Dangerous Liaisons?


Book Description

With the advent of genetic engineering, "designer" crops might interbreed with natural populations. Could such romances lead to the evolution of "superweeds", as some have suggested? But haven't crops had sex with wild plants in the past? Has such gene swapping occurred without consequences? And if consequences have indeed occurred, what lessons can be gleaned for engineered crops? In Dangerous Liaisons? Norman Ellstrand examines these and other questions. He begins with basic information about the natural hybridization process. He then describes what we now know about hybridization between the world's most important crops—such as wheat, rice, maize, and soybeans—and their wild relatives. Such hybridization, Ellstrand explains, is not rare, and has occasionally had a substantial impact. In some cases, the result was problematic weeds. In others, crop genes have diluted natural diversity to the point that wild populations of certain rare species were absorbed into the gene pool of the more common crop, essentially bringing the wild species to the brink of extinction. Ellstrand concludes with a look to the future. Will engineered crops pose a greater threat than traditional crops? If so, can gene flow and hybridization be managed to control the escape of engineered genes? This book will appeal to academics, policy makers, students, and all with an interest in environmental issues.




Gene Flow Between Crops and Their Wild Relatives


Book Description

Reviewing the relevant scientific and technical literature, this work summarizes the current state-of-the-art knowledge related to gene flow and introgression (the permanent incorporation of genetic information from one set of differentiated populations into another) between genetically modified crops and their wild relatives. They analyze the biological framework for protecting the genetic integrity of indigenous wild relatives of crops in centers of crop origin and diversity, focusing on the issues of emission, dispersal, and deposition of pollen and/or seed; the likelihood and extent of gene flow from crops to wild relatives; and stabilization and the spread of traits in wild species. The material is organized into crop chapters, each of which covers general biological information of the crop; the most important crop wild relatives together with information about their ploidy levels, diverse genomes, centers of origin, and geographic distribution; the crop's potential for hybridization with its wild relatives; pollen flow studies related to pollen dispersal distances and hybridization rates; the current state of the genetic modification technology regarding that crop; and research gaps. The crop chapters discuss banana and plantain; barley; canola and oilseed rape; cassava, manioc, and yucca; chickpea; common bean; cotton; cowpea; finger millet; maize and corn; oat; peanut and groundnut; pearl millet; pigeonpea; potato; rice; sorghum; soybean; sweet potato, batata, and camote; and wheat and bread wheat.




Introgression from Genetically Modified Plants Into Wild Relatives


Book Description

Introgression is the incorporation of a gene from one organism complex into another as a result of hybridization. A major concern with the use of genetically modified plants is the unintentional spread of the new genes from cultivated plants to their wild relatives and the subsequent impacts on the ecology of wild plants and their associated flora and fauna.The book reviews these issues, focusing on the ecological and evolutionary effects of introducing GM cultivars. It presents current knowledge of crop-wild relatives hybridization and introgression, and the measurement and prediction of their consequences. As a result it represents a major contribution to the debate about the risks of GM crops and measures, such as post commercialisation monitoring, required to determine the longer term impacts of GM crops on ecosystems.The book presents edited and revised presentations given at a conference of the same name, organised in January 2003 by the University of Amsterdam (Netherlands) and the Robert Koch Institute (Germany), on behalf of the European Science Foundation funded program for Assessment of the Impacts of Genetically Modified Plants (AIGM ).




Safety of Genetically Engineered Foods


Book Description

Assists policymakers in evaluating the appropriate scientific methods for detecting unintended changes in food and assessing the potential for adverse health effects from genetically modified products. In this book, the committee recommended that greater scrutiny should be given to foods containing new compounds or unusual amounts of naturally occurring substances, regardless of the method used to create them. The book offers a framework to guide federal agencies in selecting the route of safety assessment. It identifies and recommends several pre- and post-market approaches to guide the assessment of unintended compositional changes that could result from genetically modified foods and research avenues to fill the knowledge gaps.




Herbicide-Resistant Crops


Book Description

Edited by a recognized leader in the field, Herbicide-Resistant Crops is the first book to cover all of the issues related to the controversial topic of herbicide-resistant crops. It provides extensive discussions of the modern biotechnological methods that have been used to develop such crops, and reviews the implications - both positive and negative - of developing crops that are resistant to herbicides. The creation and anticipated applications of specific herbicide-resistant crops are also discussed. In addition, the book covers the potential impact of herbicide-resistant crops on weed management practices and the environment, and presents issues related to the regulation and economics of these crops. The editor has brought together a diverse group of professionals, representing the several distinct areas impacted by the new technology of herbicide-resistant crops. The wide range of viewpoints presented in this book creates a balanced and complete survey, providing a notable contribution to the literature.




Distant Hybridization of Crop Plants


Book Description

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.




Hybrid Zones and the Evolutionary Process


Book Description

Hybrid zones--geographical areas in which the hybrids of two races are found--have attracted the attention of evolutionary biologists for many years, both because they are windows on the evolutionary process and because the patterns of animals and plant variation seen in hybrid zones do notfit the traditional classification schemes of taxonomists. Hybrid zones provide insights into the nature of the species, the way barriers to gene exchange function, the genetic basis of those barriers, the dynamics of the speciation process. Hybrid Zones and the Evolutionary Process synthesizes theextensive research literature in this field and points to new directions in research. It will be read with interest by evolutionary biologists, geneticists, and biogeographers.




Crop Wild Relative Conservation and Use


Book Description

Crop wild relatives (CWR) are species closely related to crop plants which can contribute beneficial traits such as pest or disease resistance and yield improvement. Through an examination of national, regional and global context of CWR, this text presents methodologies and case studies that provide recommendations for global conservation and use.




Principles of Crop Improvement


Book Description




Genetically Engineered Crops


Book Description

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.