Evaluation of Elite Maize Inbreds as Sources of Favourable Alleles for the Improvement of Quantitative Traits

Evaluation of Elite Maize Inbreds as Sources of Favourable Alleles for the Improvement of Quantitative Traits PDF Author: Terence Keith Stanger
Publisher:
ISBN:
Category : Corn
Languages : en
Pages : 228

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Evaluation of Elite Maize Inbreds as Sources of Favourable Alleles for the Improvement of Quantitative Traits

Evaluation of Elite Maize Inbreds as Sources of Favourable Alleles for the Improvement of Quantitative Traits PDF Author: Terence Keith Stanger
Publisher:
ISBN:
Category : Corn
Languages : en
Pages : 228

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Quantitative Genetics in Maize Breeding

Quantitative Genetics in Maize Breeding PDF Author: Arnel R. Hallauer
Publisher: Springer Science & Business Media
ISBN: 1441907661
Category : Science
Languages : en
Pages : 669

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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 goals before searching for funding. Scientists are encouraged to use all possible breeding methodologies available (e.g., transgenics, classical breeding, MAS, and all possible combinations could be used with specific sound long and short-term goals on mind) once germplasm is chosen making wise decisions with proven and scientifically sound technologies for assisting current breeding efforts depending on the particular trait under selection. 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

Evaluation of Teosinte Genetic Diversity for Agronomic and Domestication Traits in Maize

Evaluation of Teosinte Genetic Diversity for Agronomic and Domestication Traits in Maize PDF Author: Avinash Karn
Publisher:
ISBN:
Category :
Languages : en
Pages : 166

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Maize (Zea mays ssp. mays) is one of the most important crops in the world. Teosinte (Zea mays ssp. parviglumis) is the wild progenitor of maize and has greater genetic diversity than maize inbreds and landraces. Maize was domesticated from teosinte 9000 years ago, in central Mexico, and has been subjected to modern plant breeding over the past 100 years. In the recent years, extensive scientific breeding practices have led to remarkable yield increases in maize. However, domesticated and artificial genes have greatly reduced genetic diversity and cannot contribute to variation for agronomically important traits. Teosinte readily forms hybrids with maize and thus offers a unique pool of allelic diversity for maize improvement, yet limited genetic resources were available to efficiently evaluate and tap this diversity. To broaden resources for genetic diversity studies in maize, our lab previously developed over 900 near-isogenic introgression lines (NILs) from 10 teosinte accessions in the B73 background, and here we report the development of a new population, the Teosinte Synthetic (Teo-Syn). In order to understand the relationship between genetic diversity from teosinte and grain composition, we evaluated kernel starch, protein, and oil content, in the teosinte NILs. We found two starch, three protein and six oil QTL, which collectively explain 18%, 23% and 45% of the total variation, respectively. A range of strong allelic effects were identified relative to the B73 allele, supporting our hypothesis that teosinte harbors stronger alleles for kernel composition traits than maize. We found that some of the regions of the genome that control grain composition in our population were previously identified in maize, but we also found several new regions of the genome from teosinte that control grain composition. These teosinte alleles can be exploited for the improvement of kernel composition traits in modern maize germplasm. Ultimately, these novel regions of the teosinte genome can be mined for useful variation to improve corn for producers and consumers, as well as many industrial applications. In maize, common variants play a critical role to adapt to numerous large-scale environments; however, there are numerous rare alleles that may contribute to inbreeding depression or heterosis through complementation, or in complex quantitative traits such as yield, adaptation and kernel composition. It is important to understand the role of rare alleles in the maize genetic architecture in order to aid in the selection and development of future elite breeding lines. A new genetic resource, the Teosinte Synthetic (Teo-Syn), was developed by our lab by randomly mating backcrossed (BC1) progeny of 11 parviglumis accessions in the B73 background, yielding a population with the expected genetic ratio of ~25% teosinte and ~75% B73. We identified several significant QTLs for plant architecture, adaptation and kernel composition traits with a wide range of allelic effects. We further investigated if there is any statistical evidence for epistatic interactions in the Teo-Syn population, and found numerous interacting sites with larger and wider effects than additive effects. Maize plays a central role in the US agriculture and food production, as well as has the greatest molecular and phenotypic diversity than any crop species. My results from this study provide accumulated evidence for epistatic interactions influencing the genetic architecture of several plant architecture and composition traits. Findings from this study provide novel information that can be utilized by breeders and geneticist to accelerate the development of future elite maize germplasm as well as provide insight to efficiently predict hybrid performance.

Evaluation of Elite Exotic Maize Inbreds for Use in Long-term Temperate Breeding

Evaluation of Elite Exotic Maize Inbreds for Use in Long-term Temperate Breeding PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The U.S. maize (Zea mays L.) germplasm base is narrow. While maize is a very diverse species, that diversity is not represented in U.S. maize production acreage. Most elite U.S. maize inbreds can be traced back to a small pool of inbreds that were developed decades ago. Increased genetic diversity can be obtained through breeding with exotic germplasm, especially tropical-exotic sources. However, setbacks are often encountered when working with tropical germplasm due to adaptation barriers. Furthermore, the pool of available tropical germplasm is large and diverse, making choices of tropical parents difficult. The maize breeding program at North Carolina State University has begun a large-scale screening effort to evaluate elite exotic maize inbreds, most of which are tropical-exotic in origin. The purpose of this research was to: 1) generate comparative yield-trial data for over 100 elite exotic maize inbreds, 2) determine the relative effectiveness of various testcross regimes, 3) identify sources of gray leaf spot (GLS) resistance among these elite exotic inbreds, and 4) promote the use of exotic maize germplasm to broaden the genetic base of U.S. maize. Over 100 elite exotic maize inbreds were obtained from various international breeding programs. They were tested in replicated yield trials in North Carolina as 50%-exotic testcrosses by crossing them to a broad-base U.S. tester of Stiff Stalk (SS) x non-Stiff Stalk (NSS) origin. The more promising lines additionally entered 25%-tropical testcrosses with SS and NSS testers and were further evaluated in yield-trials. A dozen tropical inbred lines performed well overall--CML10, CML108, CML157Q, CML258, CML264, CML274, CML277, CML341, CML343, CML373, Tzi8, and Tzi9. Inbred lines CML157Q, CML343, CML373, and Tzi9 did not show significant line x tester interaction. Furthermore, it was determined that testcrossing to a single broad-based tester will suffice for initial screening purposes, allowing for elimination.

Developing Drought and Low N-tolerant Maize

Developing Drought and Low N-tolerant Maize PDF Author: G. O. Edmeades
Publisher: CIMMYT
ISBN: 9789686923933
Category : Corn
Languages : en
Pages : 580

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Book Description
Incidence and intensity of drought and low N stresss in the tropics; Case studies strategies for crop production under drought and low n stresses in the tropics; Stress physology and identification of secondary traits; Physiology of low nitrogen stress; Breeding for tolerance to drought and low n stresses; General breeding strategies for stress tolerance; Progress in breeding drought tolerance; Progress in breeding low nitrogen tolerance; Experimental design and software.

Tropical Maize

Tropical Maize PDF Author: R. L. Paliwal
Publisher: Fao
ISBN:
Category : Business & Economics
Languages : en
Pages : 384

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Book Description
Maize is an important crop and the demand for as both food and animal feed is expected to grow by 235 million tonnes between now and 2030. In many countries it will be difficult to increase the area under cultivation, so gains will have to come from increased productivity and intensification of the cropping system. This book looks at all aspects of tropical maize production from physiology, growing environments, pest and diseases, plant breeding and crop management and it is a substantial information resource necessary for the development of the crop.

Advances in Agronomy

Advances in Agronomy PDF Author:
Publisher: Academic Press
ISBN: 0080563724
Category : Technology & Engineering
Languages : en
Pages : 359

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Book Description
Volume 59 contains seven reviews covering key contemporary topics on crop and soil sciences. As always, the topics are varied and exemplary of the array of subject matter covered by this long-running serial. Crop science is represented by chapters on quantitative genetics and plant breeding, wheat, perennial forages, and cotton. These chapters are balanced by synthetic reviews of organoclays in pollution abatement, the applications of micromorphology, and the importance of long-term field research. With this latest volume, Advances in Agronomy continues to be recognized as a leading reference and as a first-rate source of the latest research in agronomy, crop science, and soil science. Quantitative genetics Organoclays and pollution Phenology, development, and growth Micromorphology and agronomy Physiological and morphological responses to stress Crop modeling The value of long-term experiments

Corn

Corn PDF Author: C. Wayne Smith
Publisher: John Wiley & Sons
ISBN: 9780471411840
Category : Technology & Engineering
Languages : en
Pages : 984

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Book Description
Your all-in-one guide to corn. This book provides practical advice on planting techniques and rates, seed production, treating plant diseases, insect infestation and weeds, harvesting, processing, and worldwide utilization. This is the fourth, and final, volume in the series of comprehensive references on the major crops of the world. Covers new biotechnology techniques for plant breeding and pest management Provides practical advice on planting techniques and rates, seed production, treating plant diseases, insect infestation and weeds, harvesting, processing and worldwide utilization.

Cereal Research Communications

Cereal Research Communications PDF Author:
Publisher:
ISBN:
Category : Grain
Languages : en
Pages : 874

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The Maize Genome

The Maize Genome PDF Author: Jeffrey Bennetzen
Publisher: Springer
ISBN: 3319974270
Category : Science
Languages : en
Pages : 390

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Book Description
This book discusses advances in our understanding of the structure and function of the maize genome since publication of the original B73 reference genome in 2009, and the progress in translating this knowledge into basic biology and trait improvement. Maize is an extremely important crop, providing a large proportion of the world’s human caloric intake and animal feed, and serving as a model species for basic and applied research. The exceptionally high level of genetic diversity within maize presents opportunities and challenges in all aspects of maize genetics, from sequencing and genotyping to linking genotypes to phenotypes. Topics covered in this timely book range from (i) genome sequencing and genotyping techniques, (ii) genome features such as centromeres and epigenetic regulation, (iii) tools and resources available for trait genomics, to (iv) applications of allele mining and genomics-assisted breeding. This book is a valuable resource for researchers and students interested in maize genetics and genomics.