Principles of Plant Genetics and Breeding

George Acquaah

• Publisher: Wiley-Blackwell
• Year: 2020
• ISBN:
  9781119626695
• Edition: 3
• Topic: Biological Sciences
• Subtopic: Botany
• Index: Biological Sciences

The revised edition of the bestselling textbook, covering both classical and molecular plant breeding

Principles of Plant Genetics and Breeding integrates theory and practice to provide an insightful examination of the fundamental principles and advanced techniques of modern plant breeding. Combining both classical and molecular tools, this comprehensive textbook describes the multidisciplinary strategies used to produce new varieties of crops and plants, particularly in response to the increasing demands to of growing populations. Illustrated chapters cover a wide range of topics, including plant reproductive systems, germplasm for breeding, molecular breeding, the common objectives of plant breeders, marketing and societal issues, and more.

Now in its third edition, this essential textbook contains extensively revised content that reflects recent advances and current practices. Substantial updates have been made to its molecular genetics and breeding sections, including discussions of new breeding techniques such as zinc finger nuclease, oligonucleotide directed mutagenesis, RNA-dependent DNA methylation, reverse breeding, genome editing, and others. A new table enables efficient comparison of an expanded list of molecular markers, including Allozyme, RFLPs, RAPD, SSR, ISSR, DAMD, AFLP, SNPs and ESTs. Also, new and updated "Industry Highlights" sections provide examples of the practical application of plant breeding methods to real-world problems. This new edition:

• Organizes topics to reflect the stages of an actual breeding project
• Incorporates the most recent technologies in the field, such as CRSPR genome edition and grafting on GM stock
• Includes numerous illustrations and end-of-chapter self-assessment questions, key references, suggested readings, and links to relevant websites
• Features a companion website containing additional artwork and instructor resources

Principles of Plant Genetics and Breeding offers researchers and professionals an invaluable resource and remains the ideal textbook for advanced undergraduates and graduates in plant science, particularly those studying plant breeding, biotechnology, and genetics.

Section 1
Overview and historical perspectives

• Chapter 1 Introduction
• Chapter 2 History of plant breeding

It is informative for students of plant breeding to have a historical perspective of the discipline. Understanding the timeline of advances in one's discipline is instructive in itself. It helps the student to put current advances in plant breeding in the proper perspective, appreciating the challenges and opportunities along the way as professionals contributed to knowledge in the discipline.

1
Introduction

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Purpose and expected outcomes

Agriculture is the deliberate planting and harvesting of plants and herding animals. This human invention has and continues to impact society and the environment. Plant breeding is a branch of agriculture that focuses on manipulating plant heredity to develop new and improved plant types for use by society. People in society are aware and appreciative of the enormous diversity in plants and plant products. They have preferences for certain varieties of flowers and food crops. They are aware that whereas some of this variation is natural, humans with special expertise (plant breeders) create some of it. Also, there is a general perception that such creations derive from crossing different plants. This introductory chapter is devoted to presenting a brief overview of plant breeding, including its benefits to society and some historical perspectives. After completing this chapter, the student should have a general understanding of:

1. The need and importance of plant breeding to society.
2. The goals of plant breeding.
3. The art and science of plant breeding.
4. Trends in plant breeding as an industry.
5. Selected milestones and accomplishments of plant breeders.
6. The future of plant breeding in society.

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1.1 What is plant breeding?

Plant breeding is a deliberate effort by humans to nudge nature, with respect to the heredity of plants, to an advantage. The changes made in plants are permanent and heritable. The professionals who conduct this task are called plant breeders. This effort at adjusting the status quo is instigated by a desire of humans to improve certain aspects of plants to perform new roles or enhance existing ones. Consequently, the term “plant breeding” is often used synonymously with “plant improvement” in modern society. It needs to be emphasized that the goals of plant breeding are focused and purposeful. Even though the phrase “to breed plants” often connotes the involvement of the sexual process in effecting a desired change, modern plant breeding also includes the manipulation of asexually reproducing plants (plants that do not reproduce through the sexual process). Breeding is hence about manipulating plant attributes, structure, and composition to make them more useful to humans. It should be mentioned at the onset that it is not every plant character or trait that is readily amenable to manipulation by breeders. However, as technology advances, plant breeders are increasingly able to accomplish astonishing plant manipulations – needless to say not without controversy, as is the case involving the development and application of biotechnology to plant genetic manipulation. One of the most controversial of these modern technologies is transgenesis, the technology by which gene transfer is made across natural biological barriers.

Plant breeders specialize in breeding different groups of plants. Some focus on field crops (e.g. soybean, cotton), horticultural food crops (e.g. vegetables), ornamentals (e.g. roses, pine trees), fruit trees (e.g. citrus, apple), forage crops (e.g. alfalfa, grasses), or turf species (e.g. Bluegrass, fescue). More importantly, breeders tend to specialize in or focus on specific species in these groups (e.g. corn breeder, potato breeder). This way, they develop the expertise that enables them to be most effective in improving the species of their choice. The principles and concepts discussed in this book are generally applicable to breeding all plant species.

1.2 The goals of plant breeding

The plant breeder uses various technologies and methodologies to achieve targeted and directional changes in the nature of plants (nudge nature to the advantage of humans). As science and technology advance, new tools are developed while old ones are refined for use by breeders. Before initiating a breeding project, clear breeding objectives are defined based on factors such as producer needs, consumer preferences and needs, and environmental impact. Breeders aim to make the crop producer's job easier and more effective in various ways. They may modify plant structure so it would resist lodging and thereby facilitate mechanical harvesting. They may develop plants that resist pests so the farmer does not have to apply pesticides, or apply smaller amounts of these chemicals. Not applying pesticides in crop production means less environmental pollution from agricultural sources. Breeders may also develop high yielding varieties (or cultivars) so the farmer can produce more for the market to meet consumer demands while improving his or her income. The term cultivar is reserved for variants deliberately created by plant breeders and will be introduced more formally later in the book. It will be the term of choice in this book.

When breeders think of consumers, they may, for example, develop foods with higher nutritional value and that are more flavorful. Higher nutritional value means reduced illnesses in society (e.g. nutritionally related ones such as blindness, rickettsia) caused by the consumption of nutrient‐deficient foods, as occurs in many developing regions where staple foods (e.g. rice, cassava) often lack certain essential amino acids or nutrients. Plant breeders may also target traits of industrial value. For example, fiber characteristics (e.g. strength) of fiber crops such as cotton can be improved, while oil crops can be improved to yield high amounts of specific fatty acids (e.g. high oleic content of sunflower seed). Latest advances in technology, specifically genetic engineering technologies, are being applied to enable plants to be used as bioreactors to produce certain pharmaceuticals (called biopharming or simply pharming).

The technological capabilities and needs of societies of old restricted plant breeders then to achieving modest objectives (e.g. product appeal, adaptation to production environment). It should be pointed out that these “older” breeding objectives are still important today. However, with the availability of sophisticated tools, plant breeders are now able to accomplish these genetic alterations in novel ways that are sometimes the only option, or are more precise and more effective. Furthermore, as previously indicated, they ...