INTRODUCTORY 5 



India, Arabia, the Philippine Islands, Peru, Brazil, Venezuela, Salvador, 

 and other Central American Republics. 



Wheat has also a wide altitudinal range. In this country it is grown 

 from sea-level up to about 600 feet. 



Farther south, in the Swiss Alps and the Pyrenees, spring wheats 

 can be grown at an elevation of 4000 feet, and in the Tropics their cultiva- 

 tion is carried on at an elevation of 8000-10,000 feet in Mexico, Colombia, 

 Ecuador, and Abyssinia. 



Humboldt records its growth at an altitude of 14,000-15,000 feet in 

 Tibet. 



The greatest amount of the best wheats are produced in countries 

 where the winters are cold and the summers comparatively hot. So long 

 as the winter temperature does not fall below - 20 C. and the air and 

 soil are dry, the exposed plants suffer little, but at lower temperatures 

 the crop is damaged, and in some cases killed outright, unless protected 

 by a covering of snow. 



In regions of severe winters with cold winds and little snow only 

 spring wheats are grown, the autumn-sown winter wheats being reserved 

 for districts with a higher mean winter temperature, or where a sheltering 

 layer of snow is certain. 



For the most satisfactory growth and development of the grain a cool, 

 moist, growing season followed by a bright, dry, and warm ripening period 

 of 6-8 weeks, with a mean temperature of 18-19 C. (about 66 F.), is 

 necessary. 



In those parts of this country where the mean temperature of June, 

 July, and August is below 13-14 C. (56 or 57 F.) wheat is a hazardous 

 crop. 



In regard to the water-supply essential for the wheat crop, an annual 

 rainfall of 20-30 inches is sufficient, so long as the greater proportion of 

 it falls during the growing season. Some of the Macaroni and Club 

 wheats are capable of yielding remunerative returns in regions where the 

 rainfall is not more than 12-15 inches per annum, and there are records 

 of crops of Macaroni wheats grown in arid districts without any rainfall 

 between sowing and harvest, the necessary water being derived from the 

 rain stored in the soil from the previous season. 



Wheat is grown chiefly for its grain, which is ground and utilised in 

 the form of flour for the manufacture of bread and biscuits. 



Some varieties are employed in considerable amounts in the prepara- 

 tion of macaroni and similar pastes, and most of the " cracked," 

 " shredded," and " malted " " cereal foods " consist of specially treated 

 wheat. Occasionally the grains are cooked whole, and consumed with 

 milk, or used in soups in place ot pearl barley. 



Although the ^rain is useful food for farm animals, its production is 



