Principles and Techniques of Plant Breeding

The world’s population is growing. Demand for food and water is increasing. Over the next few decades, food production will need to increase dramatically to keep pace with population growth and meet the needs of changing diets. To do that, farmers will need to grow as much food in the next 50 years as they did in the past 10,000 years of farming combined, while managing with a declining amount of resources. To successfully accomplish these goals, innovations in plant sciences must be at the forefront of what we do. Advances in plant breeding are helping increase the rate of improvement in key plant characteristics, such as grain yield and disease tolerance. Plant breeding is the process by which humans change the characteristics of plants over time to make them better crops and more nourishing food. In its most simple form, breeding consists of selecting the best plants in a given field, growing them to full seed and then using that seed to grow further generations. Plant breeding can be accomplished through many different techniques ranging from simply selecting plants with desirable characteristics for propagation, to more complex molecular techniques. Plant breeding has been practiced for thousands of years, since near the beginning of human civilization. It is now practiced worldwide by individuals such as gardeners and farmers, or by professional plant breeders employed by organizations such as government institutions, universities, crop-specific industry associations or research centers. Plant breeding in certain situations may lead the domestication of wild plants. Domestication of plants is an artificial selection process conducted by humans to produce plants that have more desirable traits than wild plants, and which renders them dependent on artificial (usually enhanced) environments for their continued existence. A plant whose origin or selection is due primarily to intentional human activity is called a cultigen, and a cultivated crop species that has evolved from wild populations due to selective pressures from traditional farmers is called a landrace. Landraces, which can be the result of natural forces or domestication, are plants (or animals) that are ideally suited to a particular region or environment. An example are the landraces of rice, Oryza sativa subspecies indica, which was developed in South Asia, and Oryza sativa subspecies japonica, which was developed in China. Consequently, Plant breeding is the purposeful manipulation of plant species in order to create desired genotypes and phenotypes for specific purposes.