Plant Science 156 (2000) 117 – 118
Book review
www.elsevier.com/locate/plantsci
Principles of Plant Breeding – Second Edition. Edited by Robert W. Allard, John Wiley & Sons Ltd. (ISBN-0-4710-2309-4); Price: £ 45.50
There cannot be many books about plant breed-ing that make for captivatbreed-ing readbreed-ing, but Allard’s second edition of the Principles of Plant Breeding is undoubtedly one of them. This edition is emi-nently more readable than the first. The chapters are separated into three parts, rather than the original, more cumbersome nine, with a greater emphasis being placed on the historical aspects and theories of plant breeding. Practical aspects of breeding are covered in part 3, but not before the foundations for understanding these principles have been elegantly laid out in parts 1 and 2.
Allard begins, at the very beginning, with the creation of the universe and the evolution of life. Darwin’s theories of selection emphasize the im-portance of nature, as well as man, as plant ‘breeder’, with Allards’ own experiments on the evolution of adaptiveness being elegantly pre-sented to illustrate this theme. Two seemingly opposite schools of thought are described in some depth; Mendel’s discovery of the orderliness of inheritance and Galton’s biometrical descriptors of continuous traits, which were united through the work of Johannsen and East who determined that a number of Mendelian units of inheritance could result in a continuous phenotype.
Several basic genetic principles are covered mathematically (e.g. outcrossing rates, heritability estimates, coefficients of inbreeding and fitness, random mating in small populations, genetic ad-vance under selection) but these do not weigh down the text too heavily. Many of the figures and photographs of the first edition have been re-moved so that illustrations are few and far be-tween. Two illustrations that remain are my old favorites and great teaching aids describing the smoothing influence of environment and gene
number on the distributions of discontinuous traits.
Two large parts of the original book; on host-pathogen genetics and polyploidy, have been re-moved. The chapters on the genetics of host-pathogen interactions and breeding for dis-ease resistance were comprehensive, but needed updating in light of more recent developments in this area. As this subject is sufficiently covered in numerous alternative texts, their removal is proba-bly appropriate. It is disappointing however that the chapters on polyploidy, still an important area of plant breeding, were removed.
Remarkable though this book is, it is written by one person and it does show. Allard’s own work on co-adapted gene complexes are emphasised and re-iterated throughout much of the book. The reliance on barley (for inbreeders) and maize (for outbreeders) to describe the progress that has been made through breeding means that equally impres-sive examples from other crop systems are ignored (for example, the work on tomato carried out by Allard’s coworkers within the same university). Obligate outbreeding crop systems are covered in very little depth. Surprisingly, apomixis, currently an important area of research, is dismissed as being of no relevance to plant breeding (despite a later advocation to fixing heterosis through clonal propagation).
Unexpectedly, this new edition does not address the impact of molecular markers and biotechnol-ogy on plant breeding. Molecular markers are covered to some extent but mainly to describe experiments on environmentally adapted gene complexes. Mapping and QTL mapping are ad-dressed with the description of a single paper on QTL interactions and the relationship between heterozygosity and heterosis. A host of comple-mentary papers are not discussed, including the excellent work of Stuber et al. on QTL mapping and heterosis. A passing comment on the use of
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gene cloning to manufacture pharmaceuticals in clonally propagated plants is the only acknowledg-ment given to biotechnology.
The book ends with a disappointing new chap-ter on breeding for low input systems. Allard merely melds together some information on G×E interactions and evolution of adaptiveness (again) to conclude that breeding for developing countries involves breeding for broadly adapted germplasm. Many obvious points concerning breeding for low input systems are not made, for example, the low relevance of the previously described dwarf sor-ghum varieties to subsistence farming is not com-mented on. Varieties bred specifically for developing countries are not described and new trends in participatory breeding and
socio-eco-nomical considerations are not addressed.
Ultimately, one cannot expect such a slim vol-ume to cover every aspect of breeding in depth and still remain an enjoyable read; those looking for a comprehensive and broadbased volume on all practical aspects of breeding should look else-where. Those looking to be inspired by the beauty of plant breeding should make this essential read-ing.
E. Jones
Plant Biotechnology Centre,
Agriculture Victoria,
Bundoora,
Victoria 3083,
Australia
