Normal view MARC view ISBD view

Application of biotechnology to maize improvement

By: Hoisington, D.A | Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT) Kenya | 7. Proceedings of the Eastern and Southern Africa Regional Maize Conference Nairobi (Kenya) 5-11 Feb 2002.
Contributor(s): Friesen, D.K.|Palmer, A.F.E.
Material type: materialTypeLabelBookAnalytics: Show analyticsPublisher: Nairobi (Kenya) KARI|CIMMYT : 2002Description: p. 7-11.ISBN: 970-648-120-6.Subject(s): Experimentation | Genetic maps | Genomes | Inheritance (genetics) | Maize | Molecular genetics | Plant developmental stages | Technology | Varieties | CIMMYT | KARISummary: This presentation will provide an overview of the application of molecular genetics, genetic engineering and functional genomics to maize improvement. it is not intended to provide comprehensive coverage for the crop, but to give a few concrete examples of how molecular technology has been useful in the genetic dissection and manipulation of important traits in developing improved varieties. Today, scientists can take advantage of genes that are derived from various sources, including related and unrelated species, those identified via genetic mapping experiments and most recently from the efforts of functional genomics (the area aimed at understanding the function on all genes in an organism) (Figure 1 ). Through the application of molecular genetics and genetic engineering, coupled with conventional crossing approaches, these genes can be efficiency incorporated into modern plant varieties. Molecular genetics, or the use of molecular techniques for detecting differences in the DNA of individual plants, has many applications of value to crop improvement. Such molecular makers, when very tightly linked to genes of interest. can be used to indirectly select for the desirable allele, and represents the simplest form of marker-assisted selection (MAS), whether used to accelerate the backcrossing of such an allele or in pyramiding several desirable alleles. Markers can also be used to dissect polygenic traits into their Mendelian components or quantitative trait loci (QTL), thus increasing our understanding of the inheritance and gene action for such traits, and allowing us to use MAS as a complement to conventional selection procedures. Molecular markers are also used to probe the 1evelof genetic diversity among different cultivars, within populations, among related species etc. The applications of such. evaluations are many, including varietal fingerprinting for identification and protection, understanding relationships among the units under study. efficiently managing genetic resources, facilitating introgression of chromosomal segments from alien species, and even tagging of specific genes. In addition, markers and comparative mapping of various species have been very valuable for improving our understanding of genome structure and function and have allowed the isolation of a few genes of interest via map-based cloning. Molecular marker technology has evolved from hybridization-based detection to new sequence-based systems. Each has their advantages and disadvantages. Restriction fragment length polymorphisms (RFLPs) were the first to be developed (some 15 years ago) and have been widely and successfully used to construct linkage maps of various species, including maize and wheat. With the development of the polymerase chain reaction (PCR) technology, several marker types emerged. The first of those were RAPD markers (random amplified polymorphic DNA) which quickly gained popularity over RFLPs due to the simplicity and decreased costs of the assay. However, most researchers now realise the weaknesses of RAPDs and use them with much less frequently. Microsatellite markers or simple sequence repeats (SSRs), combine the power of RFLPs (co-dominant markers, reliable, specific genome location) with the case of RAPDs and have the advantage of detecting higher levels of polymorphism. The AFLP (Amplified Fragment Length Polymorphism) approach takes advantage of the PCR technique to selectively amplify DNA fragments previously digested with one or two restriction enzymes. Playing with the number of selective bases of the primers and considering the number of amplification products per primer pair, this approach is certainly powerful in term~ of polymorphisms identified per reaction. Most recently, systems that detect single base pair changes (termed Single Nucleotide Polymorphisms) are becoming available. While fairly expensive to develop, requiring sequencing of several alleles, they do detect high levels of polymorphism and can be detected with simple and automated technology.Collection: CIMMYT Staff Publications Collection
Tags from this library: No tags from this library for this title. Log in to add tags.
    average rating: 0.0 (0 votes)
Item type Current location Collection Call number Copy number Status Date due Barcode Item holds
Conference proceedings CIMMYT Knowledge Center: John Woolston Library

Lic. Jose Juan Caballero Flores

 

CIMMYT Staff Publications Collection CIS-4159 (Browse shelf) 1 Available 630199
Total holds: 0

This presentation will provide an overview of the application of molecular genetics, genetic engineering and functional genomics to maize improvement. it is not intended to provide comprehensive coverage for the crop, but to give a few concrete examples of how molecular technology has been useful in the genetic dissection and manipulation of important traits in developing improved varieties. Today, scientists can take advantage of genes that are derived from various sources, including related and unrelated species, those identified via genetic mapping experiments and most recently from the efforts of functional genomics (the area aimed at understanding the function on all genes in an organism) (Figure 1 ). Through the application of molecular genetics and genetic engineering, coupled with conventional crossing approaches, these genes can be efficiency incorporated into modern plant varieties. Molecular genetics, or the use of molecular techniques for detecting differences in the DNA of individual plants, has many applications of value to crop improvement. Such molecular makers, when very tightly linked to genes of interest. can be used to indirectly select for the desirable allele, and represents the simplest form of marker-assisted selection (MAS), whether used to accelerate the backcrossing of such an allele or in pyramiding several desirable alleles. Markers can also be used to dissect polygenic traits into their Mendelian components or quantitative trait loci (QTL), thus increasing our understanding of the inheritance and gene action for such traits, and allowing us to use MAS as a complement to conventional selection procedures. Molecular markers are also used to probe the 1evelof genetic diversity among different cultivars, within populations, among related species etc. The applications of such. evaluations are many, including varietal fingerprinting for identification and protection, understanding relationships among the units under study. efficiently managing genetic resources, facilitating introgression of chromosomal segments from alien species, and even tagging of specific genes. In addition, markers and comparative mapping of various species have been very valuable for improving our understanding of genome structure and function and have allowed the isolation of a few genes of interest via map-based cloning. Molecular marker technology has evolved from hybridization-based detection to new sequence-based systems. Each has their advantages and disadvantages. Restriction fragment length polymorphisms (RFLPs) were the first to be developed (some 15 years ago) and have been widely and successfully used to construct linkage maps of various species, including maize and wheat. With the development of the polymerase chain reaction (PCR) technology, several marker types emerged. The first of those were RAPD markers (random amplified polymorphic DNA) which quickly gained popularity over RFLPs due to the simplicity and decreased costs of the assay. However, most researchers now realise the weaknesses of RAPDs and use them with much less frequently. Microsatellite markers or simple sequence repeats (SSRs), combine the power of RFLPs (co-dominant markers, reliable, specific genome location) with the case of RAPDs and have the advantage of detecting higher levels of polymorphism. The AFLP (Amplified Fragment Length Polymorphism) approach takes advantage of the PCR technique to selectively amplify DNA fragments previously digested with one or two restriction enzymes. Playing with the number of selective bases of the primers and considering the number of amplification products per primer pair, this approach is certainly powerful in term~ of polymorphisms identified per reaction. Most recently, systems that detect single base pair changes (termed Single Nucleotide Polymorphisms) are becoming available. While fairly expensive to develop, requiring sequencing of several alleles, they do detect high levels of polymorphism and can be detected with simple and automated technology.

English

0409|AGRIS 0401|AL-Maize Program

Juan Carlos Mendieta

CIMMYT Staff Publications Collection

There are no comments for this item.

Log in to your account to post a comment.
baner

International Maize and Wheat Improvement Center (CIMMYT) © Copyright 2015. Carretera México-Veracruz. Km. 45, El Batán, Texcoco, México, C.P. 56237.
Monday –Friday 9:00 am. 17:00 pm. If you have any question, please contact us at CIMMYT-Knowledge-Center@cgiar.org

Centro Internacional de Mejoramiento de Maíz y Trigo (CIMMYT) © Copyright 2015. Carretera México-Veracruz. Km. 45, El Batán, Texcoco, México, C.P. 56237.
Lunes –Viernes 9:00 am. 17:00 pm. Si tiene cualquier pregunta, contáctenos a CIMMYT-Knowledge-Center@cgiar.org