BOT312 — Conservation and Biodiversity: Lecture Note

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This is the complete lecture note for BOT312 Conservation and Biodiversity. 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.

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LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS • Course code: BOT312 • Course title: Conservation and Biodiversity • Course credit load: 3 Series 1: Plant Breeding Foundations Series outline • 1.1 Concepts of Plant Breeding o 1.1.1 Definition and Scope

LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS o 1.1.2 Historical Background • 1.2 Methods of Plant Breeding o 1.2.1 Conventional Methods o 1.2.2 Modern Approaches • 1.3 Applications of Plant Breeding o 1.3.1 Crop Improvement o 1.3.2 Biodiversity and Conservation Linkages • 1.4 Challenges and Future Directions o 1.4.1 Limitations of Current Methods o 1.4.2 Emerging Trends Introduction Plant breeding has long been a cornerstone of agriculture, shaping the way humans interact with plants to secure food, fibre, and other essential resources. From the earliest domestication of crops to modern scientific innovations, plant breeding has played a vital role in sustaining societies and addressing challenges such as food security and biodiversity conservation. As learners, you will find that understanding the foundations of plant breeding is crucial for appreciating its relevance to conservation and biodiversity, which are the central themes of this course. The aim of this Series is to equip you with a clear grasp of the concepts, methods, applications, and future directions of plant breeding, so that you can evaluate its role in conservation and resource management. We shall commence this Series by exploring the basic concepts of plant breeding, including its definition, scope, and historical background. Next, we will examine the methods of plant breeding, moving from conventional approaches to modern techniques. Following that, we will consider the applications of plant breeding, particularly in crop improvement and its linkages with biodiversity conservation. Finally, we will conclude by discussing the challenges faced in plant breeding and the emerging trends that point towards future directions. Series Learning Outcomes Upon completing this Series, you should be able to: • SLO 1.1 define the concept and scope of plant breeding, • SLO 1.2 explain the historical background and development of plant breeding, • SLO 1.3 describe conventional methods used in plant breeding,

LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS • SLO 1.4 analyse modern approaches to plant breeding, • SLO 1.5 evaluate the applications of plant breeding in crop improvement, • SLO 1.6 examine the linkages between plant breeding, biodiversity, and conservation, • SLO 1.7 assess the limitations of current plant breeding methods, and • SLO 1.8 discuss emerging trends and future directions in plant breeding. 1.1 Concepts of Plant Breeding 1.1.1 Definition and scope Plant breeding is the science and practice of altering the genetic makeup of plants to improve their characteristics for human use. It involves selecting desirable traits such as higher yield, disease resistance, or tolerance to environmental stress, and combining them through controlled reproduction. The scope of plant breeding extends beyond food crops to include fibre plants, ornamentals, and forestry species, making it a vital tool for agriculture and conservation. Plant breeding is not only about improving productivity, it also contributes to biodiversity by maintaining genetic variation within species. This variation is essential for resilience against pests, diseases, and climate change. Fill in the blank: Plant breeding is the science and practice of altering the ______ makeup of plants to improve their characteristics. Diagram showing the process of plant breeding from selection to hybridisation Caption: Figure 1.1 Process of plant breeding

LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS 1.1.2 Historical background The history of plant breeding dates back to the domestication of crops thousands of years ago. Early farmers selected plants with favourable traits, such as larger seeds or sweeter fruits, and propagated them. This simple form of selection laid the foundation for modern plant breeding. In the nineteenth century, the work of Gregor Mendel on genetics provided the scientific basis for inheritance, revolutionising plant breeding. Genetics is the study of heredity and variation in organisms. With Mendel’s principles, breeders could predict how traits would be passed on, making the process more systematic and reliable. The twentieth century saw the introduction of hybridisation, mutation breeding, and biotechnology, which expanded the possibilities of plant improvement. Today, plant breeding integrates traditional methods with advanced molecular techniques, ensuring crops meet the demands of growing populations and changing environments. Fill in the blank: The scientific basis of inheritance in plant breeding was established by ______ Mendel in the nineteenth century. Image of Gregor Mendel and pea plants used in his experiments Caption: Plate 1.1 Gregor Mendel and pea plant experiments Pilot questions 1.1 1. Which term refers to the science of altering plant genetics to improve traits? 2. What is one major contribution of plant breeding to biodiversity? 3. Who established the scientific basis of inheritance in plant breeding? 4. Name one modern technique used in plant breeding.

LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS 5. What was the earliest form of plant breeding practised by farmers? 1.2 Methods of Plant Breeding 1.2.1 Conventional methods Conventional methods of plant breeding rely on natural processes of reproduction and selection. These include mass selection, where large groups of plants are chosen based on desirable traits, and pure-line selection, where a single plant with favourable characteristics is propagated to produce uniform offspring. Another important method is hybridisation, which involves crossing two genetically different plants to combine their traits. These approaches have been used for centuries and remain effective for improving crops such as wheat, rice, and maize. However, they often require several generations to achieve stable results. Fill in the blank: The crossing of two genetically different plants to combine their traits is called ______. Diagram showing conventional plant breeding methods: mass selection, pure-line selection, and hybridisation Caption: Figure 1.2 Conventional methods of plant breeding 1.2.2 Modern approaches Modern approaches to plant breeding make use of scientific advances in genetics and biotechnology. One such method is mutation breeding, where mutations are induced using chemicals or radiation to create new traits. Another is tissue culture, which allows the growth of plants from small tissue samples under controlled conditions.

LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS The most significant modern technique is molecular breeding, which uses DNA markers to identify and select desirable traits more efficiently. In addition, genetic engineering enables the direct transfer of genes between species, producing genetically modified crops with enhanced qualities such as pest resistance or improved nutrition. These approaches have accelerated the pace of crop improvement and expanded the possibilities of plant breeding beyond what conventional methods can achieve. Fill in the blank: The use of DNA markers to identify and select desirable traits is known as ______ breeding. Box 1.1: Examples of modern plant breeding techniques • Mutation breeding • Tissue culture • Molecular breeding • Genetic engineering • Pilot questions 1.2 1. What is mass selection in plant breeding? 2. Which conventional method involves crossing two genetically different plants? 3. Name one technique used in mutation breeding. 4. What is the role of tissue culture in modern plant breeding?

LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS 5. Which modern approach uses DNA markers for trait selection? 1.3 Applications of Plant Breeding 1.3.1 Crop improvement One of the most important applications of plant breeding is crop improvement, which refers to the enhancement of crop traits to meet human needs. These traits may include higher yield, better nutritional quality, resistance to pests and diseases, and tolerance to environmental stresses such as drought or salinity. Crop improvement ensures food security and supports sustainable agriculture. For example, hybrid maize varieties have been developed to produce higher yields, while rice varieties have been bred to resist flooding. These improvements directly benefit farmers and consumers by increasing productivity and reducing losses. Fill in the blank: The enhancement of crop traits to meet human needs is known as ______ improvement. Diagram showing examples of crop improvement traits: yield, nutrition, pest resistance, stress tolerance Caption: Figure 1.3 Applications of plant breeding in crop improvement 1.3.2 Biodiversity and conservation linkages Plant breeding also plays a role in maintaining biodiversity, which is the variety of life forms within ecosystems. Biodiversity ensures ecological balance and resilience. Through careful breeding, genetic diversity within crop species can be preserved, reducing the risk of uniformity that makes crops vulnerable to pests and diseases.

LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Furthermore, plant breeding supports conservation by developing varieties that thrive in marginal environments, thereby reducing pressure on natural ecosystems. For instance, drought-tolerant crops allow farming in arid regions without overexploiting water resources. Fill in the blank: The variety of life forms within ecosystems is referred to as ______. Box 1.2: Linkages between plant breeding and conservation • Maintains genetic diversity within crops • Reduces vulnerability to pests and diseases • Supports farming in marginal environments • Lessens pressure on natural ecosystems • Pilot questions 1.3 1. What is crop improvement in plant breeding? 2.

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