Book Review

to farmers'. Genetic diversity is needed to make advances in plant breeding; and breeders use the genetic resources safely conserved in genebanks around the world to enhance crop productivity and safeguard food security. In a number of crops there is concern that the pool of diversity that sustains them is just too narrow, due to a variety of genetic bottlenecks through domestication or breeding. This could lead, once again, to calamities such as the potato famine in Ireland in the 1840s (caused by the late blight fungus), and the more recent 1970 southern leaf blight epidemic that devastated the US maize crop. The book comprises 27 chapters in four parts: I. General principles; II. Crop case studies; III. Population management; and IV. Other approaches to broadening the genetic base of crops, contributed by 127 authors. In the seven chapters of Part 1, the topics range from an overview of the central issues by the editors of the book, to reviews of the dynamics of crop genepools (this is an excellent chapter by Charlie Spillane and Paul Gepts), an analysis of base-broadening through introgression, local-level gene ̄ow systems, regulatory aspects of breeding, decentralized and participatory breeding in marginal environments (by Ceccarelli et al., pioneers in this ®eld from ICARDA in Syria) and ®nally, empowering rice farmers, a perspective from the civil society community in the Philippines. There are ®ve crop case studies in Part II: on millet in West Africa; a comparison of maize diversity use in the USA and subSaharan Africa; potato; cassava; and banana (Musa spp.). In Part III, dealing with population management in eight chapters, the crops covered include wheat, barley (two chapters), sugarcane, Beta and maize (three chapters). The seven chapters of Part IV cover a range of crops (lentil, barley, Phaseolus beans, potato), and more wide-ranging analyses of decentralized and participatory plant breeding approaches. On ®rst reading, it does appear that there is some duplication among sections and chapters, and perhaps a disproportionate number of chapters on barley and maize for example. Nevertheless, the emphasis on each crop in the di€erent sections is complementary, and perhaps focusing on a few crops does provide a broad perspective of the challenges that they face. However, the omission of rice per se is regrettable given that it is the world's most important staple food crop and the advances that have been made to exploit diversity through conventional and non-conventional approaches. Reference is made to rice in other chapters, and rice farming is the central theme of the chapter by Salazar on farmer empowerment. Also included is a ®nal statement from the workshop participants, with a six-point plan that FAO should adopt to launch a `Base-broadening Initiative', in collaboration with a range of organizations worldwide. This plan should bring together international networks of partners (using existing crop networks where possible), to review the state of diversity in speci®c crops, facilitate the development of long-term projects, enhance training particularly in developing countries and in the relevant disciplines, especially population genetics, build upon the community-based initiatives that have been started in some countries, and promote awareness at the policy and technical levels. With this FAO-led initiative, there is hope for meeting the challenges that the narrow genetic base of many crops raises. In all chapters the authors have provided comprehensive reviews of the topics assigned to them, and the literature cited is extensive. Fortunately, many of the cited publications are more recent than the 1997 date of the meeting. In conclusion, it is easy to commend this book to researchers in crop science who wish to gain a good insight into the `state of play' regarding base-broadening e€orts. The book has been carefully edited and there appear to be few typographical errors. The illustrations (all line drawings) are useful, although one or two seem a little `clever'. Nevertheless, these proceedings provide an excellent balance of theoretical analyses of basebroadening counterbalanced by speci®c and concrete examples of how this is being achieved. Given its sound scienti®c content, and that books nowadays can be very expensive, this joint CABIFAO-IPGRI publication is good value for money.