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QUANTITATIVE GENETICS AND SELECTION

Quantitative Genetics and Selection in Plant Breeding by Giinter Wricke and W. Eberhard Weber. Walter de Gruyter, Berlin, New York, 1986, 406 pp., cloth, price DM 198.00/US$79.50, ISBN 0-89925-143-9 (US).

This book, as the title indicates, aims at presenting quantitative genetics with an emphasis on the principles of selection in plant breeding. It contains 13 chapters. Chapter 1 deals with the basic theory of population genetics. Genetic equilibrium problems with one or two loci with two or multiple alleles at one locus are considered in detail. The concepts of inbreeding, random drift and co-ancestry are also discussed in this chapter.

Chapters 2-4 cover various areas of quantitative genetics. Chapter 2 deals with the basic principle of genetic modelling. It covers genetic and statistical aspects of components of variances and covariances. Covariances between rel- atives are discussed in Chapter 3, and Chapter 4 describes experiments which can be used for the estimation of genetic variances and covariances.

The remaining 9 chapters ( Chaps. 5-13) are concentrated on selection the- ory and its use in plant breeding. The first section of Chapter 5 discusses nat- ural selection. The rest of the book, however, is mainly devoted to artificial selection as practiced in plant breeding. Chapters 6, 10 and 11 separately dis- cuss selection between clones and homozygous lines (Chap. 6), in segregating generations of self-fertilizing crops (Chap. 10) and in autotetraploids (Chap. 11). Three chapters are used to present various topics on selection in cross- fertilized crops: Chapter 7 on population improvement; Chapter 8 on synthetic varieties; Chapter 9 on hybrid varieties. The final two chapters deal with mul- tiple-trait selection (Chap. 12) and selection progress and selection limits (Chap. 13).

A unique feature of the book is that all topics are organized according to the natural reproduction systems of crop plants, i.e. vegetatively propagated, cross- fertilized, self-fertilized and autotetraploid species. This arrangement does create a problem for presenting a coherent theory on subjects of common inter- est among all crop species, e.g. heritability, phenotypic stability, diallels, etc., but the advantages probably outweigh such concerns, as the presentation clearly relates crop species to special areas of quantitative genetics and selection the- ory. It is inevitable that the cross-fertilized crop species take the lions share of the pages in the book.

There are places in the book where the definition and/or description are not clear. For example, Pj=Gj+Ej (p. 41 ), P=G+E (p. 42) andp=g+e (p. 179)

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are all meant for the same model. The G in these formulae is different from the G in G = A + D on p. 47. The symbols V and a are used interchangeably. One may prefer to use V as representing variance, but a for variance components. The term "path coefficient" is mentioned (p. 17 ) without a definition.

It is also debatable whether the standardized selection response can be defined as the selection response (p. 162). This deviates from the use of the "unstan- dardized" one as the measure of selection response in the literature. The stand- ardized measure gives some statistical convenience, such as obtaining variance of selection response and constructing a confidence interval for the predicted response, but it neglects the importance of the size of genotypic variance which, together with i and pxy, determines the actual response to selection.

All in all, this book provides a rich source of information on quantitative genetics and particularly on selection theory in crop plants. It is a welcome addition in the fields of plant genetics and breeding. As the authors state in the preface, it is for students in plant breeding and genetics, as well as for plant breeders and applied geneticists.

G.C.C. TAI Agriculture Canada Research Station

P.O. Box 20280 Fredericton, New Brunswick E3B 4Z7

Canada

PLANT SENESCENCE

Processes and Control of Plant Senescence by Y.Y. Leshem, A.H. Halevy and C. Frenkel, Developments in Crop Science, Vol. 8. Elsevier Science Publish- ers, P.O. Box 330, 1000 AH Amsterdam, The Netherlands, 1986, xi+215 pp., illus., price hardcover US$ 64.75/Dfl. 175.00, ISBN 0-444-42521-7.

Senescence is a morphogenetic plant process which is of great importance in horticultural practice. Manipulation of the lifespan of harvested seeds, veg- etables, fruits and cut flowers results from knowledge of the fundamental pro- cesses underlying plant senescence syndrome. This monograph provides basic and empiric information on this subject. The three authors are all specialists in the field, but their contributions to the book are somewhat unbalanced. Dr. Leshem wrote 6 chapters, Dr. Halevy 2 chapters and Dr. Frenkel only one. Dr. Frimer wrote the major part of a chapter on oxidative processes.

The monograph is divided into three parts. Part 1 gives a general introduc- tion to plant senescence, Part 2 discusses senescence factors such as ethylene and abscisic acid and gives extended information on the relationships between membranes, oxidative processes in biological systems, free radicals and senes- cence, and Part 3 describes senescence in various plant organs.