Re: I wonder whether it is correct or not
Yes, it's fine.
'Type' and 'size' are different categories. Two things can be of the same size but of different types, or of the same type but of different sizes.
We don't know what 'type' means in this context, but we could guess that it refers to species.
Are you thinking that if two seeds are of the same species, then they must necessarily be the same size?