Question: Aojiru (青汁 ) is a Japanese vegetable drink most commonly made from kale or, which member of the grass family, is a major cereal grain grown in temperate climates globally?
Context: Aojiru (青汁 ) is a Japanese vegetable drink most commonly made from kale or young barley grass.  The drink is also known as green drink or green juice in English, a direct translation of the Japanese meaning.  Even though "青 " (ao) means "BLUE" in modern Japanese, it is still sometimes used to refer to green vegetation in older contexts. Korn (from German, "grain", "Brit. " "corn") also known as Kornbrand or Kornbranntwein (English: "grain brandy" or "grain spirit"), is a German colorless distilled beverage produced from fermented cereal grain seed.  In the production of "Korn" only the cereal grain types rye, wheat, barley, oat and buckwheat are permissible.  Most of the production is based on rye or wheat; barley and buckwheat are rarely used.  Barley is mainly used to obtain the required malt for the brewing process.  The addition of food color, flavorings, or sweeteners is not permitted.  Korn differs from vodka in that it is distilled to lower alcoholic proofs and less rigorously filtered, which leaves more of the cereal grain flavor in the finished spirit. Barley ("Hordeum vulgare" L.), a member of the grass family, is a major cereal grain grown in temperate climates globally.  It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago.  Barley has been used as animal fodder, as a source of fermentable material for beer and certain distilled beverages, and as a component of various health foods.  It is used in soups and stews, and in barley bread of various cultures.  Barley grains are commonly made into malt in a traditional and ancient method of preparation. The oat ("Avena sativa"), sometimes called the common oat, is a species of cereal grain grown for its seed, which is known by the same name (usually in the plural, unlike other cereals and pseudocereals).  While oats are suitable for human consumption as oatmeal and rolled oats, one of the most common uses is as livestock feed.  Oats are a nutrient-rich food associated with lower blood cholesterol when consumed regularly. Eleusine is a genus of Asian, African, and South American plants in the grass family, sometimes called by the common name goosegrass.  One species "(E. indica)", is a widespread weed in many places.  Another species "E. coracana", is finger millet, cultivated as a cereal grain in India and parts of Africa. Stover is the leaves and stalks of field crops, such as corn (maize), sorghum or soybean that are commonly left in a field after harvesting the grain.  It is similar to straw, the residue left after any cereal grain or grass has been harvested at maturity for its seed.  It can be directly grazed by cattle or dried for use as fodder.  Stover has attracted some attention as a potential fuel source, and as biomass for fermentation or as a feedstock for cellulosic ethanol production.  Stover from various crops can also be used in mushroom compost preparation. Wheat is produced in almost every state in the United States, and is the principal cereal grain grown in the country.  The type and quantity vary between regions.  The United States is ranked third in production volume of wheat, with almost 58 million tons produced in the 2012–2013 growing season, behind only China and India.  (But the combined production of all European Union nations is larger than that of China.)  The United States ranks first in crop export volume; almost 50% of its total wheat production is exported. Brachypodium distachyon, commonly called purple false brome or stiff brome, is a grass species native to southern Europe, northern Africa and southwestern Asia east to India.  It is related to the major cereal grain species wheat, barley, oats, maize, rice, rye, sorghum, and millet.  It has many qualities that make it an excellent model organism for functional genomics research in temperate grasses, cereals, and dedicated biofuel crops such as switchgrass.  These attributes include small genome (~270 Mbp) diploid accessions, a series of polyploid accessions, a small physical stature, self-fertility, a short lifecycle, simple growth requirements, and an efficient transformation system.  The genome of "Brachypodium distachyon" (diploid inbred line Bd21) has been sequenced and published in "Nature" in 2010. The Russian wheat aphid ("Diuraphis noxia") is an aphid that can cause significant losses in cereal crops.  The species was introduced to the United States in 1986 and is considered an invasive species there.  This aphid is pale green and up to 2 mm long.  Cornicles are very short, rounded, and appear to be lacking.  There is an appendage above the cauda giving the aphid the appearance of having two tails.  The saliva of this aphid is toxic to the plant and causes whitish striping on cereal leaves.  Feeding by this aphid will also cause the flag leaf to turn white and curl around the head causing incomplete head emergence.  Host plants: cereal grain crops including wheat and barley and to a lesser extent, wild grasses such as wheatgrasses, brome-grasses, ryegrasses and anything in the grass family. This is a list of barley-based drinks.  Barley is a member of the grass family, is a major cereal grain.  It was one of the first cultivated grains and is now grown widely.  Barley is used in various beverages and as a source of fermentable material for beer and certain distilled drinks.  In a 2007 ranking of cereal crops in the world, barley was fourth both in terms of quantity produced (136 million tons) and in area of cultivation (566,000 km2 ).
Answer: Barley