TOPIC=Germplasm Activity - Conservation
Conservation refers to protection of genetic diversity of crop plants from genetic erosion. There are two important methods of germplasm conservation or preservation viz. 1) In situ conservation, and 2) Ex situ conservation. These are described below:
1) In - situ Conservation:
Conservation of germplasm under natural habitat is referred to as in situ conservation. It requires establishment of natural or biosphere reserved national parks or protection of endangered areas or species. In this method of conservation, the wild species and the complete natural or semi natural ecosystem are preserved together. This method of preservation has following main disadvantages.
1. Each protected are will cover only very small portion of total diversity of a crop species, hence several areas will have to be conserved for a single species.
2. The management of such areas also poses several problems.
3. This is a costly method of germplasm conservation.
2) Ex-Situ Conservation:
It refers to preservation of germplasm in gene bombs. This is the most practical method of germplasm conservation. This method has following three advantages:
1. It is possible to preserve entire genetic diversity of a crop species at one place.
2. Handling of germplasm is also easy.
3. This is a cheap method of germplasm conservation.
The germplasm is conserved either 1) In the form of seed. Or 2) In the form of meristem cultures. Preservation in the form of seed is most common and easy method. Seed conservation is relatively safe, requires minimum space (except coconut, etc) and easy to maintain .Glass, tin or plastic containers are used for preservation and storage of seeds. The seeds can be conserved under long term (50 to 100 years), medium term (10-15 years) and short term ( 3-5 years) storage condition. Roberts (1973) has classified seeds into two groups for storage purpose, viz. 1) orthodox and 2) Recalcitrant.
19 сен 2024
