Genetic diversity and conservation and utilization of plant genetic resources V. Ramanatha Rao∗ & Toby Hodgkin
Senior Scientist (Genetic Diversity/Conservation), IPGRI-APO, Serdang, Malaysia and Principal Scientist, GRST, IPGRI, Rome, Italy (∗ requests for offprints; E-mail: email@example.com) Received 3 January 2001; accepted in revised form 12 July 2001
Key words: adaptation, bottleneck, breeding systems, distribution, extent, genetic diversity, geographic variation, plant genetic resources, use
Abstract Biodiversity refers to variation within the living world, while genetic diversity represents the heritable variation within and between populations of organisms, and in the context of this paper, among plant species. This pool of genetic variation within an inter-mating population is the basis for selection as well as for plant improvement. Thus, conservation of this plant genetic diversity is essential for present and future human well-being. During recent years, there has been increasing awareness of the importance of adopting a holistic view of biodiversity, including agricultural biodiversity, conservation for sustainable utilization and development. These principles have been enshrined in the Convention on Biological Diversity and the Global Plan of Action of the Food and Agriculture Organization of the United Nations. The emphasis is now to understand the distribution and extent of genetic diversity available to humans in plant species, so that the genetic diversity can be safely conserved and efﬁciently used. It is generally recognized that plant genetic diversity changes in time and space. The extent and distribution of genetic diversity in a plant species depends on its evolution and breeding system, ecological and geographical factors, past bottlenecks, and often by many human factors. Much of the large amount of diversity of a species may be found within individual populations, or partitioned among a number of different populations. A better understanding of genetic diversity and its distribution is essential for its conservation and use. It will help us in determining what to conserve as well as where to conserve, and will improve our understanding of the taxonomy and origin and evolution of plant species of interest. Knowledge of both these topics is essential for collecting and use of any plant species and its wild relatives. In order to mange conserved germplasm better, there is also a need to understand the genetic diversity that is present in collections. This will help us to rationalize collections and develop and adopt better protocols for regeneration of germplasm seed. Through improved characterization and development of core collections based on genetic diversity information, it will be possible to exploit the available resources in more valuable ways.
Introduction Biological diversity may be deﬁned as the variation present in all species of plants and animals, their genetic material and the ecosystems in which they occur. Diversity can occur at three levels: genetic diversity (variation in genes and genotypes), species diversity (species richness) and ecosystem diversity (communities of species and their environment). The importance
of biodiversity for humankind has been well recognised in the recent decades and many would argue that diversity is essential for allowing sustainable development of various human activities. Biological diversity can enable social and economic systems to ﬂourish in ways that allow the poorest to meet their food and nutritional needs and retain the cultural diversity of countries throughout the world (Shiva, 1994). The biological resources of each country are important, but
2 not all countries are equally endowed, and cooperation between countries is needed for effective conservation and use of our global biodiversity. During the past...