Plant breeding is the manipulation of plant species in order to create desired plant types that are better suited for cultivation, give better yields and are disease resistance.
Plant breeding is done to-
- Increase crop yield.
- Improve quality.
- Increase tolerance to environmental stresses.
- Make the plants resistant to pathogens.
- Increase tolerance to insect pest.
Steps in plant breeding technique
1. Collection of genetic variability or germplasm
- Collection and preservation of all the different wild species and relatives of the cultivated species.
- Evaluation of their characters.
- The entire collection having all the diverse alleles for all genes in a given crop is called germplasm collection.
2. Evaluation and selection of parents
- The germplasm is evaluated to identify plants with desirable combination of characters.
- The selected plants are multiplied and used in hybridization.
- Pure line is created wherever desirable and possible.
3. Cross hybridization among the selected parents
- Cross hybrisdisation of two selected parents by emasculation and bagging, to produce hybrids of combined character of both parents. For example- high protein quality of one parent may need to be combined with disease resistant from another parent.
- Usually one in few hundred to a thousand crosses offspring’s shows desirable combinations.
4. Selection and testing of superior recombinants
- Selection is done from the progeny of hybrids produced by cross hybridization.
- Hybrids plants that are superior to both of the parents are selected.
- Hybrids are self pollinated for several generations till they reach a state of homozygosity.
5. Testing, release and commercialization of new cultivars
- Selected pure lines are evaluated in the research field for their yield and other agronomic traits of quality, disease resistance etc.
- Testing is done in the fields of farmers at least for three generations.
- The material is compared with best available local crop cultivar.