The millets are a group of small-seeded species of cereal crops or grains, widely grown around the world for food and fodder. They do not form a taxonomic group, but rather a functional or agronomic one. Their essential similarities are that they are small-seeded grasses grown in difficult production environments such as those at risk of drought. They have been in cultivation in East Asia for the last 10,000 years Millets are major food sources in arid and semi-arid regions of the world, and feature in the traditional cuisine of many others. In Western India, Sorghum (called "Jowar" in Gujarati and Marathi, Jola in Kannada) has been commonly used with millet flour (called "Bajari" in Western India) for hundreds of years to make the local staple flat bread (called "Rotla" in Gujarati or "Bhakri" in Marathi or Rotti in Kannada). Millet porridge is a traditional food in both Russian and Chinese ?uisines. In Russia it is eaten sweet (with milk and sugar added at the end of cooking process) or savoury with meat or vegetable stews. In China it is eaten without milk or sugar, frequently with beans, sweet potato, and / or various types of squash. People with coeliac disease can replace certain gluten-containing cereals in their diets with millet. Millets are also used as bird and animal feed. Flour is a powder made of cereal grains or roots. It is the main ingredient of bread, which is a staple food for many civilizations, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history. Wheat flour is one of the most important foods in European and North American culture, and is the defining ingredient in most European styles of breads and pastries. Maize flour has been important in Mesoamerican cuisine since ancient times, and remains a staple in much of Latin American cuisine. Flour contains a high proportion of starches, which are complex carbohydrates also known as polysaccharides. Leavening agents are used with some flours, especially those with significant gluten content, to produce lighter and softer baked products by embedding small gas bubbles. The production of flour has also historically driven technological development, as attempts to make gristmills more productive and less labor-intensive led to the watermill and windmill, terms now applied more broadly to uses of water and wind power for purposes other than milling.