Wheat: Science and Trade

Foreword xvii

Preface xix

Acknowledgements xxi

Contributors xxiii

Section I: Making of a Wheat Plant 3

1 Wheat evolution, domestication, and improvement 5

Summary 5

Introduction 5

Wheat domestication and human civilization 6

Wheat cultivation 7

Origin, domestication, and evolution of wheat 8

Genome evolution and modification 16

Mechanisms for chromosome evolution 18

The potential of wild emmer in wheat improvement 21

Concluding remarks on the process of wheat evolution 22

Future perspectives 23

References 23

2 Development of the wheat plant 31

Summary 31

Introduction 31

Scales of plant development 323

Morphological naming schemes 34

Shoot development 35

Environmental factors influencing shoot development 42

Digital technologies for wheat development 47

Linking molecular biology and functional genomics to development 49

Future perspectives 50

References 50

3 The flowering pathway in wheat 57

Summary 57

Overview of flowering induction in wheat 57

Genetic locations of flowering time genes 58

Positional cloning of flowering time genes in wheat 61

Comparative studies on flowering pathways in plants 65

Future perspectives 67

References 68

Section II: Making of a Wheat Crop 73

4 Systems-based wheat management strategies 75

Summary 75

Introduction 75

Advances in wheat management 75

Dual-purpose wheat 79

No-till wheat production 82

Future perspectives 84

References 86

5 Diseases which challenge global wheat production—the wheat rusts 89

Summary 89

Introduction 90

Wheat leaf rust 90

Wheat stripe rust 102

Wheat stem rust 109

Future perspectives 116

References 117

6 Diseases which challenge global wheat production—root, crown, and culm rots 125

Summary 125

Introduction 125

Common root rot 126

Fusarium crown rot 129

Pythium root rot 131

Rhizoctonia root rot and bare patch 134

Take-all 136

Cephalosporium stripe 139

Eyespot 141

Future perspectives 142

References 144

7 Diseases which challenge global wheat production—powdery mildew and leaf and head blights 155

Summary 155

Introduction 155

Powdery mildew 156

Stagonospora nodorum blotch 157

Septoria tritici blotch 158

Tan spot 159

Fusarium head blight 160

Management of residue-borne diseases 161

Future perspectives 163

References 164

8 Nematodes which challenge global wheat production 171

Summary 171

Introduction 171

Cereal cyst nematode 172

Root-lesion nematode 177

Future perspectives 182

References 183

9 Insects which challenge global wheat production 189

Summary 189

Hessian fly 189

Bird cherry–oat aphid 192

Greenbug 194

Russian wheat aphid 196

Future perspectives 198

References 199

10 Temporally and spatially dependent nitrogen management for diverse environments 203

Summary 203

Introduction 203

Nitrogen-use efficiency as a driver of new technology 204

Case study: What defines diverse environments 205

Is nitrogen needed 206

Nutrient deficiencies other than N 209

Prediction of yield potential 209

Prediction of N responsiveness independent of yield potential 210

Midseason N applications can result in maximum yields 210

Determination of midseason N rate 211

“Ramp” method of determining midseason N rate 212

Future perspectives 213

References 213

11 Grain yield improvement in water-limited environments 215

Summary 215

Introduction 215

Climate and crop growth 216 Water-limited yield potential 218

Characterizing target environments 219

Breeding for improved performance under drought 221

Breeding tools 224

Defining the breeding target 231

Future perspectives 243

References 243

12 Cutting down on weeds to cut a cleaner wheat crop 251

Summary 251

Impact of weeds on wheat 252

Controlling weeds with integrated weed management systems 256

Weed spatial variation and precision farming 263

Putting it all together: Examples of effective systems 264

Future perspectives 268

References 268

Section III: Making of a Wheat Cultivar 273

13 Wheat breeding: Procedures and strategies 275

Summary 275

Brief history of wheat breeding 276

The context of applied wheat breeding 277

Accessing genetic resources 277

Methods to generate genetic variation 279

Methods to assess genetic variation 284

Methods of selecting while inbreeding to develop a cultivar 285

Major issues all wheat breeders face 293

The practice of wheat breeding 296

Breeding hybrid wheat 300

Importance of technology 301

Future perspectives 301

Webliography 303

References 304

14 State of QTL detection and marker-assisted selection in wheat improvement 309

Summary 309

Introduction 309

Breeding by visual selection 310

Complex traits and gene pyramiding 311

Genetic mapping 311

Early progress and developments 313

Current progress in QTL analysis and deployment of MAS 316

Complex traits 319

Future developments and uses of QTL analysis and mapping 320

Future perspectives 321

References 322

15 Genome organization and comparative genomics 327

Summary 327

Mapping 328

Comparative genetics 330

Map-based cloning 335

Physical mapping in hexaploid wheat 342

Organization and evolution of the wheat genome 349

Toward sequencing the wheat genome 353

Future perspectives 357

References 359

16 Synthetic wheat—an emerging genetic resource 369

Summary 369

Introduction 369

Primary synthetic hexaploid wheat 371

Strategies for using primary synthetics in applied wheat breeding 377

Performance of derived synthetics 378

Future perspectives 380

References 381

17 Success in wheat improvement 387

World yield gains 387

Genetic component of grain yield improvement 388

Empirical estimation of genetic gain 389

Wheat yield gains in light of other crops 392

Future perspectives 393

References 394

18 Transgenic applications in wheat improvement 397

Summary 397

Introduction 398

Wheat transformation: Methods and results 398

Applications of wheat transformation 404

Limitations of wheat transformation technology 418

Future perspectives 424

References 426

Section IV: Making of a Wheat Industry 437

19 Overview of wheat classification and trade 439

Summary 439

Introduction 439

World production 439

Global wheat trade 440

Fundamental wheat classification criteria 444

US system of wheat classification 444

Canadian system of classification and marketing 449

Australian system of classification and marketing 450

Purchasing decision making 450

Grain exchanges 451

Future perspectives 453

References 454

20 Passing the test on wheat end-use quality 455

Summary 455

Introduction 455

Characteristics of major wheat-based foods 457

Compositional analysis and grain testing 465

Starch and flour properties 472

Solvent retention capacity 475

Dough testing and prediction of dough properties 476

End-product testing 482

Emerging opportunities 483

Future perpectives 485

References 486

21 The biochemical and molecular basis of wheat quality 495

Summary 495

Introduction 496

Diversity of wheat utilization 496

Processing specifications for wheat utilization 499

Protein composition and wheat quality 500

Lipid composition and wheat quality 506

Starch composition and wheat quality 509

Nonstarch polysaccharide composition and wheat quality 512

Flour color and wheat quality 513

Enzymes and wheat quality 514

Selection for wheat quality in breeding 516

Future perspectives 516

References 517

22 New uses for wheat and modified wheat products 521

Summary 521

Introduction 521

White wheat 523

Low polyphenol oxidase wheat 526

Altered starch 527

Wheat phytochemicals 532

Industrial wheat 538

Future perspectives 543

References 544

23 US wheat marketing system and price discovery 551

Summary 551

Introduction 551

Marketing system 551

Physical flow of wheat 555

Cash prices 555

Quality discounts and premiums 556

Future perspectives 556

Reference 556

Index 557