Why are the Temperate Grasslands also called the ‘granaries of the world’?

Why are the Temperate Grasslands also called the ‘granaries of the world’?

The Temperate Grasslands are also called the ‘granaries of the world’ as in these regions wheat is cultivated and produced on a large scale with the help of mechanized tools and modern machinery. In these regions, large quantities of wheat are also exported.