Answer:
The "international bank for rice" owns 90 thousands rice sample (hybrid) for researches:
There are 140 thousand types of rice in the world and the Int. bank for rice strains owns 90 thousands types (used only for researches and studies). However, the famous types, which are cultivated in most of the countries, are 19 types only.
The top 5 types of rice are: white rice, brown rice, yellow rice, and black rice.