|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.