that is double-reduction. Indeed, in an autotetraploid species, homologous chromosomes can form tetravalents at meiosis. In this case, a double-reduction is observed if …

Development Of Est-Derived Simple Sequence Repeat (Ssr) Markers In Italian Ryegrass (Lolium Multiflorum Lam.), M. Hirata, Y. Miura, T. Takamizo, M. Fujimori

IGC Proceedings (1977-2023)

Italian ryegrass (IRG, Lolium multiflorum Lam.) is an important grass species used for agricultural purposes in Japan. Linkage maps in IRG have been constructed using molecular markers including RFLPs, AFLPs (Inoue et al., 2003) and genomic SSRs. The SSR marker is a useful tool for genome analysis because it is PCR-based with a relatively high level of polymorphism, co-dominantly expressed. The EST-SSR markers are expected to be more conserved and have a higher rate of transferability than genomic SSR markers (Scott et al., 2000), and the gene functions of ESTs may be predicted. Ikeda et al. (2004) …

Improvement Of Native Perennial Forage Plants For Sustainability Of Mediterranean Farming Systems, F. Lelièvre, Florence Volaire

IGC Proceedings (1977-2023)

The amount of water available to agriculture in the Mediterranean is declining because of increasing population pressure and greater incidence of drought. Therefore, the efficiency of the use of water for agricultural production must be maximized and, in this context, perennial forage species have a number of advantages in comparison to the predominantly-used annuals. They can utilize water throughout the whole year besides being able to halt rangeland degradation, restore soil fertility and enhance forage production, thereby contributing to greater sustainability of rain-fed agricultural systems in the southern European Union and North Africa. Despite these advantages, the small size of …

The Potential For Summer-Dormant Perennial Grasses In Mediterranean And Semi-Arid Pastures, F. Lelièvre, Florence Volaire, P. Chapon, M. Norton

IGC Proceedings (1977-2023)

In rain-fed Mediterranean and semi-arid areas, herbage production of perennial grasses depends on their ability to grow efficiently during the rainy seasons and to persist over the dry summer. A key survival strategy in these harsh conditions is summer dormancy (Volaire, 2002). Within the species Dactylis glomerata L., two cultivars (cvs.), contrasting in this trait, were compared in order to analyse their suitability in terms of yield and survival in these environments.

Future Directions In The Molecular Breeding Of Forage And Turf, G. C. Spangenberg, J. W. Forster, D. Edwards, U. John, A. Mouradov, M. Emmerling, J. Batley, S. Felitti, N. O. I. Cogan, K. F. Smith, M. P. Dobrowolski

IGC Proceedings (1977-2023)

Key points

1. Molecular breeding of forage and turf plants and their endosymbionts has entered the post-genomic era with a large amount of structural genomics information and genomic resources available for key forage and turf species and relevant model systems.
2. A primary future challenge is the conversion of this information into useful functional knowledge for the development of molecular breeding technologies and products that address a range of high impact outcome scenarios in forage and turf.
3. High-throughput approaches for spatial and temporal analysis, from genome to phenome, and the respective data integration in a systems biology context will be critical for …

Crown Rust Resistance In Transgenic Italian Ryegrass (L. Multiflorum) Expressing A Rice Chitinase Gene And Crosses With Cytoplasmic Male Sterile Hybrid Ryegrass, W. Takahashi, M. Fujimori, Y. Miura, T. Komatsu, S. Sugita, A. Arakawa, Y. Nishizawa, H. Sato, Y. Mano, T. Hibi, T. Takamizo

IGC Proceedings (1977-2023)

Italian ryegrass (Lolium multiflorum Lam.) is one of the most important forage grasses in the temperate region. In ryegrasses, crown rust (Puccinia coronata) is the most serious foliar fungal disease and brings about a reduction of herbage yield and loss of palatability to grass-eating domestic animals. In this study, we tried to increase tolerance to the pathogen by introducing a rice chitinase gene using particle bombardment.

Genetic And Molecular Characterization Of Temperate And Tropical Forage Maize Inbred Lines, B. Alarcón-Zúñiga, E. Valadez-Moctezuma, T. Cervantes-Martinez, T. Cervantes-Santana, M. Mendoza‐Rodriguez

IGC Proceedings (1977-2023)

Livestock feeding in the Central highland of Mexico is based on harvest, grazing and annual forage conservation, with forage maize being the most important silage crop (Alarcón, 1995). Even though forage maize is extensively bred in Europe, USA and Asia since the 1900’s, this started in Mexico only in the 1960’s, and little is known about genetic diversity in both agronomic and nutritive value traits. Our breeding program goals are to analyze combining ability of biomass and quality predictors and to study the genetic relationship of inbred lines between lowland tropical and temperate races from Mesa Central, by genetic and …

The Use Of Molecular Markers In Genetic Variability Analysis Of A Collection Of Dactylis Glomerata L., R. Costa, G. Pereira, C. Vicente, M. M. Tavares De Sousa

IGC Proceedings (1977-2023)

Dactylis glomerata L. is one of the three most used perennial grasses in Europe (jointly with Lolium perenne and Festuca arundinacea). The main qualities of Dactylis glomerata are high productivity in pure cultures, high level of proteins and tolerance to drought, cold and shade (Mousset & Chosson, 1986). In the last ten years, techniques that allow direct discrimination at the DNA level have encouraged the study of the genetic variability within cultivated populations as well as identification of the diversity available in germplasm banks. DNA polymorphisms have been shown to be efficient in the identification of genetic variability in …

Molecular Characterization And Tissue Culture Regeneration Ability Of The Usa Arachis Pintoi (Krap. And Greg.) Germplasm Collection, M. A. Carvalho, K. H. Quesenberry, M. Gallo-Meagher

IGC Proceedings (1977-2023)

Arachis pintoi Krap. and Greg. is a herbaceous, perennial legume, exclusively native to Brazil. It is considered a multiple use legume, being grown for forage; ground cover in fruits orchards, forest, and low tillage systems; erosion control; and ornamental purposes. Although several cultivars have been released in different countries, little is known about the genetic diversity of the germplasm stored in world genebanks. Our objective was to characterize and evaluate the genetic diversity of the germplasm of 35 accessions of Arachis pintoi at molecular level using RAPD markers. Concurrently, two tissue culture protocols were evaluated for their organogenesis ability. Further, …