**3. Classification of germplasm**

Based on its need, germplasm has undergone an evolution over a certain period of years in response to particular requirement including


#### *Endangered Plants*

To a certain extent, these collections are artificial to a much extent because some of the classes or classifications are useful for more than one reason. Hence an active number of collections were previously breeder such as for formal breeding purposes. So, the following discussion is required to explain the classes of the collection which must serve.

#### **3.1 Base collection**

It presents the method of long-term preservation of genetic variability by storing in presence of optimum conditions. For base collection, the materials are not used for distribution except with the need for replacement of material that has been lost either from active or backup collection types. It includes the most explanatory sampling method being employed for checking out variability within the species group. They are most stable in the sense that they can store the variation which arises in the natural condition. But they are also dynamic in the sense that they have some novel collected materials, some collections being produced via plant breeding and population involving genetic materials are added as they are available. In this way, the storing for many decades can be possible so the loss of variability occurs during the processes of regeneration and storing present within the acceptable limits. It is the collection under a low level of humidity at the temperature of subfreezing which must be below −150 °C to 190 °C. But some difficulties are present, which include that they cannot bear the chilling or drying temperature. So, an alternative and long-term methodology are required which includes cryopreservation within the in-vitro cultures. A huge collection at a global level is initiated with a proper guidance and help of Food and agriculture organization by designing specific agencies which serve as the base as well as back up collections for principal species in case of principle crop plants. But most agencies also vary in their ability to fulfill all the responsibilities regarding its designation [13].

### **3.2 Back-up collection**

It supplements base collection at another location or another level. For example, laboratory at US national seed stores holds the collection of some of the duplicate backup samples of maize for the improvement of these crops. Similarly, the international research Centre of rice is abbreviated as IRR present in the Philippines for the collection of rice. So it holds collection as well as insurance for loss in primary CIMMYT and IRRI collections of crops [14].

#### **3.3 Active collection**

Active as well as base collection mostly includes the same type of materials. So, it provides the seeds and other raw materials for purpose of distribution as well as for other uses. So, it has been found that a certain collection of material is conserved for maintenance of sufficient collections of plants of each type in active collection particularly when it is required in a huge collection or amount. All the materials in this type of collection are maintained under a shorter half-life and in the response to more standards of variability. So, grow outs or techniques for replacing seed supplies in form of the active collection as compared to that available in the form of the base collection. Hence replacing the active collet ions being necessary at regular intervals is being necessary in the case of the base collection so puts the genetic association at the risk [15].
