**4.1 Primary gene pool**

It is abbreviated as GP1 and it is the form of gene pool where the crossing of two species is much easier which ultimately leads to the production of sexually fertile organisms. It includes plants or other species which upon mating produce a very closely related species which is fertile via its reproductive means. In the gene pools, the genes can be exchanged in between the two reproductive lines via arranging simple crosses or hybridization patterns. So, it is also known as Gene pool one and is of prime importance in breeding lines.

### **4.2 Secondary gene pools**

This type of genetic material can lead to a partial type of fertility upon crossing with GP1 being referred to as the secondary gene pool. It can ultimately cross with the primary generic pool but the hybrids obtained after the process of hybridization usually produce offspring which are fertile to some extent which means that some of them are fertile while others are sterile. Transferring such genes to the primary form of the gene pool is a much difficult and laborious task and such type of genetic pool is also known as Gene pool two (GP2) [17].
