Question

Why do we find very little variations among sugarcane plants.?

Answer 1

because sugarcane is a plant which is propagated by grafting a method of vegetative propagation

Answer 2

Hello friend.

Sugercane use vagetative propagation for reproduction. Vegetative propagation is an asexual mode of reproduction and we know that in asexual mode of reproduction less variation takes place.
Hence, sugarcane plants have very little variations.
I hope this helps you.