Author: Vora Zarna N.
Ph.D. (Scholar), Department of Genetics and Plant Breeding,
Junagadh Agricultural University, Junagadh, Gujarat, India.
Correspondence email id: email@example.com
Looking to the adverse effects of chemicals (insecticides, pesticides, fungicides, weedicides, chemical fertilizers) on human health, animal health, soil health and environment, organic plant breeding is gaining increasing significance, the world over. Organic plant breeding refers to development of new cultivars without the use of any chemical.
Important points related to organic plant breeding are given below:
- Organic seed: The seed that has been multiplied under organic conditions at least for one generation is referred to as organic seed.
- Organic varieties: Those cultivars that originate from organic plant breeding techniques are known as organic varieties.
- In the organic breeding, chemicals are not used neither in the development of varieties nor in their testing.
- The entire evaluation of breeding material is carried out under organic conditions.
- Those breeding methods which do not use any chemical are used in developing organic varieties.
- In the organic plant breeding higher priority is given to quality of the product that yield.
- Organic varieties are produced under certified organic plant breeding programmes.
- Patenting of breeding material is not permitted because it will put restriction on free exchange of breeding material among breeders and farmers.
Breeding objectives :
- Competitiveness with weeds: it is considerable important for organic varieties where weedicides are not used. In non-organic breeding it is not so important because weeds can be suppressed through use of weedicides.
- Plant stature: Generally, varieties for organic use tend to be taller than those developed for non-organic production.
- In organic plant breeding higher priority is given to quality than productivity or yield.
- In organic plant breeding higher emphasis is given to maintain biodiversity in the variety.
- Higher degree of resistance to biotic stresses because insecticides/pesticides are not for controlling insects and diseases.
- Earliness so that a variety can fit well into multiple cropping system.
- Freedom from toxix substances.
- Resistance to lodging in cereals and sugarcane.
- Non shattering habit in legumes.
- Resistance to abiotic stresses such as, drought, soil salinity, metal toxicity, heat, frost, excessive moisture.
- Photo and thermo insensitivity.
- High photosynthetic and nutrition uptake efficiency.
- Wider adaptability and stability in production.
- Amenability to machine harvesting.
- Plant introduction: Any exotic variety developed without the use of any chemical. It can be released as a variety after through testing under organic conditions.
- Selection: It includes pure line selection, mass selection, progeny selection, clonal selection etc.
- Hybridization: It refers to combination breeding. It includes backcross, pedigree method, bulk breeding method and single seed descent.
- Biotechnology: The marker assisted selection can be permitted if GMOs and radiations are not involved in marker production. The meristem culture can be permitted particularly because of its key role in virus elimination.
- Population improvement approaches such as recurrent selection, biparental mating, diallel selective mating and disruptive mating can be used for developing superior inbred lines that can be utilized in hybridization programmes.
- The F1 hybrids are permitted provided the F1 offspring are fertile.
Advantages of organic plant breeding:
- It is used for developing cultivars and hybrids suitable for organic farming. The use of organic varieties helps in reducing the cost of cultivation by prohibiting use of various agrochemicals.
- Use of organic varieties is ecofriendly. It permits multiplication of natural enemies of harmful insects resulting in effective biological control.
- In organic plant breeding more emphasis is given on improvement of quality rather than yield.
- In organic plant breeding use of chemicals is prohibited. As a result there is no environmental pollution.
- Use of organic varieties will lead to sustainable agriculture. It will not deplete the resources.
- It promotes use of biological inputs such as organic manure, botanical pesticides which do not have any adverse effect on the ecosystem. Rather use of organic manures improves the physic-chemical properties of the soil.
Disadvantages of organic plant breeding:
- Induced mutations play important role in developing new varieties and creating extra variability for selection. Banning use of this technique will have adverse effect on progress of plant breeding.
- Protoplast fusion permits gene transfer between any two species related or unrelated. It has overcome the barriers of gene transfer between species and genera. Banning of this technique will act as a barrier in somatic hybridization.
- Genetically modified organisms are used to solve those problems that can not be resolved by conventional breeding methods. The ban on the use of GMO will have adverse effects in solving such problems.
- Tissue culture techniques such as embryo culture, ovary culture, anther culture etc. lead to extra variation which is used for selection of suitable material. Bann on these techniques will prolong development of organic varieties.
- The well known chemical colchicine is used for making interspecific hybrids fertile through chromosome doubling. Banning the use of colchicines will have adverse effects on interspecific hybridization.
- The CMS based hybrids without restorer genes are used in sugar-beets, cabbage and some forage crops. Bann on the use of this technique will adversely effect breeding of these crops.
- Banning above useful techniques/chemical will prolong the period of developing organic varieties.
- The breeding efficiency will go down and breeding will be more expensive.
- Restriction on the exchange of material between traditional and organic breeding will have adverse effects in the progress of breeding.
2. Molecular approach for plant breeding - by P. Singh
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