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This is the complete lecture note for BOT306 Plant Breeding. You can read it online below, open it in the full viewer, or download the PDF for offline study. It pairs with the course's video lectures, so you can read and watch together.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS • Course code: BOT306 • Course title: Plant Breeding • Course credit load: 3 Series 1: Objectives of Plant Breeding
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Series outline 1.1 Concept of Plant Breeding • 1.1.1 Definition of Plant Breeding • 1.1.2 Importance of Plant Breeding in Agriculture 1.2 Historical Perspective of Plant Breeding Objectives • 1.2.1 Early Goals of Plant Breeding • 1.2.2 Evolution of Objectives with Domestication 1.3 Major Objectives of Plant Breeding • 1.3.1 Yield Improvement • 1.3.2 Resistance to Diseases and Pests • 1.3.3 Adaptation to Environmental Conditions • 1.3.4 Quality Improvement (nutritional, industrial, aesthetic) 1.4 Contemporary and Future Objectives • 1.4.1 Sustainability and Climate Resilience • 1.4.2 Genetic Diversity and Conservation • 1.4.3 Meeting Global Food Security Needs Introduction Plant breeding has always been central to the progress of agriculture, shaping the crops that sustain human societies. From the earliest farmers who selected seeds for desirable traits, to modern scientists who employ advanced genetic tools, the objectives of plant breeding have continually evolved to meet the needs of humanity. Understanding these objectives provides a foundation for appreciating how crops are improved and adapted to changing environments, and why plant breeding remains vital for food security and sustainable development. The aim of this Series is to equip you with a clear understanding of the objectives of plant breeding, enabling you to analyse their historical roots, evaluate their current relevance, and anticipate future directions in crop improvement.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS We shall commence this Series by exploring the concept of plant breeding, including its definition and importance. Next, we will examine the historical perspective of plant breeding objectives, tracing how they have evolved over time. Following that, we will study the major objectives of plant breeding, such as yield improvement, resistance to diseases and pests, adaptation to environments, and quality enhancement. Finally, we will conclude by considering contemporary and future objectives, including sustainability, genetic diversity, and global food security. Series Learning Outcomes Upon completing this Series, you should be able to: • SLO 1.1 define the concept of plant breeding and explain its importance in agriculture, • SLO 1.2 analyse the historical development of plant breeding objectives, • SLO 1.3 evaluate the major objectives of plant breeding, including yield, resistance, adaptation, and quality, and • SLO 1.4 appraise contemporary and future objectives of plant breeding in relation to sustainability, diversity, and food security. 1.1 Concept Of Plant Breeding 1.1.1 Definition of plant breeding Plant breeding is the science and art of improving plants by altering their genetic makeup to produce desired characteristics. The term plant breeding refers to the deliberate manipulation of plant species to create varieties with improved yield, resistance, adaptability, or quality. It is both a scientific discipline, relying on genetics and biology, and a practical art, requiring skill and observation in selecting and crossing plants. Fill in the blank: Plant breeding is the ______ and art of improving plants by altering their genetic makeup.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Diagram showing the cycle of plant breeding from selection to improved variety. Figure 1.1: The plant breeding cycle 1.1.2 Importance of plant breeding in agriculture The importance of plant breeding lies in its ability to address fundamental agricultural challenges. By developing new crop varieties, breeders help ensure food security, improve nutritional quality, and enhance resilience against pests, diseases, and environmental stresses. For example, breeding for drought tolerance allows crops to thrive in water-scarce regions, while breeding for pest resistance reduces reliance on chemical pesticides. Fill in the blank: Breeding for ______ tolerance allows crops to thrive in water-scarce regions. Image of farmers examining improved crop varieties in a field. Plate 1.1: Farmers evaluating improved crop varieties
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Pilot questions 1.1 1. Plant breeding is defined as the science and art of what? 2. What is the main purpose of altering the genetic makeup of plants? 3. Name one agricultural challenge that plant breeding addresses. 4. Which trait allows crops to thrive in water-scarce regions? 5. Why is plant breeding considered both a science and an art? 1.2 Historical Perspective Of Plant Breeding Objectives 1.2.1 Early goals of plant breeding In the earliest days of agriculture, plant breeding was not a formal science but rather a practical activity carried out by farmers. The primary goal was to select plants that produced more food, tasted better, or were easier to cultivate. The term selection refers to the process of choosing plants with desirable traits to be grown and reproduced. Early farmers relied on observation and experience, gradually improving crops by saving seeds from the best-performing plants. Fill in the blank: Early farmers improved crops by saving seeds from the ______ plants. Box 1.1: Outline of early plant breeding goals
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS 1.2.2 Evolution of objectives with domestication As agriculture advanced, the objectives of plant breeding expanded. With the domestication of crops, breeders began to focus on traits such as uniformity, predictability, and adaptability to different environments. Domestication is the process by which wild plants are adapted for human use through cultivation and breeding. This shift allowed for more reliable harvests and the development of crops suited to specific regions. For instance, rice varieties were bred to thrive in flooded fields, while wheat was adapted to drier climates. Fill in the blank: Domestication is the process by which wild plants are adapted for ______ use through cultivation and breeding. Diagram showing the transition from wild plants to domesticated crops. Figure 1.2: Evolution of plant breeding objectives through domestication
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Pilot questions 1.2 1. What was the primary method used by early farmers to improve crops? 2. Define the term selection in the context of plant breeding. 3. What does domestication mean in plant breeding? 4. Name one trait that became important as crops were domesticated. 5. Give an example of a crop adapted to a specific environment through breeding. 1.3 Major Objectives Of Plant Breeding 1.3.1 Yield improvement One of the most important objectives of plant breeding is yield improvement, which refers to increasing the amount of crop produced per unit area. Higher yields ensure that farmers can produce more food to meet the demands of growing populations. Yield improvement is achieved through selecting and crossing plants that exhibit traits such as larger seeds, more fruits, or faster growth. Fill in the blank: Yield improvement refers to increasing the amount of crop produced per ______ area.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Diagram showing comparison between traditional and improved crop yields. Figure 1.3: Yield improvement through plant breeding 1.3.2 Resistance to diseases and pests Another major objective is breeding crops with resistance, which means the ability of plants to withstand or fight off diseases and pests. Resistant varieties reduce the need for chemical pesticides, making farming safer and more sustainable. For example, maize varieties resistant to stem borers or rice resistant to blast disease help farmers achieve stable harvests. Fill in the blank: Resistant varieties reduce the need for chemical ______.
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