Download or read book Introgression for Exotic Maize Germplasm Followed by Selection for Stalk Quality and Grain Yield written by Bruno Albrecht and published by . This book was released on 1986 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introgression of Exotic Germplasm for Improving Maize Zea Mays L Breeding Populations written by Jose L. Crossa-Hiriart and published by . This book was released on 1984 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ninety S1 families from three populations representing three levels (0%, 25% and 50%) of introgression of exotic maize germplasm into an adapted population were developed and evaluated at two locations. A theoretical approach to the problem of finding an intensity os selection and effective population size which maximizes the final chance of fixation of favorable alleles in different foundation stocks was examined. The S1 families from the cross yielded significantly less than those from adapted and backcross populations. Adapted and backcross populations yielded similarly. This suggests that major genes for lack of adaptation are acting in the crosses population. A significant quadratic relationships between S1 family means and proportion of adapted materialin the foundation stock for grain yield indicate that a second backcross to the adapted population would not produce a significant increase in grain yield. Greater genetic variance and predicted gain from selection in the population cross compared to the adapted and backcross population indicate possible benefits from the use of exotic germplasm in long-term selection programs. The choice of using one or two generations of backcrossing to the adapted population does not seem to be useful when, for a given locus, Ps (frequency of favorable allele in adapted population) is low and P2 (frequency of favorabel allele in exotic population) takes values larger than .5.5 While the N (effective population size) in cross population, that makes the final (...).
Download or read book Leveraging Genetic Diversity in Maize Breeding written by Alden Perkins and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Maize (Zea mays L.) cultivars grown in the United States are not closely related to cultivars found in many other parts of the world, and pedigree records suggest that there has been little use of germplasm from other countries in US maize breeding. Exotic germplasm could be a useful source of alleles for improving traits such as grain quality, disease resistance, and abiotic stress tolerance in US populations. Exotic cultivars may also contain alleles that confer adaptation to different climate conditions and management practices, however, which could be detrimental in US growing environments. This dissertation contains a review article about the importance of genetic diversity in breeding and three research projects that involve the incorporation of exotic diversity into US maize germplasm. In the first research project, we investigated the effects of introgressions from open-pollinated populations that originated in Latin America on the performance of maize hybrids in US environments. We compared the phenotypic stability of exotic-derived hybrids and US-adapted hybrids, and we found that the two groups had significantly different stability values for grain yield and flowering time. In the second project, we estimated the effects of exotic introgressions contained in maize populations created by a public-private partnership on grain protein content, kernel vitreousness, and other agronomic traits. One introgression was estimated to increase grain protein content by 0.78%, although it was also associated with detrimental changes in the time of flowering and plant height. Finally, we compared models that could be used to predict the phenotypes of untested hybrids in diverse populations, which could make the process of incorporating new diversity into US germplasm more efficient. We found that models using near-infrared absorbance data collected on inbred seeds as predictors were inferior to models based on genotypic data in most cases, although the difference between the methods was small for traits such as grain moisture and test weight. An alternative to the standard genomic best linear unbiased prediction (GBLUP) method that included additional regularization, called the sparse selection index method, was superior to GBLUP models when large training populations were available. Collectively, the results from these projects provide new insights into how exotic germplasm can be used in US maize breeding most effectively.
Download or read book Conversion of Elite Subtropical Maize Germplasm to Temperate Environments written by Homer Gene Caton and published by . This book was released on 1999 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semi-exotic BC1F1 testcrosses were evaluated in five Iowa environments during 1998, with average grain yields of 95.7 q ha7−1 (153.1 bu ac−1). Selected testcrosses had grain yields similar to or greater (p[Less than or equal to]0.05) than their checks. Grain moisture of selected LSC-exotic and RYD-exotic testerosses was similar to and greater, respectively, than the recurrent parent testerosses, and resistance to root and stalk lodging was similar to the checks. Results support backcross introgression to incorporate alleles from exotic sources, to maintain the agronomic traits of the recurrent parent, and to maintain or enhance the combining ability of the recurrent parent heterotic pool. Inbred lines developed in CIMMYT's hybrid program have been improved for agronomic traits, for tolerance to inbreeding, and heterotic alignment. Pre-selected exotic germplasm represents a valuable resource for widening the genetic base of temperate maize.
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 Plant Breeding Abstracts written by and published by . This book was released on 1997 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research Progress at the Illinois Agricultural Experiment Station written by and published by . This book was released on 1980 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2002 with total page 854 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Distant Hybridization of Crop Plants written by G. Kalloo and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wild taxa are invaluable sources of resistance to diseases, insects/ pests, nematodes, temperature extremes, salinity and alkalinity stresses, and also of nutritional quality; adaptation; genetic diversity and new species. Utilization of wild relatives of a crop depends largely upon its crossability relations with cultivated varieties. Sev eral wild species are not crossable with the commercial cultivars due to various isolation barriers. Furthermore, in a few cases, hybridiza tion is possible only in one direction and reciprocal crosses are not successful, thus depriving the utilization of desired cytoplasm of many species. However, techniques have been developed to over come many barriers and hybrid plants are produced. New crop species have been developed by overcoming the F 1 sterility and producing amphidiploids and such crops are commercially being grown in the field. The segregation pattern ofF 1 hybrids produced by distant hybridization in segregating generations are different from the intervarietal hybrids. In former cases, generally, unidirectional segregation takes place in early generations and accordingly, selec tion procedures are adopted. In most of the cases, backcross or modified backcross methods have been followed to utilize wild species, and thus numerous types of resistance and other economical attributes have been transferred in the recurrent parents. Protoplast fusion has been amply demonstrated in a number of cases where sexual hybridization was not possible and, as a result, hybrids have been produced.
Download or read book Index to American Doctoral Dissertations written by and published by . This book was released on 1986 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crop Wild Relatives and Climate Change written by Robert J. Redden and published by John Wiley & Sons. This book was released on 2015-08-17 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two major challenges to continued global food security are the ever increasing demand for food products, and the unprecedented abiotic stresses that crops face due to climate change.Wild relatives of domesticated crops serve as a reservoir of genetic material, with the potential to be used to develop new, improved varieties of crops. Crop Wild Relative and Climate Change integrates crop evolution, breeding technologies and biotechnologies, improved practices and sustainable approaches while exploring the role wild relatives could play in increasing agricultural output. Crop Wild Relative and Climate Change begins with overviews of the impacts of climate change on growing environments and the challenges that agricultural production face in coming years and decades. Chapters then explore crop evolution and the potential for crop wild relatives to contribute novel genetic resources to the breeding of more resilient and productive crops. Breeding technologies and biotechnological advances that are being used to incorporate key genetic traits of wild relatives into crop varieties are also covered. There is also a valuable discussion on the importance of conserving genetic resources to ensure continued successful crop production. A timely resource, Crop Wild Relative and Climate Change will be an invaluable resource for the crop science community for years to come.
Download or read book Broadening the Genetic Base of Crop Production written by H. David Cooper and published by . This book was released on 2001 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the previously neglected interface between the conservation of plant genetic resources and their utilization. Only through utilization can the potential value of conserved genetic resources be realized. However, as this book shows, much conserved germplasm has to be subjected to long-term pre-breeding and genetic enhancement before it can be used in plant breeding programs.The authors explore the rationale and approaches for such pre-breeding efforts as the basis for broadening the genetic bases of crop production. Examples from a range of major food crops are presented and issues analyzed by leading authorities from around the world.
Download or read book Specialty Corns written by Arnel R. Hallauer and published by CRC Press. This book was released on 2000-08-23 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Completely revised and updated, the Second Edition of Specialty Corns includes everything in the first edition and more. Considered the standard in this field, significant changes have been made to keep all the information current and bring the references up-to-date. Two new chapters have been added to keep up with the latest trends: Blue Corn and
Download or read book Genomics of Plant Genetic Resources written by Roberto Tuberosa and published by Springer Science & Business Media. This book was released on 2013-11-08 with total page 711 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our lives and well being intimately depend on the exploitation of the plant genetic resources available to our breeding programs. Therefore, more extensive exploration and effective exploitation of plant genetic resources are essential prerequisites for the release of improved cultivars. Accordingly, the remarkable progress in genomics approaches and more recently in sequencing and bioinformatics offers unprecedented opportunities for mining germplasm collections, mapping and cloning loci of interest, identifying novel alleles and deploying them for breeding purposes. This book collects 48 highly interdisciplinary articles describing how genomics improves our capacity to characterize and harness natural and artificially induced variation in order to boost crop productivity and provide consumers with high-quality food. This book will be an invaluable reference for all those interested in managing, mining and harnessing the genetic richness of plant genetic resources.
Download or read book Quality Breeding in Field Crops written by Asif M. Iqbal Qureshi and published by Springer. This book was released on 2019-02-15 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Development of superior crops that have consistent performance in quality and in quantity has not received the same emphasis in the field of genetics and breeding as merited. Specialty trait requires special focus to propagate. Yet basic germplasm and breeding methodologies optimized to improve crops are often applied in the development of improved specialty types. However, because of the standards required for specialty traits, methods of development and improvement are usually more complex than those for common commodity crops. The same standards of performance are desired, but the genetics of the specialty traits often impose breeding criteria distinct from those of non-specialty possessing crops. Specifically, quality improvement programs have unique characteristics that require careful handling and monitoring during their development for specific needs. Adding value either via alternative products from the large volumes of grain produced or development of specialty types is of interest to producers and processors. This work assimilates the most topical results about quality improvement with contemporary plant breeding approaches.The objective of this book is to provide a summary of the germplasm, methods of development, and specific problems involved for quality breeding. In total, fourteen chapters, written by leading scientists involved in crop improvement research, provide comprehensive coverage of the major factors impacting specialty crop improvement.
Download or read book Races of Maize in Mexico written by Edwin John Wellhausen and published by . This book was released on 1952 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: History of maize classification. How races used in classification. Geographical distribution. Existing races of maize in Mexico.
Download or read book Drought Stress in Maize Zea mays L written by Muhammad Aslam and published by Springer. This book was released on 2015-11-20 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on early germination, one of maize germplasm most important strategies for adapting to drought-induced stress. Some genotypes have the ability to adapt by either reducing water losses or by increasing water uptake. Drought tolerance is also an adaptive strategy that enables crop plants to maintain their normal physiological processes and deliver higher economical yield despite drought stress. Several processes are involved in conferring drought tolerance in maize: the accumulation of osmolytes or antioxidants, plant growth regulators, stress proteins and water channel proteins, transcription factors and signal transduction pathways. Drought is one of the most detrimental forms of abiotic stress around the world and seriously limits the productivity of agricultural crops. Maize, one of the leading cereal crops in the world, is sensitive to drought stress. Maize harvests are affected by drought stress at different growth stages in different regions. Numerous events in the life of maize crops can be affected by drought stress: germination potential, seedling growth, seedling stand establishment, overall growth and development, pollen and silk development, anthesis silking interval, pollination, and embryo, endosperm and kernel development. Though every maize genotype has the ability to avoid or withstand drought stress, there is a concrete need to improve the level of adaptability to drought stress to address the global issue of food security. The most common biological strategies for improving drought stress resistance include screening available maize germplasm for drought tolerance, conventional breeding strategies, and marker-assisted and genomic-assisted breeding and development of transgenic maize. As a comprehensive understanding of the effects of drought stress, adaptive strategies and potential breeding tools is the prerequisite for any sound breeding plan, this brief addresses these aspects.
