(1) The following grains shall be fund-covered grains:
(a) Corn, wheat, soybeans, grain sorghums, rye, barley, oats, or popcorn; and (b) Other grains that may be approved for "fund-covered grain status" by a majority vote of the board.
(2) The board shall not approve for "fund-covered grain status" any grain that is not publicly traded on at least one (1) exchange in the United States or Canada.