Preface ix
Copyright acknowledgements xi
1 Introduction 1
2 Development and phenology 7
2.1 Crop development: concepts and tools 8
2.1.1 Growth stages and phasic development 9
2.1.2 Events at the stem apex: the leek as a simple model species 11
2.1.3 Events at stem apices: branching and reproductive development in wheat 13
2.1.4 Events at stem apices: the consequences of separation of male and female organs in maize 15
2.1.5 Phenology determined by events at axillary meristems: determinate and indeterminate soybean varieties 18
2.1.6 Components of yield 21
2.2 Case histories: the influence of environment and management on crop development and phenology 22
2.2.1 Convergence and synchrony: the influence of sowing date on winter wheat in Northern Europe 22
2.2.2 Crop improvement and the anthesis–silking interval in maize 25
2.2.3 Adaptation of soybean to different latitudes: phasic analysis of the photoperiodic control of flowering 26
2.2.4 Development in storage: physiological age and tuber initiation in the potato 30
2.2.5 Complementary phenologies and plant habits in mixed cropping: temperate grass/clover swards 32
3 Interception of solar radiation by the canopy 35
3.1 The life history of a leaf 35
3.2 The components of plant leaf area expansion 40
3.2.1 Crop emergence 40
3.2.2 Leaf production 41
3.2.3 Leaf expansion 43
3.2.4 Branching 47
3.2.5 Senescence, removal and damage – leaf lifespan 50
3.3 The development of the crop canopy: leaf area index 53
3.3.1 Seasonal development of leaf area index 53
3.3.2 Leaf area index and crop management 55
3.4 Canopy architecture and the interception of solar radiation 60
3.4.1 Seasonal patterns of interception 60
3.4.2 Optimum and critical leaf area indices 61
3.4.3 Leaf photosynthesis and canopy properties 63
3.4.4 Canopy extinction coefficient 66
4 Photosynthesis and photorespiration 73
4.1 Introduction 73
4.2 Photosynthetic efficiency 75
4.3 Photosynthetic processes 80
4.3.1 Photosynthesis as a cellular biochemical process 80
4.3.2 Photosynthesis as a leaf diffusive process 89
4.3.3 Photosynthesis as a crop canopy process 95
4.4 The C 4 photosynthesis mechanism 99
4.5 Water shortage and photosynthesis 104
4.6 Nitrogen effects on photosynthesis 109
4.7 Ozone effects on photosynthesis and crop productivity 112
5 The loss of CO 2 : respiration 117
5.1 Introduction 117
5.2 The basis of crop respiration 120
5.3 Growth and maintenance respiration 123
5.4 The respiration of different plant substrates 126
5.5 Growth and maintenance respiration in the field 130
5.6 Respiration associated with crop processes 134
5.7 Environmental effects on respiration 140
5.8 Crop respiration in the future 142
6 The partitioning of dry matter to harvested organs 145
6.1 The processes and pathways of assimilate partitioning 145
6.2 Ontogeny and assimilate partitioning: a survey of source/sink relationships 148
6.3 Time courses of dry matter partitioning: harvest index 151
6.4 Limitation of yield by source or sink 153
6.5 Sink limitation of yield in cereals – physiology of ineffective grain setting 157
6.6 Assimilate partitioning and crop improvement: historic trends in harvest index of wheat and barley 162
6.7 Assimilate partitioning and crop improvement: historic trends in harvest index of maize 165
6.8 Assimilate partitioning to potato tubers 167
6.9 Assimilate partitioning in grassland: implications for management of grass yield 171
6.10 Assimilate partitioning in grassland: implications for the overwintering and early growth of white clover 176
6. 11 Assimilate partitioning in diseased plants: temperate cereals affected by biotrophic fungal pathogens 178
7 Limiting factors and the achievement of high yield 180
7.1 Limitation by water supply 181
7.1.1 Acquisition of water 182
7.1.2 Water use efficiency 186
7.1.3 Crop yield where water supply is limiting 190
7.2 Limitation by nitrogen supply 193
7.2.1 Acquisition of nitrogen 193
7.2.2 Nitrogen use efficiency 196
7.2.3 Crop yield where N supply is limiting 200
7.3 Achieving high yield: resource capture and assimilate partitioning 202
8 Physiology of crop quality 205
8.1 Wheat: protein content 206
8.2 Soybean: oil and protein contents 209
8.3 Oilseed rape: glucosinolates and erucic acid 212
8.4 Potato: tuber size and processing quality 215
8.5 The quality of conserved forages: ontogeny and yield 217
9 The simulation modelling of crops 222
9.1 Introduction 222
9.2 Building a crop model 225
9.3 Crop models of wheat (AFRC2), soybean (CROPGRO) and maize 227
9.3.1 The AFRC2 wheat model 228
9.3.2 The CROPGRO soybean model 243
9.3.3 The maize model 253
9.4 Modelling variety differences and traits 257
9.5 Conclusions 261
10 Crop physiology: the future 264
10.1 Introduction 264
10.2 Lowering inputs 265
10.3 Climate change 267
10.4 Quality 269
10.5 New crops 270
10.6 The potential for increasing crop photosynthesis and yield 272
10.7 The last words 275
References 277
Index 309
