Rice and rice breeding; Development of high-yielding rice varieties; Rice varieties and area; Summary of area estimates.

In this major 1993 work, Lloyd Evans provides an integrated view of the domestication, adaptation and improvement of crop plants, bringing together genetic diversity, plant breeding, physiology and aspects of agronomy. Considerations of yield and maximum yield provide continuity throughout the book. Food, feed, fibre, fuel and pharmaceutical crops are all discussed. Cereals, grain legumes and root crops, both temperate and tropical, provide many of the examples, but pasture plants, oilseeds, leafy crops, fruit trees and others are also considered. After the introductory chapter, the increasing significance of crop yields to the world's food supply is highlighted. The next three chapters consider changes to crop plants over the last ten thousand years, including domestication, adaptation and improvement. Aimed at research workers and advanced students in crop physiology and ecology, agronomy and plant breeding, this book also reaches conclusions of relevance to those concerned with developmental policy, agricultural research and management, environmental quality, resource depletion and human history.

Topics for the Beltsville Symposia are selected to highlight specific areas of research and science policy that are of concern to scientists in the Beltsville Area as well as to the general scientific community. Each sympo sium in the series is structured to provide a realistic appraisal of current findings, research progress, and relevant policy issues within the constraints established by the organizing committee. Thus, the presentations and dis cussions that have marked these symposia have had a strong appeal to the broad community of scientists. Knowledge of the diversity of living organisms is still quite limited. Since the time of Linnaeus, about 1.7 million species have been described. The actual number has been estimated between 5-50 million. Many species, land races, and strains are vanishing. Clearly, the world's scientific institutions are inadequately equipped to attain sufficient knowledge of a significant fraction of the diverse living forms. Also, efforts in the collection and preservation of germplasm of plants and animals urgently need to be strengthened. These mattes are critically important to future generations. This symposium addresses vital concerns of biotic diversity and germ plasm preservation from diverse perspectives. Many of the parts provide concrete recommendations for action, and they call attention to areas of research that must be pursued with intensity.