Germplasm collection is necessary because

The correct options are
A Genetic variability is usually present in the wild relatives
B Wild relatives can be present in different geographical locations
C Desirable traits may be present in hundreds of different variants of a species
Plant breeding aims at bringing advantageous or useful traits in one crop or plant. The desirable traits are distributed in many variants of the plant and mostly found in the wild relatives of the plant species. The variants or the wild relatives may all be scattered in different geographical locations. So, collecting all variety of traits and pooling them to form a library is essential for a successful breeding program.