Origin of Cultivated RiceBy
- H.-I. Oka
This book aims to up-date our present understanding of the origin of cultivated rice and in doing so involves different disciplines of biology and the archaeological-historical sciences. Various recent discoveries are reviewed and questions posed for further consideration by the reader.The book covers a wide range of studies on problems relative to the origin of cultivated rice, placing emphasis on ecological and genetical aspects. Comparisons are made between two cultivated rice species, independently evolved in Asia and Africa from respective wild progenitors. Phenomena are observed during mixed planting and hybrids discussed. Detailed information is presented about Asian common wild rice, thought to be the ancestor of common rice. The dynamics of domestication are considered with regard to hybridization, selection, formation of weedy types and the accumulation of genetic diversity. Also included are recent archaeological findings in relation to the beginnings of rice culture, leading to the hypothesis of diffused origins. Cultivars of common rice fall into one of two types called Indica and Japonica. The dynamics of differentiation are discussed, giving evidence and different hypotheses. Information on the genetic bases and functions of various reproductive barriers found between the cultivated and wild taxa is presented and discussed. The practical aspects of crop-evolutionary studies concerned with the breeding phylosophy and germplasm conservation are briefly commented on and arguments for rediversification of crop germplasm and conservation of the environment given.Senior scientists and post-graduate students interested in rice genetics, crop evolution, and related sciences will find this book invaluable.
Developments in Crop Science
Published: January 1988
- Synopsis. 1. The genus Oryza. Enumeration of species. Genome analysis. Confusion in species names. Habitats of wild Oryza species. Numerical taxonomy. Two cultivated rice species. 2. The ancestors of cultivated rice. Classical literature. Evaluation of relationships between taxa. Determination of the ancestral species of cultivated rice. Attempts to delimit the wild progenitor of O. sativa. 3. Ecology and population biology of common wild rice. Distribution and habitats. Variations in breeding systems. Adaptive strategies. Regenerating success. 4. Genetic variations and evolutionary dynamics. Variations between and within taxa of wild rices. Genetic structure of wild-rice populations. Evidence for within-population differentiation in adaptive strategy. Association between isozyme markers and fitness characters. 5. The dynamics of domestication. Characteristics of domesticated plants. Hybridization. Selection. Weedy forms of rice. Genetic diversity in land races of rice. Geographical distribution of genetic diversity. 6. The homeland of Oryza sativa. Origin of agriculture. Archaeology and history in relation to the origin of rice. Questions about the origin of O. sativa. 7. Indica-Japonica differentiation of rice cultivars. Classification of varieties into groups. Differences between Indica and Japonica types. Intervarietal hybrid sterility. Dynamics of Indica-Japonica differentiation. Putative internal mechanisms of differentiation. 8. Functions and genetic bases of reproductive barriers. Reproductive barriers found in cultivated rice and their wild relatives. Analysis of genetic bases of hybrid sterility. Cytoplasmic-genic male sterility. Hybrids between O. sativa and O. glaberrima. Introgression across isolating barriers. 9. Variations in adaptability of environment. Photoperiodic response. Adaptation to upland and deepwater conditions. Fertilizer response. General and specific adaptabilities. Rediversification for better adaptability. 10. Germplasm conservation. Background. Collection from the field. Preservation of population samples. References. Subject index.