300 SCIENCE PROGRESS 



unirrigated land the resulting grain contained 16*37 P^r cent of 

 protein, but in that raised on irrigated land the percentage fell 

 to 137 only. Howard has also found in India that over- 

 watering gives rise to mottled grain and to samples very uneven 

 in texture and therefore difficult to mill. In general long hot 

 days and absence of excessive moisture during the later weeks of 

 development increase the percentage of protein in the grain ; 

 where these conditions obtain wheat of high quality may always 

 be expected. 



The falling off in the percentage of protein in the piebald 

 wheat from the moist soils is merely the result of an increased 

 percentage of starch. It was long supposed that the protein 

 moved into the grain rather sooner than the starch did ; any 

 prolongation of grain formation would therefore be accompanied 

 by an excess of starch in the grain. This view explained very 

 well a number of facts like those recorded above, but the recent 

 investigations of Miss Brenchley and A. D. Hall threw grave 

 doubts on its correctness. They found that the material 

 transferred from the plant to the grain had much the same 

 composition, both in the earlier and the later stages of ripening. 

 The comparative poverty in starch of grain prematurely 

 ripened by dryness, rust, or any other cause would have to be 

 explained as the result of respiration continued after the filling- 

 in process was completed, respiration of course leading to loss 

 of starch but not of protein. 



The Economic Problem 



The object of the grower is simply to produce the wheat 

 giving the highest profit per acre whatever its intrinsic merits. 

 In England the "weak" wheats are most profitable in spite of 

 their lower price per bushel; "strong" wheats do not yield 

 sufficiently heavy crops to pay. In Canada, on the other hand, 

 " strong " wheats are the most profitable. Different varieties of 

 wheat behave differently under different conditions of climate 

 and soil, and perhaps the most pressing economic wheat 

 problem of to-day is to find the varieties most suitable to each 

 locality. Unfortunately nothing short of actual trial is sufficient, 

 and so we find long tedious trials carried out in various 

 countries to test the value of known varieties and to discover 

 promising new ones. In the past some very striking improve- 

 ments have been effected in this way. Square Heads' Master, 



