Plant Breeding: Principles, Methods and applications
Plant breeding as a science matured after Gregor Mendel’s laws of inheritance were rediscovered in 1900. These principles laid the foundation for understanding how traits are passed from one generation to the next. The emergence of classical genetics enabled breeders to create better crop varieties in a more systematic manner. Over time, breeders developed numerous successful cultivars by selecting plants with desirable traits, hybridizing different varieties, and applying knowledge of heredity to predict outcomes. This led to the development of high-yielding, pest-resistant, and climate-adapted crops that helped stabilize food production in many parts of the world. One of the most transformative events in agricultural history was the Green Revolution of the 1960s and 70s. Scientists such as Norman Borlaug pioneered the development of dwarf wheat and rice varieties that dramatically increased food production in Asia and Latin America. These varieties were not only high-yielding but also responded well to fertilizers and irrigation, thereby transforming previously food-deficient nations into self-sufficient or even surplus-producing countries. This revolution in breeding was pivotal in averting famines and reducing hunger. Today, plant breeding is a multidisciplinary science that includes classical techniques and modern innovations like molecular breeding, bioinformatics, and genetic engineering. The objectives of modern plant breeding go beyond yield improvement. They include enhancing nutritional value, increasing resistance to pests and diseases, improving tolerance to abiotic stresses like drought and salinity, and developing varieties suited to mechanized farming. Breeders also aim to produce crops with better post-harvest qualities such as longer shelf life, improved flavor, and higher processing efficiency. Plant breeding is the science, art, and business of improving plants for human benefit. It involves the deliberate manipulation of plant species to create desired genotypes and phenotypes for specific purposes. This age-old practice has evolved from simple selection in ancient times to a sophisticated discipline that integrates genetics, molecular biology, and biotechnology. The primary goal of plant breeding is to develop crop varieties that are more productive, resilient, and suitable for diverse environments and consumer needs. With the global population rising and agricultural lands diminishing, the need for efficient and sustainable crop production has never been more urgent. Plant breeding plays a vital role in addressing these challenges by producing high-yielding, disease-resistant, and climate-resilient crops. The field continues to evolve with modern tools such as genomic selection, CRISPR gene editing, and marker-assisted selection, promising more precise and faster improvements. The practice of plant breeding can be traced back over 10,000 years to when early humans first began cultivating wild plants.
Plant Breeding: Principles, Methods and applications
- 1. Topic:-Plant breeding Sub-topic:-Selection methods in cross pollinated crops. Laxman Khatal M.Sc By BO11733:Genetics and plant breeding
- 2. What is Plant Breeding? "Plant Breeding is the art and science of the genetic improvement of plants." or ‘‘Plant breeding is the purposeful manipulation of qualities in plants to create new varieties with a set of desired characteristics.’’ Plants with higher qualities are selected by and crossed to obtain plants with desired quality. This results in a plant population with improved and desired traits.
- 3. Objectives: Following are the major objectives of plant breeding: To increase the crop yield. To raise plants with desired characteristics. To develop a disease-resistant crop. To develop plants that can tolerate extreme environmental stress.
- 4. Concept of cross-pollination “A type of pollination in which the pollen from the anther of a flower is transferred to the stigma of a flower of another plant” Means Cross-pollination is the deposition of pollen grains from one flower to the stigma of another flower. Commonly, the process is done by insects and wind.
- 5. Methods of breeding cross pollinated crops (i) Selection method (ii)Plant introduction (iii) Heterosis breeding (iv) Synthetic breeding (v) Composite breeding (vi) Backcross method (vii) Polyploidy breeding (viii) Transgenic breeding (ix) Molecular breeding etc.
- 6. Selection is the basis of plant breeding. When we talk about selection as plant breeders, we are referring to artificial selection we walk into our field and advance a subset of plant individuals (by saving their seeds/tubers/cuttings and replanting them) that meet our objectives. Selection method
- 7. Selection (Population improvement) A)Without progeny testing Mass selection B) With progeny testing a)Progeny testing i. Plant to row ii. Ear to row b)Recurrent selection iii. Simple recurrent selection iv. Recurrent selection for GCA (General combining ability) v. Recurrent selection for SCA (Specific combining ability)
- 8. Mass selection Mass selection in cross-pollinated species takes the same form as in self-pollinated species. A large number of superior appearing plants are selected and harvested in bulk and the seed used to produce the next generation. Mass selection has proved to be very effective in improving qualitative characters, and, applied over many generations, it is also capable of improving quantitative characters, including yield despite the low heritability of such characters. Mass selection has long been a major method of breeding cross-pollinated species, especially in the economically less important species.
- 9. Types of mass selection It can be of two types as given below. Positive mass selection. When desirable plants are selected from a mixed population and their seeds are mixed together to grow further generation, it is referred to as positive mass selection. This process is continued for several years. Negative mass selection. This is generally used for varietal purification in seed production and certification programmes. This helps to maintain a high level of genetic purity in varieties.
- 10. Procedure:
- 11. Achievements of mass selection cross pollinated crops: