CORN, WHEAT, OATS, BARLF.Y, RYE 



63 



foundation to agricultural progress, and is now the foundation 

 for our great system of international commerce. 



The world's wheat crop. — Tlie world's yearly wheat crop 

 averaged 3,634,000,000 bushels for the period 1907-1916, 

 734,000,000 bushels, or 20.2 per cent of which was produced by 

 the United States during the same period. 



The percentage of the world's crops and to some extent the 

 world's distribution of wheat is given in the following tables : 



Percentage of World's Crop by Continents, 1914-1916 



Percentage of World's Crop of the Leading Countries, 1914-1916 



The average yield per acre varies from ten to thirty Imshcls. 

 Russia has the smallest yield per acre while Germany has the 

 highest. The United States has an average yield of a iittle over 

 fifteen bushels for the past live years. 



Within the United States the five leading wheat-producing 

 states are Kansas, North Dakota, Minnesota, Nebraska, and 

 South Dakota. These five states produce forty to forty-five per 

 cent of the entire wheat crop of the United States and nearly 

 ten per cent of the world's crop. The average ^deld per acre 

 within these states is ten and five-tenths to eighteen and five- 

 tenths bushels. North Dakota has the lowest average yield and 

 Nebraska has the highest. 



Origin of wheat. — The origin of wheat is unkno\\Ti, since its 

 cultivation precedes all history. De Candolle states: ''Very 



