Plant Breading And Its Advantages:

Plant breeding is the purposeful manipulation of plant species in order to create desired genotypes and phenotypes for specific purposes.

This manipulation involves either controlled pollination, genetic engineering, or both, followed by artificial selection of progeny.
Plant breeding often, but not always, leads to plant domestication.

Plant breeding has been practiced for thousands of years, since near the beginning of human civilization.
It is now practiced worldwide by government institutions and commercial enterprises.

International development agencies believe that breeding new crops is important for ensuring food security and developing practices through the development of crops suitable for their environment.

Types of Plant Breeding

Classical Plant Breeding:

uses deliberate interbreeding (crossing) of closely or distantly related individuals to produce new crop varieties or lines with desirable properties.
Plants are crossbred to introduce traits/genes from one variety or line into a new genetic background.
For example, a mildew-resistant pea may be crossed with a high-yielding but susceptible pea, the goal of the cross being to introduce mildew resistance without losing the high-yield characteristics.
Progeny from the cross would then be crossed with the high-yielding parent to ensure that the progeny were most like the high-yielding parent, (backcrossing).
The progeny from that cross would then be tested for yield and mildew resistance and high-yielding resistant plants would be further developed.
Plants may also be crossed with themselves to produce inbred varieties for breeding.

Modern Plant Breeding:

Modern plant breeding may use techniques of molecular biology to select, or in the case of genetic modification, to insert, desirable traits into plants. Application of biotechnology or molecular biology is also known as molecular breeding (see: Molecular breeding).

Modern facilities in molecular biology have converted classical plant breeding to molecular plant breeding Steps of plant.

The following are the major activities of plant breeding:
• Collection of variation
• Selection
• Evaluation
• Release
• Multiplication
• Distribution of the new
• Marker assisted selection

Sometimes many different genes can influence a desirable trait in plant breeding. The use of tools such as molecular markersor DNA fingerprinting can map thousands of genes. This allows plant breeders to screen large populations of plants for those that possess the trait of interest. The screening is based on the presence or absence of a certain gene as determined by laboratory procedures, rather than on the visual identification of the expressed trait in the plant.

Genetic modification of plants is achieved by adding a specific gene or genes to a plant, or by knocking down a gene with RNAi, to produce a desirable phenotype. The plants resulting from adding a gene are often referred to as transgenic plants. If for genetic modification genes of the species or of a crossable plant are used under control of their native promoter, then they are called cisgenic plants. Sometimes genetic modification can produce a plant with the desired trait or traits faster than classical breeding because the majority of the plant’s genome is not altered.

To genetically modify a plant, a genetic construct must be designed so that the gene to be added or removed will be expressed by the plant. To do this, a promoter to drive transcription and a termination sequence to stop transcription of the new gene, and the gene or genes of interest must be introduced to the plant. A marker for the selection of transformed plants is also included. In the laboratory, antibiotic resistance is a commonly used marker: Plants that have been successfully transformed will grow on media containing antibiotics; plants that have not been transformed will die. In some instances markers for selection are removed by backcrossing with the parent plant prior to commercial release.

The construct can be inserted in the plant genome by genetic recombination using the bacteria Agrobacterium tumefaciens or A. rhizogenes, or by direct methods like the gene gun or microinjection. Using plant viruses to insert genetic constructs into plants is also a possibility, but the technique is limited by the host range of the virus. For example, Cauliflower (CaMV) only infects cauliflower and related species. Another limitation of viral vectors is that the virus is not usually passed on the progeny, so every plant has to be inoculated.

The majority of commercially released transgenic plants are currently limited to plants that have introduced resistance to insect pests and herbicides. Insect resistance is achieved through incorporation of a gene from Bacillus thuringiensis (Bt) that encodes aprotein that is toxic to some insects. For example, the cotton bollworm, a common cotton pest, feeds on Bt cotton it will ingest the toxin and die. Herbicides usually work by binding to certain plant enzymes and inhibiting their action. The enzymes that the herbicide inhibits are known as the herbicides target site. Herbicide resistance can be engineered into crops by expressing a version of target site protein that is not inhibited by the herbicide. This is the method used to produce glyphosate resistant crop plants (SeeGlyphosate).

Main Advantages and Disadvantages of Selective Breeding

If you are running a farm, where in crops and livestock are your primary source of income, then it is highly important for you to find the best way to boost your efficiency. Take note that natural or organic farming does not always ensure best results, but there is one very good agricultural method for higher production—selective breeding.

Selective breeding is used to hereditarily encourage beneficial characteristics on both animals and plants. Basically, it is performed through controlled breeding. But like any other agricultural method (though they are supposedly designed to offer advantages for society), it also has its own set of disadvantages. If you are thinking of applying selective breeding into your crops and livestock, weigh them down to come up with a decision whether it is a great option for you.

1. It requires no company patent.

Any person who works in agriculture can start selective breeding whenever he wants. It is a way for him to naturally earn more income each year as he can breed specific characteristics into animals and plants to make them produce more over generations in the future, which is good for business. And since it is free, he just needs to be well-equipped and knowledgeable of the process to get the best outcome.

2. It allows for higher profit.

Selective breeding allows the encouragement of plant and animal characteristics that are more beneficial to farmers. For example, if they have selectively bred cows, these livestock can produce more milk than those typically bred, and the gene can be passed on to their offspring. When the method is used on crops, they will also grow more than the typical crops. Promoting these advantages is surely going to increase the market value of their products. For farmers who are in for a big business, selective breeding is definitely a perfect option for them.

3. It can create new varieties of good crops.

With this farming method, people will be able to produce higher amounts of crops. They can also produce plants with higher resistance to pests and diseases, not to mention the shorter period of time for harvest.

4. It does not have any issue of safety.

Unlike the process of creating genetically modified (GMO) crops, selective breeding allows for the natural evolutionary process to take place. It just happens at an accelerated rate as we manipulate it. However, the DNA sequences are not being tampered to create changes, such as genetic modifications.

5. It helps eliminate diseases.

One big advantage of selective breeding is its capability to eliminate animal and plant diseases. Studies revealed that identifying and pre-screening particular diseases allows farmers to control them. Thus, sooner or later, genetic diseases in plants and animals in the future will be eliminated.

6. It influences the production of food coming from plants in a positive way.

In plants, this agricultural method has the potential to positively influence the production of food around the world, in a way that it improves quality of seed grains and increase protein levels in forage crops. Selective breeding is also beneficial by giving plants the ability to grow on lands that are previously not suitable for farming. This means that farming businessman can get a variety of plants to grow and eventually more food.


7. It can provide a sustainable food chain.

With the projected world population to hit a mark of about 10 billion by 2050, it is more important than ever for world leaders to start planning a food chain system that would allow for the production of sufficient calories globally each year, so that people can be fed effectively, gradually eliminating hunger.

8. It allows for the creation of high-quality products.

Selective breeding has been a comfortable option on farming for many people, as it assures a process that will completely gave them superior types of products that are of high quality.

9. It can produce fitter and stronger animals.

the method of selective breeding can produce fitter and stronger animals that provide higher yields of meat, milk or eggs. For example, some cows have been bred to produce more meat. This should also be good as farmers can produce animals that are better suited to survive in marginal conditions or poor climates, preserving human food supplies and saving life. Moreover, this farming method can protect animals from developing diseases or deformities.

Refrences :

http://greengarageblog.org/16-main-advantages-and-disadvantages-of-selective-breeding
https://en.m.wikipedia.org/wiki/Plant_breeding
http://occupytheory.org/advantages-and-disadvantages-of-selective-breeding/