The Evolution of Wheat - Goat Grass (2)

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As the cultivation of Cultivated Emmer spread into new areas, it reached the areas west and south-west of the Caspian Sea where the second diploid Goat Grass, Aegilops tauschii, occurs as a weed. This has a seed spike that readily fragments into separate barrel-shaped sections when ripe, each with a very hard 'hull'.

About 9,000 years ago, this Goat Grass, genome D, hybridised with Cultivated Emmer to form Spelt. Another similar hybridisation about 8,500 years ago created an early version of Bread Wheat. Both Spelt and Bread Wheat contain genes introduced from the hybridisation with this Goat Grass, including some controlling the amount of the gluten proteins gliadin and glutenin. When bread dough is kneaded, these two proteins create an elastic network that retains the carbon dioxide from the fermenting yeast and causes the dough to rise.