50 ENVIRONMENT AND MILLING QUALITIES. 



have been considerably extended, and in the present paper an 

 account of the work done in the wheat growing seasons of 1909-10 

 and 1910-11 is to be found. 



The characters of the wheat grain which may be affected by 

 change of environment are the following : — 



1. Colour. While the general colour, red or white, of any 

 wheat remains the same no matter under what conditions it is grown 

 nevertheless the depth or tone of colour in red or white wheats is not 

 constant. In India, white wheats, when well grown under dry 

 farming conditions, are frequently much darker in tint than the 

 same wheat grown carelessly under a superabundant supply of canal 

 irrigation. Similar differences are to be seen in red wheats. 



2. Size and weight of grain. The size and absolute weight 

 of the grain vary very considerably both in different localities in the 

 same year and also in the same locality in different seasons. 



3. Composition. Much of the work on the effect of environment 

 on the characters of the wheat grain has been concerned with the 

 effect of change of environment on the nitrogen content of the grain — 

 the nitrogen content being taken not only as a measure of the per- 

 centage of gluten, but also as a rough indication of the strength of a 

 wheat. There are, however, exceptions to the general rule that the 

 higher the nitrogen, the greater the strength so that, in the present 

 state of knowledge, the only safe method of estimating strength is 

 by milling and baking tests. Quality as well as quantity of gluten is 

 important in this respect. For a flour to be really strong there must 

 be sufficient gluten of the right quality present. So far, while no ac- 

 curate relation has hitherto been found between chemical composition 

 and the bread-making value of wheat, nevertheless the trend of recent 

 investigations on this subject affords hope that the strength of 

 wheat may be explained from a chemical standpoint. Thus Wood 

 has found in the case of Fife and other strong wheats that the water 

 soluble phosphates in these flours is high — over 0*1 per cent, and 

 the chlorides and sulphates very low. They also contain more 

 magnesia than lime. Weak wheats on the other hand yield flours 



