CBSE Class 12-science Answered

There are two strategies involved in maintaining seed banks- ex situ and in situ. Ex situ approaches involve conserving samples of crop seeds under frozen storage conditions, where they may remain viable (able to germinate) for long periods of time.In situ approaches support and encourage the relationship between people and plants through which both natural and human selection pressures continue to result in the development of new crop varieties. The approach can be:

 

1. Sealed samples of individual accessions are placed in frozen storage.

2. When these samples begin to show decreased viability, they are regenerated. Regeneration involves removing the sample from the freezer, growing it at the conservation farm and replacing the previous frozen sample with newly produced fresh seed.

3. For each accession, duplicate samples are taken in order to have a back-up in case any individual regeneration attempt fails.