Multi-Location Evaluation of Agronomic Traits in Maize Hybrids

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (865 download)

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Book Synopsis Multi-Location Evaluation of Agronomic Traits in Maize Hybrids by : Michael Cody McKee

Download or read book Multi-Location Evaluation of Agronomic Traits in Maize Hybrids written by Michael Cody McKee and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Maize (Zea mays L.) is one of the main crops grown in the United States. Genetic improvement over the last century has seen a shift from using open-pollinated varieties to single cross hybrids. This has resulted in major grain yield gains and improved management methodologies. However, there is still concern about reduced genetic diversity in elite corn germplasm and the potential effects this could have on future maize productivity in the presence of numerous abiotic and biotic pressures. One solution to this issue is the incorporation of exotic germplasm into existing maize improvement programs. This exotic material must be evaluated and characterized because too much or poorly matched exotic material can lead to reduced productivity. The use of multiple environments representative to the target improvement area is the best way to determine the true potential of certain material. The objectives of this research were to: i) estimate the responses of hybrids to aflatoxin and their agronomic performance across a range of environments under inoculation with Aspergillus flavus; ii) identify the hybrids within each group that exhibit the lowest levels of contamination; iii) analyze the relationship between agronomic performance and aflatoxin accumulation; and iv) determine how Genotype x Environment interactions affect these traits. Agronomic data was collected in ten Texas environments in 2005 for hybrids created from yellow, white, and Quality Protein Maize material that was crossed with one of two elite temperate inbred testers, LH195 or LH210. Response to aflatoxin was measured in eight of these environments. U.S. commercial hybrids were used as checks. Significant differences between hybrids were observed at different environments for different traits. Overall the experimental hybrids had lower aflatoxin accumulation than the commercial checks. They also yielded lower and had lower test weights and 1000 kernel weights. However, there were some hybrids that were competitive with the commercial checks for these agronomic traits. The incorporation of this material into established U.S. lines could be beneficial with regards to aflatoxin accumulation and kernel quality, which could ultimately translate to higher yields and crop quality. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/148414

GGE Biplot Analysis

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Publisher : CRC Press
ISBN 13 : 1420040375
Total Pages : 287 pages
Book Rating : 4.4/5 (2 download)

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Book Synopsis GGE Biplot Analysis by : Weikai Yan

Download or read book GGE Biplot Analysis written by Weikai Yan and published by CRC Press. This book was released on 2002-08-28 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research data is expensive and precious, yet it is seldom fully utilized due to our ability of comprehension. Graphical display is desirable, if not absolutely necessary, for fully understanding large data sets with complex interconnectedness and interactions. The newly developed GGE biplot methodology is a superior approach to the graphical analys

Developing Drought and Low N-tolerant Maize

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Publisher : CIMMYT
ISBN 13 : 9789686923933
Total Pages : 580 pages
Book Rating : 4.9/5 (239 download)

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Book Synopsis Developing Drought and Low N-tolerant Maize by : G. O. Edmeades

Download or read book Developing Drought and Low N-tolerant Maize written by G. O. Edmeades and published by CIMMYT. This book was released on 1996 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Evaluation of Genetic Gain for Dynamic Leaf Traits in Maize Using Field Spectroscopy

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ISBN 13 :
Total Pages : 106 pages
Book Rating : 4.:/5 (958 download)

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Book Synopsis Evaluation of Genetic Gain for Dynamic Leaf Traits in Maize Using Field Spectroscopy by : Jonathan Paul Luetchens

Download or read book Evaluation of Genetic Gain for Dynamic Leaf Traits in Maize Using Field Spectroscopy written by Jonathan Paul Luetchens and published by . This book was released on 2015 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapid introduction of cheap and precise genotyping technology has created a void between genotypes and phenotypes in maize breeding. While detailed genetic information is easily accessible, the data are lacking robust phenotypes to be used in mapping studies like genome-wide association. As a result, high-throughput phenotyping tools are necessary to rigorously characterize specific traits. In this study, agronomic traits and an active spectrometer system were used to monitor 36 era hybrids – popular commercial maize hybrids grown from 1936 to 2012 – to discover how various traits have changed over time. In conjunction with increased grain yield of 76 kg/ha per year, modern hybrids displayed a decreased anthesis silking interval, as well as decreased stalk lodging, root lodging, plant height, ear height, and early vegetative biomass, and increased staygreen. In addition, modern hybrids displayed increased leaf chlorophyll and water contents. The 760/730 vegetation index, designed to study plant health and nitrogen uptake using the red edge region of the electromagnetic spectrum, correlated strongly to total leaf chlorophyll content (R2 = 0.64) and also displayed higher values in modern hybrids at numerous points throughout the growing season. By understanding these morphological and physiological trends of maize hybrids over time, breeders can continue to select for traits that are known to enhance yield. Moreover, this research shows that high-throughput phenotyping tools that estimate chlorophyll content can be implemented into a breeding program because the technology can detect superior cultivars.

Genetics and Exploitation of Heterosis in Crops

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Publisher :
ISBN 13 : 9780891185499
Total Pages : 0 pages
Book Rating : 4.1/5 (854 download)

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Book Synopsis Genetics and Exploitation of Heterosis in Crops by : J. G. Coors

Download or read book Genetics and Exploitation of Heterosis in Crops written by J. G. Coors and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explore the momentous contributions of hybrid crop varieties with worldwide experts. Topics include an overview, quantitative genetics, genetic diversity, biochemistry and molecular biology, methodologies, commercial strategies, and examples from numerous crops.

Genotype X Environment Interactions

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Publisher : Food & Agriculture Org.
ISBN 13 : 9789251048702
Total Pages : 136 pages
Book Rating : 4.0/5 (487 download)

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Book Synopsis Genotype X Environment Interactions by : Paolo Annicchiarico

Download or read book Genotype X Environment Interactions written by Paolo Annicchiarico and published by Food & Agriculture Org.. This book was released on 2002 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: The projected increase in world population levels and the subsequent rise in food demand represents a huge challenge for agricultural production systems worldwide. This publication examines the opportunities and challenges raised by the use of plant genetic resources and highlights the contribution that data from multi-environment yield trials can provide for the definition of adaptation strategies and yield stability targets in plant breeding programmes. It contains a case study about a durum wheat crop programme in Algeria, and also includes a CD-ROM with data from IRRISTAT, a programme developed by the International Rice Research Institute (IRRI).

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

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ISBN 13 :
Total Pages : 166 pages
Book Rating : 4.:/5 (12 download)

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Book Synopsis Evaluation of Teosinte Genetic Diversity for Agronomic and Domestication Traits in Maize by : Avinash Karn

Download or read book Evaluation of Teosinte Genetic Diversity for Agronomic and Domestication Traits in Maize written by Avinash Karn and published by . This book was released on 2017 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Genetically Engineered Crops

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Publisher : National Academies Press
ISBN 13 : 0309437385
Total Pages : 607 pages
Book Rating : 4.3/5 (94 download)

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Book Synopsis Genetically Engineered Crops by : National Academies of Sciences, Engineering, and Medicine

Download or read book Genetically Engineered Crops written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2017-01-28 with total page 607 pages. Available in PDF, EPUB and Kindle. Book excerpt: Genetically engineered (GE) crops were first introduced commercially in the 1990s. After two decades of production, some groups and individuals remain critical of the technology based on their concerns about possible adverse effects on human health, the environment, and ethical considerations. At the same time, others are concerned that the technology is not reaching its potential to improve human health and the environment because of stringent regulations and reduced public funding to develop products offering more benefits to society. While the debate about these and other questions related to the genetic engineering techniques of the first 20 years goes on, emerging genetic-engineering technologies are adding new complexities to the conversation. Genetically Engineered Crops builds on previous related Academies reports published between 1987 and 2010 by undertaking a retrospective examination of the purported positive and adverse effects of GE crops and to anticipate what emerging genetic-engineering technologies hold for the future. This report indicates where there are uncertainties about the economic, agronomic, health, safety, or other impacts of GE crops and food, and makes recommendations to fill gaps in safety assessments, increase regulatory clarity, and improve innovations in and access to GE technology.

Quantitative Genetics in Maize Breeding

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Publisher : Springer Science & Business Media
ISBN 13 : 1441907661
Total Pages : 669 pages
Book Rating : 4.4/5 (419 download)

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Book Synopsis Quantitative Genetics in Maize Breeding by : Arnel R. Hallauer

Download or read book Quantitative Genetics in Maize Breeding written by Arnel R. Hallauer and published by Springer Science & Business Media. This book was released on 2010-09-28 with total page 669 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Genetic Combining Analysis of Food-grade Maize

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Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (819 download)

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Book Synopsis Genetic Combining Analysis of Food-grade Maize by : Adam Lyle Mahan

Download or read book Genetic Combining Analysis of Food-grade Maize written by Adam Lyle Mahan and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Maize genetic diversity includes an array of kernel colors (red, blue, purple) with blue concentrated in the aleurone and red primarily in the pericarp. Quality protein maize (QPM) is improved over normal maize in regards to grain concentration of the essential amino acids lysine and tryptophan but has not been widely adapted in part due to lower than conventional yields. These are minimally-utilized specialty corns when compared to the yellows and whites commonly grown. Red, blue, and purple pigments are antioxidant phytochemicals produced by the plant as secondary metabolites. Antioxidants have been linked to anti-cancer and other anti-inflammatory health benefits. QPM hybrids are desirable in developing countries where subsistent agriculture is commonly practiced and quality protein cereals are non-existent. These two diverse maize categories have been the subject of little breeding research compared to normal maize and the potential for high phenolic content as well as the characterization of these QPM hybrids has not been previously investigated. We evaluated 153 maize hybrids (84 colored, 69 QPM) across three locations. High heritability estimates were found for phenolic content (0.80), tryptophan (0.46), and endosperm opacity (0.82). It was encouraging that all three traits observed little genotype by environment (GxE) interaction across diverse environments. This proved the trait analysis procedure to be robust in detecting and separating genotypes for both total phenolic content in colored maize, and amino acids in QPM. Top combiners for phenolics were the purple maize "maize morado" and red lines, with blue, yellow and white maize performing in descending order. Within the tested hybrids, high per kernel antioxidants (measured by total phenolics) may be the answer for producing the most total phenolics, with the top hybrid yielding greater than twice the total phenolics as the top yielding yellow hybrid. The top QPM hybrid out yielded the top normal hybrid by 35 and 30% for lysine and tryptophan. Additionally, QPM endosperm opacity primarily followed an additive, mid-parent trend, with some hybrids (20%) from diverse germplasm backgrounds deviating from that trend displaying the complexity and recessive nature of multiple modifier loci. Additional agronomic and composition traits were minimally correlated with phenolics.

Grain Yield and Other Agronomic Characteristics of Selected Maize Hybrids Under Irrigation in Cyprus

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Publisher :
ISBN 13 :
Total Pages : 7 pages
Book Rating : 4.:/5 (668 download)

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Book Synopsis Grain Yield and Other Agronomic Characteristics of Selected Maize Hybrids Under Irrigation in Cyprus by : C. M. Josephides

Download or read book Grain Yield and Other Agronomic Characteristics of Selected Maize Hybrids Under Irrigation in Cyprus written by C. M. Josephides and published by . This book was released on 1990 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Plant Adaptation and Crop Improvement

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Publisher : IRRI
ISBN 13 : 0851991084
Total Pages : 650 pages
Book Rating : 4.8/5 (519 download)

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Book Synopsis Plant Adaptation and Crop Improvement by : Mark Cooper

Download or read book Plant Adaptation and Crop Improvement written by Mark Cooper and published by IRRI. This book was released on 1996 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of crop improvement; Analysis of genotype by environment interactions; Interpretation of genotype by environment interactions; Integrated approaches to plant improvement; Synthesis of strategies for crop improvement.

Evaluation of Low Phytic Acid Maize Germplasm Adapted to the Delmarva Peninsula

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Publisher :
ISBN 13 : 9781124479712
Total Pages : pages
Book Rating : 4.4/5 (797 download)

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Book Synopsis Evaluation of Low Phytic Acid Maize Germplasm Adapted to the Delmarva Peninsula by : Adrienne Kleintop

Download or read book Evaluation of Low Phytic Acid Maize Germplasm Adapted to the Delmarva Peninsula written by Adrienne Kleintop and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this project is to develop high yielding low phytic acid maize specifically adapted to the Delmarva Peninsula. The majority of the phosphorus in grain is in the chemical form of phytic acid. Phytic acid cannot be digested by monogastric animals such as poultry and swine. Consequently, most of the phytic acid is excreted into the environment posing a serious environmental threat to waterways. Breeding and commercialization of low phytic acid maize hybrids using the low phytic acid 1 (lpa1-1) trait could potentially alleviate the serious environmental and nutritional effects of phytic acid. However, in-depth evaluations on potential negative effects of lpa1-1 on yield and other agronomic traits are critical to determining the commercial feasibility of the trait. The objectives of this project aimed to (1) Determine the effects of lpa1 on the 100 kernel seed dry weight and starch, protein, and oil content (2) Evaluate the effect of lpa1 on yield, agronomic traits, and plant growth and development of near-isogenic inbred lines and hybrids over multiple years and locations and (3) Screen exotic germplasm collections for new sources of low phytic acid loci or alleles. The results suggest that the 100 kernel seed dry weight and kernel composition were unaffected by lpa1 and are unlikely to influence the yield. However, negative pleiotropic effects on the yield and plant growth and development were observed for lpa1/lpa1. Overall, the yield decrease between lpa1/lpa1 and +/+ ranged from 0.4 to 7.9% by hybrid. The yield decrease was more exaggerated under stressful weather conditions and the extent of the decrease varied by background. One particular hybrid was identified in which the yield decrease was minimized and is recommended for future breeding. It is theorized that the negative effects on yield result from the cumulative negative pleiotropic effects on vigor and development. Plants homozygous for lpa1 may exist in a weakened state and suffer more cellular damage as a result of the disruption of phytic acid's antioxidant function. Screening of exotic germplasm has identified one potential new low phytic acid source with the potential for future research.

Evaluation of Argentine Maize Hybrids and Exotic X Temperate Testcrosses Across Environments

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Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (759 download)

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Book Synopsis Evaluation of Argentine Maize Hybrids and Exotic X Temperate Testcrosses Across Environments by : Brett A. Ochs

Download or read book Evaluation of Argentine Maize Hybrids and Exotic X Temperate Testcrosses Across Environments written by Brett A. Ochs and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Maize (Zea mays L.) is grown in a wide range of environments and altitudes worldwide. Maize has transitioned from open pollinated varieties to single cross hybrids over the last century. While maize production and genetic gain has increased, genetic diversity among U.S. maize hybrids has narrowed. Problems, such as insect pressure, diseases, and mycotoxins, present obstacles for breeders. One approach is to use exotic germplasm in breeding programs to provide useful, novel alleles for productivity, grain quality, and disease resistance. Little exotic germplasm has been used, because of lack of agronomic adaptation and problems with lodging, earliness, and tall plants in more temperate areas. Using exotic elite materials and evaluating them in targeted regions might increase success. Objectives of this research were: to characterize and evaluate agronomic adaptation and performance of Argentine commercial hybrids in the U.S., to evaluate semi-exotic testcrosses developed from semi adapted 100% tropical lines and elite U.S. inbred LH195, and to estimate response to aflatoxin contamination of Argentine hybrids and semi-exotic testcrosses under inoculation with Aspergillus flavus. Agronomic data was collected during 2004 in eleven Texas environments for Argentine hybrids, and eight Texas environments for semi-exotic testcrosses. Response to aflatoxin was measured in three southern Texas environments. U.S. commercial hybrids were used as checks. Significant differences among hybrids were observed for most environments and traits. In general, Argentine hybrids yielded lower, had lower 1000 kernel weights, and greater test weights than U.S. hybrids. Hybrids AX889, AX882MG, and AX890MG were competitive with U.S. hybrids for grain yield and were stable across environments. Semi-exotic testcrosses had similar lodging and grain moisture percentages, heavier test weights and competitive grain yields compared with U.S. hybrids. Hybrid TX-LAMA2002-9-2-B/lH195 had the highest overall grain yield mean for semi-exotic testcrosses and yielded better than two U.S. hybrids. Argentine hybrids had lower aflatoxin concentration than U.S. hybrids; several hybrids had less than 50 ng g−1 aflatoxin. Semi-exotic testcrosses had reduced aflatoxin compared to U.S. hybrids, with several hybrids under 35 ng g−1. These elite, exotic materials show promise for breeding programs, with competitiveness for grain yield, kernel traits, and reduced aflatoxin levels.

Breeding for drought and nitrogen stress tolerance in maize: From theory to practice

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Author :
Publisher : CIMMYT
ISBN 13 : 9706480463
Total Pages : 69 pages
Book Rating : 4.7/5 (64 download)

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Book Synopsis Breeding for drought and nitrogen stress tolerance in maize: From theory to practice by : M. Bänzinger

Download or read book Breeding for drought and nitrogen stress tolerance in maize: From theory to practice written by M. Bänzinger and published by CIMMYT. This book was released on 2000 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction - why breed for drought and low N tolerance?; Conceptual framework - breeding; Conventional approaches to improving the drought and low N tolerance of maize; Conventional approaches challenged; The challenge of breeding for drought and low N tolerance; Maize under drought and low N stress; Conceptual framework - physiology; Water and the maize plant; Nitrogen and the maize plant; Maize under drought and low N stress - consequences for breeding; Stress management; Drought; Low N stress; Statistical designs and layout of experiments; Increasing the number of replicates; Improved statistical designs; Field layout; Border effects from alleys; Secondary traits; Why use secondary traits?; How do we decide on the value of secondary traits in a drought or low N breeding program?; Secondary traits that help to identify drought tolerance; Secondary traits that help to identify low N tolerance: Selection indices - Combining information on secondary traits with grain yield; Combining information from various experiments; Breeding strategies; Choice of germplasm; Breeding schemes; Biotechnology: potential and constraints for improving drought and low N tolerance; The role of the farmer in selection; What is farmer participatory research and why is it important?; What is new about farmer participatory research?; Participatory methodologies.

Study on the Comparative Performance of Various Hybrids and Composites for Yield and Other Agronomic Traits in Maize

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (652 download)

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Book Synopsis Study on the Comparative Performance of Various Hybrids and Composites for Yield and Other Agronomic Traits in Maize by : Shyam Sunder Pal

Download or read book Study on the Comparative Performance of Various Hybrids and Composites for Yield and Other Agronomic Traits in Maize written by Shyam Sunder Pal and published by . This book was released on 1969 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Maize Research

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Publisher : Nipa
ISBN 13 : 9788119215621
Total Pages : 0 pages
Book Rating : 4.2/5 (156 download)

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Book Synopsis Maize Research by : Jiban Shrestha

Download or read book Maize Research written by Jiban Shrestha and published by Nipa. This book was released on 2023-07-08 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book uates its readers about the methods and management of livestock during disasters. The book has covered all mad made and natural disasters and their effect on livestock and how they can be managed better for longer survival and help to the humans. Topics on how animals can sense a disaster in advance and what are the common indications given by them and how humans can benefit from it. Book elucidates the management of feeding, feed resources, production and health so as to make the livestock production economical. It is hoped that the compilation will prove useful for the researchers, planners and policy makers to understand the causes for the loss of productivity and health of livestock in drier regions and help in devising management plans towards sustenance and improvement of production.