1 The Evolution of Crops
1.1 General
1.2 Time scales
1.3 Geography of crop evolution 10
1.4 People
1.5 Plant sources and products
1.6 Evolutionary processes
1.7 Summary
1.8 Literature
2 Basic Features of Plant Breeding
2.1 Introduction 27
2.2 Objectives and decisions 27
2.3 The pattern of peluit breeding 30
2.4 Supplementary techniques - biotechnology 33
2.5 The social context 36
2.6 Summary 37
2.7 Literature 37
3 Objectives of Plant Breeding 39
3.1
Introduction
3.2
Yield
3.3
Quality
3.4
Other objectives
3.5
Interactions
3.6
Conclusions
3.7
Summary
3.8
Literature
Genetic Aspects: Populations and Selection
4.1 Introduction ^2
4.2 Genotype and phenotype 62

vi Contents
4.3 Some ideas in population genetics 66
4.4 Oligogenic and polygenic 76
4.5 Heritability
4.6 Response to selection 91
4.7 Combining ability jq2
4.8 Heterogeneity, heterozygosity and stability 108
4.9 Summary HI
4.10 Literature 1^3
5 Breeding Plans
5.1 Introduction 21^
5.2 The four basic schemes 125
5.3 Inbred lines 22^
5.4 Open-pollinated populations 125
5.5 Hybrid varieties 135
5.6 Clones
5.7 Backcrossing 25g
5.8 Selection
5.9 Breeding strategy 1^3
5.10 Summary ^gg
5.11 Literature
6 Trials and Multiplication 2
6.1 Introduction 104
6.2 Trials 94
6.3 Requirements and conditions 207
6.4 Multiplication 212
6.5 Summary 224
6.6 Literature
7 Disease Resistance
7.1 General
7.2 Disease resistance 233
7.3 Epidemics, populations and the genetic base 246
7.4 Breeding 252
7.5 Summary 259
7.6 Literature 260
8 Special Techniques 252
8.1 Introduction
8.2 Polyploidy
8.3 Wide crossing «
8.4 Haploidy
8.5 Induced mutations 277
8.6 Summary
8.7 Literature
9 Biotechnology and Crop Improvement 285
S.Millam and W. Spoor
9.1 Introduction
9.2 Plant cell and tissue culture 285
9.3 Transgenic plant technology 289
9.4 Target traits for transformation 294
9.5 Molecular applications to crop improvement 300
9.6 Summary
9.7 Literature
10 New Crops and Genetic Conservation 306
10.1 Introduction
10.2 New crops
10.3 Genetic conservation
10.4 Use of collections: base broadening 324
10.5 Summary ^29
10.6 Literature
11 The Social Context
11.1 Introduction
11.2 Agricultural research and development 331
11.3 Profits, costs and benefits 333
11.4 Tropical development 347
11.5 Summary 357
11.6 Literature 358