The correct answer to this open question is the following.
Although no map is attached, we can say that the "wheat bell" was the name given the Great Plains of the United States and Canada, where people are dedicated to cultivating wheat with a lot of success. The vast territory and its fertile soil encompass parts of Texas, Nebraska, Kansas, Oklahoma, North Dakota, South Dakota, Minnesota, Colorado, and Montana. In Canada, the production of wheat is very successful in Alberta, Manitoba, and Saskatchewan.