Download or read book Genotype X Environment Interaction Yield Stability and Adaption Responses of 25 Single cross Maize Zea Mays L Hybrids Grown in Michigan written by Kingstone Mashingaidze and published by . This book was released on 1987 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1987 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stability Analysis of Single cross Hybrids of Maize Zea Mays L written by Jean Barbara Cormack and published by . This book was released on 1997 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Yield data from three experiments of maize single cross trials grown at 5 to 8 locations in 1994, 1995, and 1996 were analyzed for stability using regression methods. Only single crosses grown in all locations and years (environments) were included in the analyses. Effects for environments, genotypes, genotype x environment, heterogeneity of regression (slopes), and deviations from regression were tested for significance. Slopes and deviation from regression were calculated for each single cross and slopes were tested for equality to 0.0 and 1.0. Slopes sums of squares were subdivided into sums of squares due to concurrence and non-concurrence. Subsets of each experiment were also analyzed to examine whether stability changed in environments stratified by mean yield levels or by years. The analysis of one experiment revealed significant differences among single cross slopes and non-concurrence. The other two experiments were unusual in that the tests for heterogeneity of slopes were not significant.
Download or read book Genotype X Environment Interaction and Stability in Maize Zee Mays L Hybrids with CD Copy written by Shailendra Dadhich and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Index to American Doctoral Dissertations written by and published by . This book was released on 1989 with total page 1252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Genotype X Environment Interaction and Stability Parameters for Yield and Other Agronomic Traits Among Maize Zea Mays L Composites in Nepal written by Kaushal Kishore Lal and published by . This book was released on 1984 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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
Download or read book Yield Stability Analysis of Maize in Ethiopia written by Zerihun Tadesse and published by . This book was released on 2012-09-24 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physiological Determinants of Nitrogen Dynamics in Response to Genotype by Management Interactions in US Maize Hybrids written by Javier Antonio Fernandez and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In maize (Zea mays L.), the largest staple crop in the world, nitrogen (N) represents a major limiting factor for productivity. However, improving N use efficiency (NUE) is still one of the most critical research issues to achieve food security in a context affected by climate change. This dissertation is structured in six chapters (Chapter 1, Introduction, and Chapter 6, Conclusions) outlining the agronomic and physiological traits associated with a better N utilization in US maize hybrids across Genotype x Environment x Management (G x E x M) conditions, with emphasis on the implications of long-term genetic selection. Chapter 2 presents a comprehensive meta-analysis on a diverse dataset assembled from field studies from 1983 until 2018 to compare early- versus late-season N (applied after tenth-leaf) fertilization effects on yield and N recovery efficiency. Results provided evidence for the lack of a main effect of late N application on yields but suggest the existence of crop growth conditions prone to a greater reproductive N uptake where this practice might be suitable. Throughout multiple field trials, Chapter 3-5 advanced in our understanding of how long-term genetic improvement has modified N dynamics across G x M scenarios. Chapter 3 proposes a novel N by carbon (C) framework to analyze and define key morpho-physiological traits of breeding interest that allow modern maize plants to achieve higher productivity and NUE. Results show both an earlier stem N remobilization and a decline in grain N concentration are key drivers of N utilization efficiency in modern hybrids. Chapter 4 documents the underlying fluxes of post-flowering N allocation and translocation dynamics behind genetic improvement over time in field-grown corn. This research suggests that direct selection for yield has indirectly favored N allocation to leaves in modern genotypes resulting in an improved post-flowering C accumulation. Finally, Chapter 5 explores historical changes in the contribution of grain weight and its physiological characteristics to maize genetic progress. This research evidences a significant contribution of increments in grain weight in US maize but concludes the trade-off between grain number and weight poses a challenge for future yield progress.
Download or read book Genotype by Environment Interaction and Yield Stability of Maize Hybrids Evaluated in Ethopia written by Abdurahman Beshir Issa and published by . This book was released on 2009 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1984 with total page 1086 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1973- include the following subject areas: Biological sciences, Agriculture, Chemistry, Environmental sciences, Health sciences, Engineering, Mathematics and statistics, Earth sciences, Physics, Education, Psychology, Sociology, Anthropology, History, Law & political science, Business & economics, Geography & regional planning, Language & literature, Fine arts, Library & information science, Mass communications, Music, Philosophy and Religion.
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.
Download or read book Genotype environment Interaction and Its Effects on Heterotic Patterns in a Diallel of Exotic and Local Maize Zea Mays L in Mid Altitude Zones of Kenya written by Omari Mumani Odongo and published by . This book was released on 1993 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Managing Global Genetic Resources written by National Research Council and published by National Academies Press. This book was released on 1993-02-01 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: This anchor volume to the series Managing Global Genetic Resources examines the structure that underlies efforts to preserve genetic material, including the worldwide network of genetic collections; the role of biotechnology; and a host of issues that surround management and use. Among the topics explored are in situ versus ex situ conservation, management of very large collections of genetic material, problems of quarantine, the controversy over ownership or copyright of genetic material, and more.
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.
Download or read book Comprehensive Dissertation Index Agriculture written by and published by . This book was released on 1984 with total page 1080 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Drought Resistance in Crops with Emphasis on Rice written by International Rice Research Institute and published by Int. Rice Res. Inst.. This book was released on 1982 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
