134 Plant Physiology 



They also mature early, ripening before the conditions are 

 such as to prevent development, and finally, they are able 

 to adjust themselves more or less to considerable changes 

 within the growing period. 



The following summary, adapted from Lyon, may 

 therefore indicate the conditions under which hard-wheat 

 production may be maintained : 



(1) A relatively dry atmosphere which emphasizes the 

 drought conditions. 



(2) A short growing period, which is equivalent to 

 early maturity and is unfavorable to starch-storage in the 

 later stages of growth. 



(3) A favorable nitrogen supply in available form. 



It may be readily inferred that if certain of these condi- 

 tions do not naturally obtain, or if they are artificially 

 changed, there may be a tendency to make softer wheats 

 of the hard varieties. From experiments in Washington 

 (Thatcher), it has been shown that the total precipitation 

 in the different counties of the state governs very closely 

 the composition of the kernel ; therefore, as under irriga- 

 tion, there is here a tendency with higher precipitation 

 to produce the characters of soft- wheat where otherwise 

 a hard-wheat would be developed. 



SUBSIDIARY WORK 



Students not taking work directly along agricultural lines may 

 be required to prepare a report upon some phase of the water 

 requirements directly related to drainage, some aspect of irriga- 

 tion, or the water-relations of special crops, utilizing any ac- 

 cessible literature. Agricultural students, less likely to consider 

 adequately the ecological aspects of vegetation, may be given a 



