Wheats of the World
A selection of wheat species that are, or were, cultivated in different parts of the world are occasionally grown in the cereal cage. Four of the species are tetraploid wheats, the other six are hexaploid. Most are "free-threshing" but Vavilovi and Macha Wheats and Spelt retain the hard shell or 'hull' of the early wheat species and make the extraction of the grain a more difficult task.
View some details of the areas where these wheat species are grown
Bread Wheat (T. aestivum) is now the most widely cultivated wheat in the world, grown in most temperate regions. Over many years, newer varieties have been developed that have a greater yield than many of the older traditionally grown wheat species. This has led to a replacement by Bread Wheat in some parts of the world, with a subsequent loss of the older species from cultivation. This loss of species diversity may mean that some useful characteristics, such as fungal resistance or lodging resistance, could become unavailable to scientists creating new varieties. Seed banks held by the John Innes Centre at Norwich, custodian of the UK's cereal genetic resources, are therefore important for maintaining reserves of these traditional species for possible use in future wheat breeding programs.

Another tetraploid wheat, Durum Wheat (T. durum), is widely cultivated in areas with mild winters and hot summers. The ears are free-threshing with large, hard-textured grains that produce a coarse textured flour, known as semolina, when milled. After mixing with water to form a stiff dough, it can be extruded into various shapes before being dried to create a wide range of pasta products, such as macaroni, spaghetti and lasagne. When cooked, the starch absorbs water and softens but the high gluten content ensures that they retain their original shape without dissolving.

The remaining species were more commonly cultivated in the past although often restricted to limited areas, such as the Vavilovi Wheat of Armenia. A selection of these species are shown growing at the Mill in early July and the ripened plants in August. The seed spikes or 'ears' of all these species are displayed in a display case in the mill.