Showing papers on "Molecular breeding published in 2001"

Improving plant breeding with exotic genetic libraries

Abstract: Naturally occurring variation among wild relatives of cultivated crops is an under-exploited resource in plant breeding. Here, I argue that exotic libraries, which consist of marker-defined genomic regions taken from wild species and introgressed onto the background of elite crop lines, provide plant breeders with an important opportunity to improve the agricultural performance of modern crop varieties. These libraries can also act as reagents for the discovery and characterization of genes that underlie traits of agricultural value.

Quantitative genetics, genomics and plant breeding

Abstract: 1: Vignettes of the history of genetics Part I: Genomics, Quantitative Trait Loci, and Tissue Culture 2: Quantitative genetics, genomics and the future of plant breeding 3: Why quantitative geneticists should care about bioinformatics 4: QTL analysis: problems and (possible) solutions 5: Association mapping in plant populations 6: Integrating molecular techniques into quantitative genetics and plant breeding 7: Use of molecular markers in plant breeding: drought tolerance improvements in tropical maize 8: Explorations with barley genome maps 9: Global view of QTS/QTLS: rice as a model 10: Marker-assisted backcross breeding: a case-study in genotype building theory 11: Complexity, quantitative traits and plant breeding: a role for simulation modelling in the genetic improvement of crops 12: Linking bio physical and genetic models to integrate physiology, molecular biology and plant breeding 13: Tissue culture for crop improvement 14: Transferring genes from wild species into rice 15: Genotype environment interaction: progress and prospects 16: Analysing QTL - by environment interaction by factorial regression, with an application to the CIMMYT drought and low-nitrogen stress programme in maize 17: Elements of genotype - environment interaction: genetic components of the photoperiod response in maize 18: Mechanisms of improved nitrogen use efficiency in cereals 19: Biplot analysis of multi-environment trial data 20: Linear-bilinear models for the analysis of genotype - environment interaction 21: Exploring variety - environment data using random effects AMMI models with adjustments for spatial field trend: Part 1: Theory 22: Exploring variety - environment data using random effects AMMI models with adjustments for spatial field trend: Part 2: Applications 23: Applications of mixed models in plant breeding 24: Defining adaptation strategies and yield stability targets in breeding programmes

Molecular breeding: the natural approach to protein design.

Abstract: Publisher Summary This chapter reveals the advances in protein design termed “molecular breeding,” allows protein engineers to homologously recombine multiple related genes by a process that closely mimics sexual recombination to generate functionally diverse libraries of chimeric proteins from which improved variants can be selected. Molecular breeding effects the permutation of diversity within a pool of related sequences and has proven to be an extraordinarily effective method to evolve proteins and pathways for better function. The most widely used format for molecular breeding is in vitro fragmentation and reassembly of DNA. The highly active, functionally diverse gene libraries generated by molecular breeding have extended directed evolution to a plethora of proteins for which only limited throughput screens are feasible. The chapter discusses the method for molecular breeding involves recombination of homologous genes obtained from nature, in order to permutate the proven diversity. Molecular breeding (also called DNA shuffling) was developed to mimic this essential feature of natural evolution.

In Vitro Plant Breeding

Abstract: Contents * Foreword * Preface * Chapter 1. Introduction * Types of In Vitro Culture * Applications of Plant Tissue Culture * Chapter 2. Morphogenesis/Organogenesis * Introduction * Plant Growth * Cellular Differentiation * Morphogenesis * Chapter 3. Micropropagation * Definition * Stages in Micropropagation * Commercial Micropropagation * Applications of Micropropagation * Chapter 4. Haploid Plant Production In Vitro * Anatomy of Anther * Anther Culture * Androgenesis * Chapter 5. In Vitro Pollination and Fertilization * Development of Female Gametophyte * Pollination * Fertilization * Embryo Culture * Chapter 6. Somatic Hybridization Using Protoplast Technology * Introduction * Uses of Protoplast Technology * Obtaining Protoplasts * The Culture of Protoplasts * The Cytoplasmic Genomes * Common Potential of Protoplast Fusion * Chapter 7. Cell Culture and Selection of Desirable Traits * Selection of Naturally Occurring Variants in Culture * General Selection Strategies * Chapter 8. In Vitro Mutagenesis * Types of Mutagens * Determining the Type and Suitable Concentration of Mutagens * The Choice of Plant Tissues for In Vitro Mutagensis * Chapter 9. The Origin, Nature, and Significance of Variation in Tissue Culture * Introduction * The Basis of Somaclonal Variations * Causes of Somaclonal Variations * Use of Somaclonal Variation in Breeding * Prevention of Somaclonal Variation * Chapter 10. Cryopreservation and Plant Breeding * Introduction * Theory and Technology * Cryopreservation Protocols for Cold-Hardy and Non-Cold-Hardy Species * Storage and Thawing * Equipment for Cryopreservation * Practical Issues and Strategies Toward Improved Cryoprotection * Chapter 11. In Vitro Micrografting * Definition of Micrografting * Analysis of Compatibility and Incompatibility Phenomena * Chapter 12. In Vitro Flowering: Its Relevance to Plant Breeding * Factors Influencing In Vitro Flowering * Plant Growth Regulators * Mineral Nutrients and Other Medium Components * Explant, Light, and Other Variables * Application of In Vitro Flowering to Plant Breeding * Chapter 13. In Vitro Tuberization * Introduction * Factors Controlling Microtuber Production * Practical Aspects of In Vitro Tuberization * Chapter 14. Molecular Plant Breeding * Types of Molecular Markers * Major Objectives of Molecular Breeding * Applications of Molecular Markers in Plant Breeding * Case Study: Application of Molecular Markers in Barley (Hordeum vulgare) Breeding * References * Index

Molecular Breeding of Forage Crops

Abstract: Forage plant breeding has been largely based on phenotypic selection following sexual recombination of natural genetic variation found between and within ecotypes. Advances in plant genetic manipulation over the last 15 years have provided convincing evidence that these powerful technologies can complement and enhance plant breeding programs. Significant progress in the establishment of the methodologies required for the molecular breeding of forage plants has been made. Examples of current products and approaches for the application of these methodologies to forage grass and legume improvement are outlined. Large-scale genomic analysis of many organisms is under way with human, arabidopsis and rice genome sequences almost completed . Forage plant breeding is just now entering the genome era. The plethora of new technologies and tools now available for high-throughput gene discovery and genome-wide gene expression analysis have opened up opportunities for innovative applications in the identification, functional characterisation and use of genes of value in forage production systems and beyond. Examples of these opportunities, such as 'molecular phenotyping', ' symbio-genomics' and 'xeno-genomics ' are introduced. G. Spangenberg (ed.), Molecular Breeding 01Forage Crops , 1-39. © 2001 Kluwer Academic Publishers.

Breeding forage plants in the genome era.

Abstract: Forage plant breeding has been largely based on phenotypic selection following sexual recombination of natural genetic variation found between and within ecotypes. Advances in plant genetic manipulation over the last 15 years have provided convincing evidence that these powerful technologies can complement and enhance plant breeding programs. Significant progress in the establishment of the methodologies required for the molecular breeding of forage plants has been made. Examples of current products and approaches for the application of these methodologies to forage grass and legume improvement are outlined. Large-scale genomic analysis of many organisms is under way with human, arabidopsis and rice genome sequences almost completed. Forage plant breeding is just now entering the genome era. The plethora of new technologies and tools now available for high-throughput gene discovery and genome-wide gene expression analysis have opened up opportunities for innovative applications in the identification, functional characterisation and use of genes of value in forage production systems and beyond. Examples of these opportunities, such as ‘molecular phenotyping’, ‘symbio-genomics’ and ‘xeno-genomics’ are introduced.

Gene Tagging with Random Amplified Polymorphic DNA (RAPD) Markers for Molecular Breeding in Plants

Abstract: Markers are of interest to plant breeders as a source of genetic information on crops and for use in indirect selection of traits to which the markers are linked. In the classic breeding approach, the markers were invariably the visible morphological and other phenotypic characters, and the breeders expended considerable effort and time in refining the crosses as the tight linkage or association of the desired characters with the obvious phenotypic characters was never unequivocally established. Furthermore, indirect selection for a trait using such morphological markers was not practical due to (1) a paucity of suitable markers, (2) the undesirable pleiotropic effects of many morphological markers on plant phenotype, and (3) the inability to score multiple morphological mutant traits in a single segregating population. With the advancement in molecular biology, the use of molecular markers in plant breeding has become very commonplace and has given rise to “molecular breeding”. Molecular breeding involve...

Molecular breeding of transposable elements

Abstract: Methods for producing transposable elements with improved properties as vectors are provided. Directed evolution procedures are employed to improve characteristics of transposable elements, including transposons and insertion sequences as vectors. Methods for generating diversity in vivo and in vitro using transposable elements as vectors are provided.

Transgenesis and genomics in molecular breeding of forage plants.

Abstract: Forage plant breeding has been largely based on phenotypic selection following sexual recombination of natural genetic variation found between and within ecotypes. Advances in plant genetic manipulation over the last 15 years have provided convincing evidence that these powerful technologies can complement and enhance plant breeding programs. Significant progress in the establishment of the methodologies required for the molecular breeding of forage plants has been made. Examples of current products and approaches for the application of these methodologies to forage grass and legume improvement are outlined. Large-scale genomic analysis of many organisms is under way with human, arabidopsis and rice genome sequences almost completed. Forage plant breeding is just now entering the genome era. The plethora of new technologies and tools now available for high-throughput gene discovery and genome-wide gene expression analysis have opened up opportunities for innovative applications in the identification, functional characterisation and use of genes of value in forage production systems and beyond. Examples of these opportunities, such as ‘molecular phenotyping’, ‘symbio-genomics’ and ‘xeno-genomics’ are introduced.

Quantitative genetics, genomics and the future of plant breeding.

Abstract: Quantitative genetics (in its various guises) has been the intellectual cornerstone of plant breeding for close to 100 years. While the roots of Mendelian genetics, and its rediscovery, are firmly in the hands of plant breeders, it was Fisher's (1918) variance decomposition paper that marks the modern foundation for both quantitative genetics and plant breeding. We are now embarking on the age of genomics, and so it is reasonable to speculate on the implications of both partial and whole genome sequences for quantitative genetics. Likewise, the tools of modern quantitative genetics have been developed in four separate fields: plant breeding, animal breeding, human genetics, and evolutionary genetics. Unfortunately, for a variety of reasons, migration of information between these fields has not been what it should be. Thus, it is also an appropriate time to inquire whether useful tools have been developed in these other fields that may be helpful to plant breeders of today and the genomics-based breeders of the near future.

Molecular tools for modern ornamental plant breeding and selection

Abstract: Though the development of sophisticated breeding strategies in ornamentals is lagging behind those for most of the agricultural crops, over the last years molecular methods have been quickly adopted. Apart from the use of molecular tools for the identification and verification of varieties two main areas are relevant for ornamental plant breeding. Marker assisted breeding utilises the information of markers linked to genes of interest to develop more efficient selection strategies. This is of particular importance where important traits are difficult to analyse or where simultaneous combinations of several genes are needed (e.g. resistance genes). In addition, the introgression of interesting target genes from wild species genomes may be more efficient with marker assisted selection against the genetic background of the wild donor species. The second area comprises techniques for genetic engineering of ornamental plants. The available gene pool for novel target genes is virtually unlimited in this area and reports on successful transformations are already available for Dianthus, Rosa, Petunia, Dendrathema, Pelargonium and many other ornamentals. For both areas the target traits are mainly centred around disease resistance, stress tolerances, delayed senescence, post harvest performance, novel colours and changed plant architecture. Of main importance for the future availability of genes both for marker assisted selection and for genetic engineering are the results from the ongoing genome projects in model organisms. These provide valuable information on the genetic architecture of flowering plants. The efforts undertaken in these projects also boosted technological developments (like e.g. microarrays, bioinformatic tools, transformation technologies) that will strongly influence ornamental plant breeding in the near future.

Contribution of microsatellites to sugarcane breeding program in Mauritius.

Abstract: Sugar cane microsatellite libraries have recently been developed. Here, we report the efficiency of some rnicrosatellite primers to generate polymorphic and easily scorable markers in sugar cane. Primers selected proved to be very efficient when applied to test for legitimacy of clones, to identify contaminants in nurseries and for diversity studies. We also investigated the amplification of microsatellite primers on DNA extracted using an alkaline treatment method, and this technique looks promising.

Molecular Breeding for Tolerance to Abiotic/Edaphic Stresses in Forage and Turfgrass

Abstract: Perennial grasses will always be subject to fluctuating multiple environmental and soil-related stresses. In most cases, from 100–1000 genes must function to activate the mechanisms governing these stresses. The first target of both conventional and biotechnology breeding efforts should be focused on root system improvement. The first line of defense in grass plant adaptation to these stresses is root plasticity (functional root volume maintenance and viability under cyclic stresses). As stress tolerance mechanisms are better understood, gene technology can be integrated with traditional breeding strategies to locate, sequence, clone, and comparatively map stress-responsive genes, hopefully leading to specific-trait marker assisted selection and overall multiple stress tolerance enhancement in forage and turfgrasses.

Molecular Breeding for Herbage Quality in Forage Crops

Abstract: Relatively small changes in quality of forage crops can lead to large changes in animal performance. Genetic changes in mineral elements, alkaloids, secondary metabolites, cell walls, protein, or energy availability are all possible using a combination of traditional and molecular breeding techniques. Because few major genes are known to regulate herbage quality traits, breeders have traditionally relied on quantitative trait loci (QTL) for genetic improvement of forage crops. A limited number of QTL for herbage quality traits have been mapped in maize (Zea mays L.), perennial ryegrass (Lolium perenne L.), and Pennisetum spp. As more QTL are identified, marker assisted selection for herbage quality may become a useful breeding method. Transgenic technology offers the potential to create genetic variability that does not exist in nature. Antisense cDNA constructs are available for all known enzymes in the phenylpropanoid pathway. Down-regulation of most enzymes leads to reduced lignin concentration or increased syringyl:guaiacyl residue ratios, usually increasing herbage digestibility. Sense cDNA constructs for rumen-stable proteins offer the opportunity to improve protein quality in numerous forage crops. Despite its glamour and potential, transgenic technology adds complexity to a forage breeding program, demanding close collaboration between molecular biologists and field-oriented plant breeders. Transgenic plants must be carefully evaluated for numerous agronomic traits in a wide array of field environments, as well as transgene stability and expression through multiple sexual generations, increasing the time and expense required to develop new cultivars.

Quantitative genetics and breeding methods

Abstract: Plant breeding is an applied science that includes information and techniques from different disciplines, including quantitative genetics, to develop improved cultivars Quantitative genetics itself will not either directly develop superior cultivars or enhance our germplasm resources The principles of quantitative genetics, however, are considered at all stages of plant breeding Parameters have been developed for determining effective population sizes, genetic variability within breeding populations, genetic effects important for inbreeding depression and heterosis, estimation of heritability and predicting future genetic advance, types of genetic effects among different types of hybrids, and selection methods for germplasm enhancement Quantitative genetics is one of the tools available to plant breeders that contributed to the genetic gains realized for most of our important crop species during the 20th century

Approaches for associating molecular polymorphisms with phenotypic traits based on linkage disequilibrium in natural populations of Lolium perenne

Abstract: Skot, L., Humphreys, J., Armstead, I. P., Humphreys, M. O., Gallagher, J. A., Thomas, I. D. (2005). Approaches for associating molecular polymorphisms with phenotypic traits based on linkage disequilibrium in natural populations of Lolium perenne. Page 157 in: Humphreys, M. O. (Ed.). Molecular Breeding for the Genetic Improvement of Forage Crops and Turf. Wageningen Academic Publishers, ISBN: 978-90-76998-73-2. Proceedings of the 4th International Symposium on the Molecular Breeding of Forage and Turf. XXth International Grassland Congress, July 2005, Aberystwyth, Wales.

Genetic Improvement of Switchgrass and Other Herbaceous Plants for Use as Biomass Fuel Feedstock

Abstract: It should be highly feasible to genetically modify the feedstock quality of switchgrass and other herbaceous plants using both conventional and molecular breeding techniques. Effectiveness of breeding to modify herbages of switchgrass and other perennial and annual herbaceous species has already been demonstrated. The use of molecular markers and transformation technology will greatly enhance the capability of breeders to modify the plant structure and cell walls of herbaceous plants. It will be necessary to monitor gene flow to remnant wild populations of plants and have strategies available to curtail gene flow if it becomes a potential problem. It also will be necessary to monitor plant survival and long-term productivity as affected by genetic changes that improve forage quality. Information on the conversion processes that will be used and the biomass characteristics that affect conversion efficiency and rate is absolutely essential as well as information on the relative economic value of specific traits. Because most forage or biomass quality characteristics are highly affected by plant maturity, it is suggested that plant material of specific maturity stages be used in research to determining desirable feedstock quality characteristics. Plant material could be collected at various stages of development from an array of environments and storage conditions that could be used in conversion research. The same plant material could be used to develop NIRS calibrations that could be used by breeders in their selection programs and also to develop criteria for a feedstock quality assessment program. Breeding for improved feedstock quality will likely affect the rate of improvement of biomass production per acre. If the same level of resources are used, multi-trait breeding simply reduces the selection pressure and hence the breeding progress that can be made for a single trait unless all the traits are highly correlated. Since desirable feedstock traits are likely to be similar to IVDMD, it is likely that they will not be highly positively correlated with yield. Hence to achieve target yields and improve specific quality traits, it will likely be necessary to increase the resources available to plant breeders. Marker assisted selection will be extremely useful in breeding for quality traits, particularly for traits that can be affected by modifying a few genes. Genetic markers are going to be needed for monitoring gene flow to wild populations. Transformation will be a very useful tool for determining the affects of specific genes on biomass feedstock quality.

Biotechnology, genetic modification, organic farming and nutrition security

Abstract: The world is witnessing several divides, of which the genetic and nutrition divides are some of the more serious ones. Blending Mendelian and molecular methods of breeding will help to raise the productivity of major crops. Such genetic enhancement coupled with the development of biological software for sustainable agriculture, such as biofertilizers, biopesticides and bioremediation agents, will help to foster an evergreen revolution movement, where productivity is improved in perpetuity without associated ecological or social harm. There are also opportunities for strengthening food-based approaches to bridging the nutrition divide through Mendelian and molecular breeding, as is clear from recent work in the development of quality protein maize, vitamin A-rich rice and protein-rich potato. Biotechnological tools will help farmers with small holdings to take to organic farming. Also, precision agriculture will be strengthened through precision breeding. By integrating pre-breeding in advanced laboratories with participatory breeding with farm families, the advantages of genetic efficiency and diversity can be combined.

Molecular Breeding for Improved Biotic Stress Resistance

Abstract: Molecular breeding of wheat in the sense of genetic engineering will be the subject of this paper It will review actual strategies for engineering fungal resistance in crops An efficient method for genetic transformation of wheat like the biolistic method using immature embryos as target tissue — together with genes that directly or indirectly inhibit the pathogen’s spread — form the basis for the development of transgenic wheat plants with improved fungal resistance

Molecular breeding of forage crops : proceedings of the 2nd Inernational Symposium, Molecular Breeding of Forage Crops, Lorne and Hamilton, Victoria, Australia, November 19-24, 2000

Abstract: Preface. 1. Breeding Forage Plants in the Genome Era G. Spangenberg, et al. 2. Breeding Methods for Forage and Amenity Grasses M.O. Humphreys. 3. Integrating Molecular Techniques to Maximise the Genetic Potential of Forage Legumes D.R. Woodfield, E.C. Brummer. 4. Modelling Plant Breeding Programs: Applications to Forage Crops M. Cooper, et al. 5. Bioinformatics Tools for Genome Projects T. Littlejohn. 6. Development and Implementation of Molecular Markers for Forage Crop Improvement J.W. Forster, et al. 7. Application of Molecular Markers to Genetic Diversity and Identity in Forage Crops R.E. Barker, S.E. Warnke. 8. Genetic Characterization of Heterogeneous Plant Populations in Forage, Turf and Native Grasses D.R. Huff. 9. Development of Molecular Markers for the Analysis of Apomixis H. Nakagawa, M. Ebina. 10. Molecular Breeding for Herbage Quality in Forage Crops M.D. Casler, H.F. Kaeppler. 11. Genetic Manipulation of Condensed Tannin Synthesis in Forage Crops M.Y. Gruber, et al. 12. Molecular Markers for Improving Nutritional Quality of Crop Residues for Ruminants C.T. Hash, et al. 13. Molecular Breeding of Forage Legumes for Virus Resistance R. Kalla, et al. 14. Trangenic Pest and Disease Resistant White Clover Plants C.R. Voisey, et al. 15. Molecular Breeding for Tolerance to Abiotic/Edaphic Stresses in Forage and Turfgrass R.R. Duncan, R.N. Carrow. 16. Molecular Interactions Between Lolium Grasses and Their Fungal Symbionts D.B. Scott. 17. AnIntegrated Functional Genomics and Genetics Approach for the Plant's Function in Symbiotic Nodulation P.M. Gresshoff, et al. 18. The Production of Value-Added Proteins in Transgenic Alfalfa S. Austin-Phillips, T. Ziegelhoffer. 19. Progress and Challenges: Forage Breeding in Temperate Australia K.F.M. Reed, et al. 20. Biosafety Risk Assessment and the Regulatory Framework for the Release of Transgenic Plants N.F. Millis. 21. The Future of Molecular Breeding of Forage Crops M.D. Hayward.