158 THE TEMPERATURE OF THE SOIL [chap. v. 



in the water supply and the sequence of temperature 

 produce potent changes in the product. For example, 

 the wheats coming from regions possessing a " steppe " 

 climate, with rainfall in the growing season followed 

 by increasing desiccation and high temperatures, are 

 generally hard and translucent and possess a high 

 protein content. Typical examples are the Hungarian, 

 Manitoban and some of the southern Russian wheats. 

 On the other hand, wheats grown in climates possessing 

 a winter rainfall, even if followed by a completely dry 

 summer, are soft and mealy, possess a low protein 

 content and yield flour of much lower " strength " from 

 a baker's point of view. 



Climate is more potent than any other factor in 

 causing variations in the composition of wheat. Leclerc 

 and Leavett grew the same varieties of wheat in three 

 localities with widely differing climates, and in the next 

 year grew on seed from each locality at all three places, 

 with the following results as regards protein content : 



Thus the seed of Kansas origin containing 19-13 

 per cent, of protein, when grown in California in 

 1907 yielded grain only containing n-oo per cent, of 

 protein ; whereas in the same year seed from the same 

 original stock, but grown in California in 1906 and only 

 containing 10-38 per cent, protein, when moved back 

 to Kansas yielded grain containing 22-23 per cent, of 

 nitrogen. 



