Subvarieties are different kinds of something that are part of a larger group or category.
Subvarieties are just smaller groups within a big group, like different kinds of fruit in the fruit group.
Examples:
There are many subvarieties of flowers, like roses and daisies.
In the store, there are many subvarieties of bread, like wheat and white bread.
He likes to study subvarieties of birds, like sparrows and robins.
The subvarieties of ice cream seem endless!
There are subvarieties of cars, like trucks and cars that are small.
The subvarieties of candy are his favorite thing to talk about.