What is Plant Breeding?
“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.
Let us have a detailed look at the objectives and steps involved in plant breeding.
Plant Breeding 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.
Types of Plant Breeding
There are the following different types of plant breeding:
In this, a plant with desired traits is crossed with a plant that does not have the desired traits but has several other traits.
In this, self-fertilization occurs. The progeny produced is the same generation after generation. This helps to preserve the original traits.
In this, two different breeds are crossed to produce the offspring that is more productive than the parents.
The mutations in plant genes result in new varieties. Mutations can also be induced in plants by exposing them to chemicals and radiation.
Genetic engineering helps in producing crops with desirable traits by inserting the gene of interest within the crop DNA. Such crops are known as genetically modified crops. E.g., Bt crops
Also Read: Plant Tissue Culture
Plant Breeding Steps
The plant breeding methods have undergone multiple amendments since it was started from 9000 – 11000 years ago. The modern method of plant breeding is carried out in the following steps:-
Collection of Variability
Variability forms the root of all breeding practices. The first step involves the collection of plants or seeds for all possible alleles for all genes in a given crop, which is known as germplasm. This collection even involves wild varieties and relatives of the cultivated species.
Evaluation and Selection of Parent Plants
The germplasm is evaluated for selection of parent plants with desired characteristics. The combination of these characteristics is expected in the hybrid progeny.
For example, a plant crop with high protein content can be selected to be crossed with a plant with higher disease resistance.
Cross-hybridization among Selected Parents
In the third step, the parents are cross-hybridized to develop pure lines of progenies. This is a tedious and time-consuming practice carried out in the conventional fashion of introducing pollen from one plant to the stigma of the other. Despite the labour involved, only one or two progenies in a few hundred show the desired combination of characteristics.
Selection and Testing of Superior Recombinants
The developed progenies are then evaluated and those with the desired combination of characteristics are self-pollinated to attain homozygosity.
Testing, Release and Commercialization of New Cultivars
The new lines are grown in research fields where they are tested for their agronomic traits of quality, yield, resistance to diseases, etc. This is followed by the cultivation of these crops in farmers fields at different locations in the country which represent the different agroclimatic zones. With successful results, the crops are released commercially for public consumption.
Also Read: Improvement of Crop Yield
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