What Are the Main Methods and Benefits of Plant Breeding?
Plant Breeding began with sedentary agriculture and the domestication of agricultural plants, a practice that dates back almost 9000 to 11000 years. Back then, the farmers just selected the food plants having some desirable characteristics. It has been practised globally by farmers and gardeners. It has also been employed by professional plant breeders who are employed by different organisations like universities, government institutions, research centres, or crop-specific industry associations.
The process known as participatory Plant Breeding is utilised by the farmers for getting involved in Plant Breeding constantly. The international development agencies reckon that the breeding of new crops is essential for ensuring food security through the development of new varieties which are disease-resistant, higher-yielding, drought-tolerant, and regionally adapted for different growing conditions and environments.
Plant Breeding - Breeding for Disease Resistance requires
Plant Breeding is essentially the science of adjusting or modifying the traits of the plants to supply the required characteristics. One of the primary objectives of the Plant Breeding process is to supply the crop varieties that boost the superior as well as unique traits for the propagation of agricultural applications. Plant Breeding, also known as crop breeding, is accomplished using various techniques that start from selecting plants having desirable characteristics for the purpose of propagation, to using the data related to chromosomes and genetics.
The Different Types of Plant Breeding Processes
The various types of Plant Breeding processes that exist include Inbreeding, Backcrossing, Mutation breeding, Hybrid breeding, and Genetic engineering. All of these processes involve their own distinct methods as well as techniques that contribute towards the boost or productivity of the crops in several ways.
Plant Breeding and Genetics
Gregor Mendel (1822–84) is taken into account as the "father of genetics". He has developed the laws of inheritance with the help of experiments with plant hybridization. Genetics stimulated research to enhance crop production through Plant Breeding.
Genetic modification of plants is achieved by adding a selected gene or genes to a plant, or by demolition of a gene with RNAi, to supply a desirable phenotype. The plants resulting from adding a gene are often mentioned as transgenic plants. If genetic modification genes of the species or of a crossable plant are used in check of their native promoter, then they're called cisgenic plants. Sometimes genetic modification can produce a plant with the specified trait or traits faster than classical breeding because the bulk of the plant's genome isn't altered.
Modern Plant Breeding
Modern Plant Breeding is Applied Genetics, covering Biology, Cytology, Physiology, Pathology, Entomology, and Statistics. It has also developed its own technology.
Sometimes many various genes can influence a desirable trait in Plant Breeding. The use of tools like molecular markers or DNA fingerprinting can map thousands of genes. This allows plant breeders to screen large populations of plants for people who possess the trait of interest. The screening is predicated on the presence or absence of a particular gene as determined by laboratory procedures, instead of on the visual identification of the expressed trait within the plant.
Classical Plant Breeding or Conventional Plant Breeding
One major technique of Plant Breeding is selection, the method of selectively propagating plants with desirable characteristics and eliminating or "culling" those with less desirable characteristics.
Conventional breeding relies largely on homologous recombination between chromosomes to get genetic diversity. The classical plant breeder can also make use of various types of in vitro techniques such as protoplast fusion, embryo rescue, or mutagenesis to get diversity and produce hybrid plants that might not exist in nature.
Traits that breeders have tried to include into crop plants include:
Improved quality, like increased nutrition, improved flavour, or greater beauty
Increased yield of the crop
Increased tolerance of environmental pressures (salinity, heat, drought)
Resistance to viruses, fungi, and bacteria
Increased tolerance to insect pests
Increased tolerance of herbicides
Longer storage period for the harvested crop
Another technique is the deliberate interbreeding of closely or distantly related individuals to supply new crop varieties or lines with desirable properties. Cross breeding plants are used to introduce traits or genes from one variety or line into a replacement genetic background.
Issues and Concerns related to Plant Breeding
Classical Plant Breeding, modern Plant Breeding, or Plant Breeding through the process of gene-splicing, each come with their own concerns related to the food crops. There is an ever-present question of whether the breeding process can have a negative impact on the nutritional value of the crops.
According to one of the studies that was published in the Journal of the American College of Nutrition in 2004 with entitled changes in USDA Food Composition Data for the 43 garden corps between 1950 and 1999 compared the nutritional analysis of the vegetables between those years, it observed substantial decrease within 6 of the 13 nutrients that were measured. This includes 38% riboflavin and 6% protein. The reductions in phosphorus, vitamin C, iron, and calcium were also found. Thus the issues related to the nutritional value of the crops related to the process of Plant Breeding continues to be a relevant topic of discussion in the industry even today.
Role of Plant Breeding in Organic Agriculture
Critics of organic agriculture claim it's too low-yielding to be a viable alternative to standard agriculture. However, part of that poor performance may be the result of growing poorly adapted varieties. Breeding varieties specifically adapted to the unique conditions of organic agriculture is critical for this sector to understand its full potential.
This requires selection for traits such as:
Water use efficiency
Nutrient use efficiency (particularly nitrogen and phosphorus)
Weed competitiveness
Tolerance of mechanical weed control
Pest or disease resistance
Abiotic stress tolerance (i.e. drought, salinity, etc...)
Plant Breeding helps to enhance biodiversity. It has given the greatest benefit, by the usage of its products. Compared to any other techniques Plant Breeding is found to be simple where the process and the crop improvement ideas are simple.
FAQs on Plant Breeding: Techniques, Types, and Significance
1. What is plant breeding?
Plant breeding is the purposeful science and art of manipulating plant traits to develop new varieties with desired characteristics. It involves altering the genetic makeup of plants to improve their genotype and phenotype, aiming to enhance their value and utility for humans, particularly in agriculture.
2. What are the main objectives of a plant breeding program?
The primary objectives of plant breeding are aimed at improving crop varieties in several key areas. These include:
- Increased Crop Yield: Developing varieties that produce more grain, fruit, or fodder per unit area.
- Improved Quality: Enhancing nutritional value (e.g., protein content in wheat), flavour, or storage life.
- Biotic Stress Resistance: Creating varieties resistant to pathogens like fungi, bacteria, and viruses.
- Abiotic Stress Tolerance: Developing crops that can withstand environmental challenges such as drought, salinity, and extreme temperatures.
- Wider Adaptability: Breeding varieties that can be grown successfully across different environmental conditions and seasons.
3. What are the main steps involved in classical plant breeding?
A conventional or classical plant breeding program follows a systematic sequence of steps to create a new cultivar. The main steps as per the CBSE syllabus for the 2025-26 session are:
- Collection of Variability: Gathering and preserving all wild varieties, species, and relatives of the cultivated species. This is also known as germplasm collection.
- Evaluation and Selection of Parents: Identifying plants with desirable combinations of characters from the germplasm.
- Cross Hybridisation: Mating the two selected parent plants to bring the desired genes together in one progeny.
- Selection and Testing of Superior Recombinants: Identifying and selecting offspring from the hybrid population that have the desired combination of traits.
- Testing, Release, and Commercialisation: Evaluating the selected lines for yield and other traits in research fields, followed by testing in farmers' fields before releasing them as a new variety.
4. Why is the collection of genetic variability considered the most crucial step in any plant breeding program?
The collection of genetic variability, or germplasm collection, is the foundation of any successful breeding program. This is because variability is the raw material for selection. Without a diverse range of genes and alleles, a breeder has no options to choose from for creating new combinations. The entire potential of a breeding program to develop improved varieties for traits like disease resistance or higher yield is limited by the amount of genetic diversity available at the start.
5. What are the major methods used in plant breeding?
Plant breeders use several methods to improve crops. Conventional methods include introduction of new varieties, selection (like mass selection and pureline selection), and hybridisation to combine traits. More modern approaches include mutation breeding, where genetic variations are artificially induced, and polyploidy breeding, which involves changing the chromosome number. Advanced techniques like molecular marker-assisted breeding and genetic engineering are also used to make the process more precise and efficient.
6. What is the difference between pureline selection and mass selection?
Pureline selection and mass selection are two different methods for improving self-pollinated and cross-pollinated crops, respectively. In mass selection, a large number of plants with desirable phenotypes are selected, and their seeds are mixed to grow the next generation. In pureline selection, a single, superior plant from a self-pollinated crop is selected, and its progeny are grown and tested over several generations to develop a genetically uniform 'pure line'.
7. What is mutation breeding and how is it useful?
Mutation breeding is the process of inducing mutations in plants using chemicals or radiation (like gamma rays) to create new, useful traits that do not exist in the parent population. This technique is valuable because it can generate novel genetic variation when it is not available in the existing germplasm. For example, it has been used to develop disease resistance in crops, such as creating Mung bean varieties resistant to the yellow mosaic virus.
8. What is biofortification and can you give an example?
Biofortification is a key plant breeding objective focused on improving the nutritional quality of food crops. It involves breeding plants to have higher levels of essential vitamins, minerals, proteins, or healthier fats. The goal is to combat malnutrition in human populations. A prominent example is the development of Atlas 66, a wheat variety with significantly higher protein content, and Golden Rice, a variety of rice engineered to contain beta-carotene, a precursor to Vitamin A.
9. How was the Green Revolution in India dependent on developments in plant breeding?
The Green Revolution, which dramatically increased India's food production from the 1960s, was fundamentally driven by plant breeding innovations. Breeders developed semi-dwarf, high-yielding, and disease-resistant varieties of wheat and rice. For instance, wheat varieties like Sonalika and Kalyan Sona were developed by hybridising Mexican semi-dwarf wheat with Indian varieties. These new cultivars were highly responsive to fertilisers and irrigation, leading to a massive surge in crop yields and making India self-sufficient in food grains.
10. How can tissue culture techniques overcome challenges in conventional plant breeding?
Tissue culture offers solutions to several limitations of conventional breeding. For instance, somatic hybridisation allows the creation of hybrids between two species that cannot be crossed sexually. The technique of meristem culture can be used to generate virus-free plants from an infected parent. Furthermore, micropropagation allows for the rapid, large-scale cloning of a superior plant variety, a process much faster than traditional propagation methods.
