Quantitative Genetics in Maize Breeding

ISBN-13: 9781441907653 / Angielski / Twarda / 2010 / 664 str.

Marcelo J. Carena; Arnel R. Hallauer

Opis

Maize is used in an endless list of products that are directly or indirectly related to human nutrition and food security. Maize is grown in producer farms, farmers depend on genetically improved cultivars, and maize breeders develop improved maize cultivars for farmers. Nikolai I. Vavilov defined plant breeding as plant evolution directed by man. Among crops, maize is one of the most successful examples for breeder-directed evolution. Maize is a cross-pollinated species with unique and separate male and female organs allowing techniques from both self and cross-pollinated crops to be utilized. As a consequence, a diverse set of breeding methods can be utilized for the development of various maize cultivar types for all economic conditions (e.g., improved populations, inbred lines, and their hybrids for different types of markets). Maize breeding is the science of maize cultivar development. Public investment in maize breeding from 1865 to 1996 was $3 billion (Crosbie et al., 2004) and the return on investment was $260 billion as a consequence of applied maize breeding, even without full understanding of the genetic basis of heterosis. The principles of quantitative genetics have been successfully applied by maize breeders worldwide to adapt and improve germplasm sources of cultivars for very simple traits (e.g. maize flowering) and very complex ones (e.g., grain yield). For instance, genomic efforts have isolated early-maturing genes and QTL for potential MAS but very simple and low cost phenotypic efforts have caused significant and fast genetic progress across genotypes moving elite tropical and late temperate maize northward with minimal investment. Quantitative genetics has allowed the integration of pre-breeding with cultivar development by characterizing populations genetically, adapting them to places never thought of (e.g., tropical to short-seasons), improving them by all sorts of intra- and inter-population recurrent selection methods, extracting lines with more probability of success, and exploiting inbreeding and heterosis. Quantitative genetics in maize breeding has improved the odds of developing outstanding maize cultivars from genetically broad based improved populations such as B73. The inbred-hybrid concept in maize was a public sector invention 100 years ago and it is still considered one of the greatest achievements in plant breeding. Maize hybrids grown by farmers today are still produced following this methodology and there is still no limit to genetic improvement when most genes are targeted in the breeding process. Heterotic effects are unique for each hybrid and exotic genetic materials (e.g., tropical, early maturing) carry useful alleles for complex traits not present in the B73 genome just sequenced while increasing the genetic diversity of U.S. hybrids. Breeding programs based on classical quantitative genetics and selection methods will be the basis for proving theoretical approaches on breeding plans based on molecular markers. Mating designs still offer large sample sizes when compared to QTL approaches and there is still a need to successful integration of these methods. There is a need to increase the genetic diversity of maize hybrids available in the market (e.g., there is a need to increase the number of early maturing testers in the northern U.S.). Public programs can still develop new and genetically diverse products not available in industry. However, public U.S. maize breeding programs have either been discontinued or are eroding because of decreasing state and federal funding toward basic science. Future significant genetic gains in maize are dependent on the incorporation of useful and unique genetic diversity not available in industry (e.g., NDSU EarlyGEM lines). The integration of pre-breeding methods with cultivar development should enhance future breeding efforts to maintain active public breeding programs not only adapting and improving genetically broad-based germplasm but also developing unique products and training the next generation of maize breeders producing research dissertations directly linked to breeding programs. This is especially important in areas where commercial hybrids are not locally bred. More than ever public and private institutions are encouraged to cooperate in order to share breeding rights, research goals, winter nurseries, managed stress environments, and latest technology for the benefit of producing the best possible hybrids for farmers with the least cost. We have the opportunity to link both classical and modern technology for the benefit of breeding in close cooperation with industry without the need for investing in academic labs and time (e.g., industry labs take a week vs months/years in academic labs for the same work). This volume, as part of the Handbook of Plant Breeding series, aims to increase awareness of the relative value and impact of maize breeding for food, feed, and fuel security. Without breeding programs continuously developing improved germplasm, no technology can develop improved cultivars. Quantitative Genetics in Maize Breeding presents principles and data that can be applied to maximize genetic improvement of germplasm and develop superior genotypes in different crops. The topics included should be of interest of graduate students and breeders conducting research not only on breeding and selection methods but also developing pure lines and hybrid cultivars in crop species. This volume is a unique and permanent contribution to breeders, geneticists, students, policy makers, and land-grant institutions still promoting quality research in applied plant breeding as opposed to promoting grant monies and indirect costs at any short-term cost. The book is dedicated to those who envision the development of the next generation of cultivars with less need of water and inputs, with better nutrition; and with higher percentages of exotic germplasm as well as those that pursue independent research

Spis treści

Preface 1 Introduction 1.1 Quantitative Genetics 1.2 Population Improvement: What do we mean by Recurrent Selection? 1.3 Inbred Line Development 1.4 Conclusions 1.5 References 2 Means and Variances 2.1 Genetically Narrow- vs. Broad-Based Reference Populations 2.2 Hardy-Weinberg Equilibrium 2.3 Means of Non-inbred Populations and Derived Families 2.4 Means of Inbred Populations and Derived Families 2.5 Mean of a Cross between Two Populations 2.6 Average Effect 2.7 Breeding Value 2.8 Genetic Variance 2.9 Means and Variances in Backcross Populations 2.10 Heritability, Genetic Gain, and Usefulness Concepts 2.11 Generation Mean Analysis 2.12 References 3 Resemblance Between Relatives 3.1 Introduction 3.2 Theoretical Basis of Covariance 3.3 Covariance Between Relatives as a Linear Function of Genetic Variances 3.4 References 4 Hereditary Variance: Mating Designs 4.1 Bi-parental Progenies 4.2 Pure Line Progenies (Analysis in self-pollinated crops) 4.3 Parent-Offspring Regressions 4.4 Design I 4.5 Design II 4.6 Design III 4.7 Diallel Methods: The Gardner-Eberhart Analysis II Special Case 4.8 Triple Testcross 4.9 Triallel and Quadrallel 4.10 Inbred Lines 4.11 Selection Experiments 4.12 More on F2 Populations (Special Case of p = q = 0.5) 4.13 Epistasis 4.14 References 5 Hereditary Variance: Experimental Estimates 5.1 Experimental Results 5.2 Iowa Stiff Stalk Synthetic (BSSS) 5.3 Selection Experiments vs. Mating Designs for Prediction 5.4 Epistasis Variance and Effects 5.5 Correlations among Traits and Indirect Selection 5.6 References 6 Selection: Theory 6.1 Selection among Populations 6.2 Selection of Genotypes within Populations 6.3 Intra-population Improvement: Qualitative Traits 6.4 Intra-population Improvement: Quantitative Traits 6.5 Comparing Breeding Methods 6.6 Increasing Gain from Selection 6.7 Correlation among Traits and Correlated Response to Selection 6.8 Multi-Trait Selection 6.9 References 7 Selection: Experimental Results 7.1 Measuring Changes from Selection 7.2 Improvement from Intra-population Selection 7.3 Improvement from Inter-population Selection 7.4 General Effects of Selection 7.5 Factors Affecting Efficiency of Selection 7.6 References 8 Testers and Combining Ability 8.1 Theory 8.2 Correlations between Lines and Hybrids 8.3 Visual Selection 8.4 Genetic Diversity 8.5 Testing Stage 8.6 General vs. Specific Combining Ability 8.7 References 9 Inbreeding 9.1 The Need for Maize Artificial Pollination 9.2 Early Reports of Inbreeding 9.3 Inbreeding Systems 9.4 Inbreeding due to Small Population Size 9.5 Estimates of Inbreeding Depression 9.6 Frequency of Useful Lines 9.7 Types of Hybrids Produced from Inbred Lines 9.8 Heterozygosity and Performance 9.9 References 10 Heterosis 10.1 Introduction and Major Achievements 10.2 Empirical Evidence 10.3 Genetic Basis 10.4 Biometrical Concept 10.5 Heterosis and Prediction Methods across Genotypes 10.6 Components of Heterosis in Intervarietal Diallel Crosses 10.7 Conclusions 10.8 References 11 Germplasm 11.1 Origin of Maize 11.2 Classification of Maize Germplasm 11.3 Races of Maize in the Western Hemisphere 11.4 European Races of Maize 11.5 U.S. Corn Belt Germplasm 11.6 Germplasm Preservation 11.7 Potential and Use of Exotic Germplasm 11.8 References 12 Breeding Plans 12.1 Choice of Germplasm 12.2 Recurrent Selection and Germplasm Improvement 12.3 Integrating Recurrent Selection with Cultivar development 12.4 Intra-population Genetic Improvement 12.5 Inter-population Genetic Improvement 12.6 Additional Considerations for Germplasm Improvement 12.7 Additional Considerations for Inbred Line Development 12.8 References Index

O autorze

Arnel R. Hallauer is C. F. Curtiss Distinguished Professor in Agriculture (Emeritus) at Iowa State University (ISU). Dr. Hallauer has led maize-breeding research for mid-season maturity at ISU since 1958. His work has had a worldwide impact on plant-breeding programs, industry, and students and was named a member of the National Academy of Sciences. Hallauer is a native of Kansas, USA. José B. Miranda Filho is full-professor in the Department of Genetics, Escola Superior de Agricultura Luiz de Queiroz - University of São Paulo located at Piracicaba, Brazil. His research interests have emphasized development of quantitative genetic theory and its application to maize breeding. Miranda Filho is native of Pirassununga, São Paulo, Brazil. M.J. Carena is professor of plant sciences at North Dakota State University (NDSU). Dr. Carena has led maize-breeding research for short-season maturity at NDSU since 1999. This program is currently one the of the few public U.S. programs left integrating pre-breeding with cultivar development and training in applied maize breeding. He teaches Quantitative Genetics and Crop Breeding Techniques at NDSU. Carena is a native of Buenos Aires, Argentina. http://www.ag.ndsu.nodak.edu/plantsci/faculty/Carena.htm

Blurb

Handbook of Plant Breeding Arnel R. Hallauer • Marcelo J. Carena • J.B. Miranda Filho Quantitative Genetics in Maize Breeding Public investment in maize breeding from 1865 to 1996 was $3 billion (Crosbie et al., 2004) and the return on investment was $260 billion as a consequence of applied maize breeding, even without full understanding of the genetic basis of heterosis. Quantitative genetics has allowed the integration of prebreeding with cultivar development by characterizing populations genetically, adapting them to places never thought of (e.g., tropical to short seasons), improving them by all sorts of intra and inter population recurrent selection methods, extracting lines with more prob ability of success, and exploiting inbreeding and heterosis. Quantitative Genetics in Maize Breeding aims to increase awareness of the relative value and impact of maize breeding for food, feed, and fuel security. Without breeding programs continuously developing improved germplasm, no technology can develop improved cultivars. This volume presents principles and data that can be applied to maximize genetic im provement of germplasm and develop superior genotypes in different crops. This is a unique and permanent contribution to breeders, geneti cists, students, policy makers, and land grant institutions still promoting quality research in applied plant breeding as opposed to promoting grant monies and indirect costs at any short term cost. The book is dedicated to those who envision the development of the next generation of cultivars with less need of water and inputs, with better nutrition; and with higher percentages of exotic germplasm as well as those that pursue independent research goals before searching for funding. Arnel R. Hallauer is C. F. Curtiss Distinguished Professor in Agriculture (Emeritus) at Iowa State University (ISU). Dr. Hallauer has led maize breeding research for mid season maturity at ISU since 1958. His work has had a worldwide impact on plant breeding programs, industry, and students and was named a member of the National Academy of Sciences. Hallauer is a native of Kansas, USA. M.J. Carena is professor of plant sciences at North Dakota State University (NDSU). Dr. Carena has led maize breeding research for short season maturity at NDSU since 1999. This program is currently one the of the few public U.S. programs left integrating pre breeding with cultivar development and training in applied maize breeding. He teaches Quantitative Genetics and Crop Breeding Techniques at NDSU. Carena is a native of Buenos Aires, Argentina. http://www.ag.ndsu.nodak.edu/plantsci/faculty/Carena.htm J. B. Miranda Filho is full professor in the Department of Genetics, Escola Superior de Agricultura Luiz de Queiroz University of São Paulo located at Piracicaba, Brazil. His research interests have emphasized development of quantitative genetic theory and its application to maize breeding. Miranda Filho is native of Pirassununga, São Paulo, Brazil. life sciences