Genetic variability is an important parameter for plant breeders in any con ventional crop improvement programme. Very often the desired variation is un available in the right combination, or simply does not exist at all. However, plant breeders have successfully recombined the desired genes from cultivated crop gerrnplasm and related wild species by sexual hybridization, and have been able to develop new cultivars with desirable agronomie traits, such as high yield, disease, pest, and drought resistance. So far, conventional breeding methods have managed to feed the world's ever-growing population. Continued population growth, no further scope of expanding arable land, soil degradation, environ mental pollution and global warrning are causes of concern to plant biologists and planners. Plant breeders are under continuous pressure to improve and develop new cultivars for sustainable food production. However, it takes several years to develop a new cultivar. Therefore, they have to look for new technologies, which could be combined with conventional methods to create more genetic variability, and reduce the time in developing new cultivars, with early-maturity, and improved yield. The first report on induced mutation of a gene by HJ. Muller in 1927 was a major mi1estone in enhancing variation, and also indicated the potential applica tions of mutagenesis in plant improvement. Radiation sources, such as X-rays, gamma rays and fast neutrons, and chemical mutagens (e. g. , ethyl methane sulphonate) have been widely used to induce mutations.

"The book...is, in fact, a short text on the many practical problems...associated with translating the explosion in basic biotechnological research into the next Green Revolution," explains Economic Botany. The book is "a concise and accurate narrative, that also manages to be interesting and personal...a splendid little book." Biotechnology states, "Because of the clarity with which it is written, this thin volume makes a major contribution to improving public understanding of genetic engineering's potential for enlarging the world's food supply...and can be profitably read by practically anyone interested in application of molecular biology to improvement of productivity in agriculture."

Major and exciting changes have taken place recently in various aspects of bio technology and its applications to forestry. Even more exciting is the prospect of major innovations that the entire field of biotechnology holds for plant growth in general. The importance of these developments for the forestry sector is considerable, particu larly since forestry science has not received the kinds of technical and R&D inputs that, say, agriculture has received in the past few decades. Y ct the problems of defor estation as well as stagnation in yields and productivity of existing forests throughout the world are becoming increasingly apparent, with consequences and ecological ef fects that cause growing worldwide concern. Policies for application of existing knowl edge in biotechnology to the field of forestry and priorities for future research and development are, therefore, of considerable value, because it is only through the adop tion of the right priorities and enlightened policies that scientific developments will move along the right direction, leading to improvements in forestry practices through out the world. It was against this backdrop that the Tata Energy Research Institute (TERI) or ganised a major international workshop on the "Applications of Biotechnology in For estry and Horticulture" at New Delhi in January 1988. The present volume covers the proceedings of this international workshop.

Plant Regeneration and Genetic Variability

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.

This anchor volume to the series Managing Global Genetic Resources examines the structure that underlies efforts to preserve genetic material, including the worldwide network of genetic collections; the role of biotechnology; and a host of issues that surround management and use. Among the topics explored are in situ versus ex situ conservation, management of very large collections of genetic material, problems of quarantine, the controversy over ownership or copyright of genetic material, and more.

Micropropagation has become a reliable and routine approach for large-scale rapid plant multiplication, which is based on plant cell, tissue and organ culture on well defined tissue culture media under aseptic conditions. A lot of research efforts are being made to develop and refine micropropagation methods and culture media for large-scale plant multiplication of several number of plant species. However, many forest and fruit tree species still remain recalcitrant to in vitro culture and require highly specific culture conditions for plant growth and development. The recent challenges on plant cell cycle regulation and the presented potential molecular mechanisms of recalcitrance are providing excellent background for understanding on totipotency and what is more development of micropropagation protocols. For large-scale in vitro plant production the important attributes are the quality, cost effectiveness, maintenance of genetic fidelity, and long-term storage. The need for appropriate in vitro plant regeneration methods for woody plants, including both forest and fruit trees, is still overwhelming in order to overcome problems facing micropropagation such as somaclonal variation, recalcitrant rooting, hyperhydricity, polyphenols, loss of material during hardening and quality of plant material. Moreover, micropropagation may be utilized, in basic research, in production of virus-free planting material, cryopreservation of endangered and elite woody species, applications in tree breeding and reforestation.