Niche crops

What crops are considered niche? If we rank by gross world production, i.e. corn (about 1 billion tons), rice and wheat (about 750 million tons), soybeans (350 million tons) and classify these crops as the main ones, and the rest, the production of which does not exceed 100 million tons, are classified as niche, then For a particular country, this approach is not entirely correct.

For example, for Ukraine sunflower is the main crop, but for some it is a niche crop, or maybe not cultivated at all in some countries. Or rice: world production of rice is approaching, like wheat, 800 million tons, and for Ukraine this is a niche crop. This question arose before writing the book “Niche Cultures”.