When trying to solicit authors for this book it became apparent that the causal factors for heterosis at the physiological and biochemical level are today almost as obscure as they were 30 years ago. Though biometrical-genetical analyses point to dispersion of complementary genes - not overdominance - as the major cause of the phenomenon, plant breeders' experience still suggests a cautious, pragmatic approach to the dominance-overdominance controversy in breeding hybrid cultivars. Thus we are faced with a striking discordance between our limited comprehension of the causal factors and mechanism of heter osis on the one hand, and the extensive agricultural practice of utiliza tion of hybrid vigor on the other. Such utilization is the result of the economic value of hybrid combinations displaying superior yields and qualities as well as stability of performance, of benefits derived in breeding programs, and of the enhanced varietal protection of proprietary rights. No comprehensive and critical analysis of the phenomenon of heterosis in economic plants has been published for the last three decades since the now classical book Heterosis, edited by J . W. Gowen (Iowa State College Press, Ames, Iowa, 1952). The present book attempts to fill the gap and to assess the status of our present knowl edge of the concept, the basis, the extent, and the application of heterosis in economic plants."

view than its own proper males should fecundate each blossom." ANDREW KNIGHT Philosophical Transactions, 1799 Pollination mechanisms and reproduction have a decisive bearing upon rational procedures in plant breeding and crop production. This book intends to furnish' under one cover an integrated botanical, genetical and breeding-methodologi cal treatment of the reproductive biology of spermatophytes mainly angiosperms; it is based on an advanced topical course in plant breeding taught at the Hebrew University of Jerusa lem. We have tried to present a coverage which is concise, but as comprehensive as possible, of the pollination mechanism and modes of reproduction of higher plants, and to illustrate topics, whenever practicable, by examples from cultivated plants. Nevertheless, some relevant publications may have escaped our attention or may not be mentioned because of various limitations. The book is organized into three parts. The first part starts with an evaluation of the significance of the different pollination mechanisms for plant breeding and crop produc tion, describes modes of reproduction in higher plants and discusses ecology and dynamics of pollination. The second part is devoted to crops propagated by self pollination and describes specific breeding procedures for such crops. The third part details sexual reproduction in higher plants and handles three mechanisms involved in the prevention of self pollination and their utilization in plant breeding: sex expres sion, incompatibility, and male sterility."

The resolution of the sixty-year debate over continental drift, culminating in the triumph of plate tectonics, changed the very fabric of Earth science. This four-volume treatise on the continental drift controversy is the first complete history of the origin, debate and gradual acceptance of this revolutionary theory. Based on extensive interviews, archival papers and original works, Frankel weaves together the lives and work of the scientists involved, producing an accessible narrative for scientists and non-scientists alike. This second volume provides the first extensive account of the growing paleomagnetic case for continental drift in the 1950s and the development of apparent polar wander paths that showed how the continents had changed their positions relative to one another, more or less as Wegener had proposed. Paleomagnetism offered the first physical measure that continental drift had occurred and helped determine the changing latitudes of the continents through geologic time.

The resolution of the sixty-year debate over continental drift, culminating in the triumph of plate tectonics, changed the very fabric of Earth science. This four-volume treatise on the continental drift controversy is the first complete history of the origin, debate and gradual acceptance of this revolutionary theory. Based on extensive interviews, archival papers and original works, Frankel weaves together the lives and work of the scientists involved, producing an accessible narrative for scientists and non-scientists alike. This third volume describes the expansion of the land-based paleomagnetic case for drifting continents and recounts the golden age of marine geology and geophysics. Fuelled by the Cold War, US and British workers led the way in making discoveries and forming new hypotheses, especially about the origin of oceanic ridges. When first proposed, seafloor spreading was just one of several competing hypotheses about the evolution of ocean basins.

Resolution of the sixty year debate over continental drift, culminating in the triumph of plate tectonics, changed the very fabric of Earth science. This four-volume treatise on the continental drift controversy is the first complete history of the origin, debate and gradual acceptance of this revolutionary theory. Based on extensive interviews, archival papers and original works, Frankel weaves together the lives and work of the scientists involved, producing an accessible narrative for scientists and non-scientists alike. This first volume covers the period in the early 1900s when Wegener first pointed out that the Earth's major landmasses could be fitted together like a jigsaw and went on to propose that the continents had once been joined together in a single landmass, which he named Pangaea. It describes the reception of Wegener's theory as it splintered into sub-controversies and geoscientists became divided between the 'fixists' and 'mobilists'.

The resolution of the sixty-year debate over continental drift, culminating in the triumph of plate tectonics, changed the very fabric of Earth science. This four-volume treatise on the continental drift controversy is the first complete history of the origin, debate and gradual acceptance of this revolutionary theory. Based on extensive interviews, archival papers and original works, Frankel weaves together the lives and work of the scientists involved, producing an accessible narrative for scientists and non-scientists alike. This fourth volume explains the discoveries in the mid 1960s which led to the rapid acceptance of seafloor spreading theory and how the birth of plate tectonics followed soon after with the geometrification of geology. Although plate tectonics did not explain the cause or dynamic mechanism of drifting continents, it provided a convincing kinematic explanation that continues to inspire geodynamic research to the present day.

Children in precarious health present particular problems for healthcare professionals because of their intimate relation to their family, and because of the family's need to provide major long-term source of support and to be actively involved in the decisions about their children's care. This collection of cases and commentaries in pediatrics highlights the difficult ethical dilemmas that can arise during high-tech hospital care of children in precarious circumstances. It serves as a teaching tool for clinical ethics and as an introduction for medical students and residents. Clinical cases are described in detail by the physicians involved, who focus on the ethical issues arising during treatment. Each case is then commented on in detail by a philosopher or other bioethicist. It thus serves well as an introduction to contemporary clinical bioethics, but with a firm grounding in the practicalities of real-life pediatric care in the hospital setting.

The success of the agricultural policy adopted in 1965 has given India the hope of escaping from its circle of poverty. At the same time the increased rate of economic development seems to have exacerbated social tensions and accentuated disparities that may eventually undermine the foundations of rural political stability. Originally published in 1971. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

The resolution of the sixty-year debate over continental drift, culminating in the triumph of plate tectonics, changed the very fabric of Earth science. This four-volume treatise on the continental drift controversy is the first complete history of the origin, debate and gradual acceptance of this revolutionary theory. Based on extensive interviews, archival papers and original works, Frankel weaves together the lives and work of the scientists involved, producing an accessible narrative for scientists and non-scientists alike. This fourth volume explains the discoveries in the mid 1960s which led to the rapid acceptance of seafloor spreading theory and how the birth of plate tectonics followed soon after with the geometrification of geology. Although plate tectonics did not explain the cause or dynamic mechanism of drifting continents, it provided a convincing kinematic explanation that continues to inspire geodynamic research to the present day.

The success of the agricultural policy adopted in 1965 has given India the hope of escaping from its circle of poverty. At the same time the increased rate of economic development seems to have exacerbated social tensions and accentuated disparities that may eventually undermine the foundations of rural political stability. Originally published in 1971. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

Resolution of the sixty year debate over continental drift, culminating in the triumph of plate tectonics, changed the very fabric of Earth Science. This four -volume treatise on the continental drift controversy is the first complete history of the origin, debate and gradual acceptance of this revolutionary theory. Based on extensive interviews, archival papers and original works, Frankel weaves together the lives and work of the scientists involved, producing an accessible narrative for scientists and non-scientists alike. This first volume covers the period in the early 1900s when Wegener first pointed out that the Earth's major landmasses could be fitted together like a jigsaw and went on to propose that the continents had once been joined together in a single landmass, which he named Pangaea. It describes the reception of Wegener's theory as it splintered into sub-controversies and geoscientists became divided between the 'fixists' and 'mobilists'. Other volumes in this set: Volume 2: Paleomagnetism and Confirmation of Drift Volume 3: Introduction of Seafloor Spreading Volume 4: Evolution into Plate Tectonics 4 Volume Set

Resolution of the sixty year debate over continental drift, culminating in the triumph of plate tectonics, changed the very fabric of Earth Science. This four-volume treatise on the continental drift controversy is the first complete history of the origin, debate and gradual acceptance of this revolutionary theory. Based on extensive interviews, archival papers and original works, Frankel weaves together the lives and work of the scientists involved, producing an accessible narrative for scientists and non-scientists alike. This second volume provides the first extensive account of the growing paleomagnetic case for continental drift in the 1950s and the development of Apparent Polar Wander Paths that showed how the continents had changed their positions relative to one another more or less as Wegener had proposed. Paleomagnetism offered the first physical measure that continental drift had occurred and helped determine the changing latitudes of the continents through geologic time. Other volumes in this set: Volume 1: Wegener and the Early Debate Volume 3: Introduction of Seafloor Spreading Volume 4: Evolution into Plate Tectonics 4 Volume Set"

Resolution of the sixty year debate over continental drift, culminating in the triumph of plate tectonics, changed the very fabric of Earth Science. This four-volume treatise on the continental drift controversy is the first complete history of the origin, debate and gradual acceptance of this revolutionary theory. Based on extensive interviews, archival papers and original works, Frankel weaves together the lives and work of the scientists involved, producing an accessible narrative for scientists and non-scientists alike. This third volume describes the golden age of marine geology and geophysics. Fuelled by the Cold War, US and British workers led the way in making discoveries and forming new hypotheses, especially about the origin of oceanic ridges. Discovery of transform faults in the ocean crust and symmetric patterns of geomagnetic reversals either side of mid-oceanic ridges in the mid 1960s led to the rapid acceptance of seafloor spreading and the birth of plate tectonics. Other volumes in this set: Volume 1: Wegener and the Early Debate Volume 2: Paleomagnetism and Confirmation of Drift Volume 4: Evolution into Plate Tectonics 4 Volume Set