A Study of Colorado Wheat 
95 
says of this: ‘‘In other words the growth of the rust arrests development 
and induces premature ripening, which, as we have Sieen, means a straw 
in which still remains the elaborated food and a grain small, immature, 
rich in protein and deficient in starch.’’ 
Prof. H. Snyder, in Minnesota Station Bulletin No. 90, Abstract 
E. S. R., Vol. XVI, p. 1074 , gives the analyses of some rusted wheat- 
straws from which it appears that rust-free straw contains a little over 
one-half as much protein as badly rusted straw. The Abstract continues: 
“Wheat from rusted plants contained a higher percentage of protein, fiber 
and ash than some fully matured grain from rust-free plants grown under 
the same conditions. The percentage of carbohydrates was highest in the 
sound samples. Some of the rusted wheat samples contained as high as 
19.30 percent of protein.” These are the only references to the effects 
of rust Upon the composition of the plant and the grain produced that 
I have found. McAlpine, in his book “The Rusts of Australia”, p. 65, 
quotes the preceding statement of Shutt’s with approval, but adds 
nothing to it. 
Our Results Contrary To Prevailing Opinion 
The fact is that we have in 1914 and 1915 wheat which is very 
similar in composition but very different from wheat produced on the 
same ground in 1913, and so far I have not given any cause for the 
difference, but have stated that I believe it to be due to the severe at¬ 
tacks .of rust which prevailed during these years. It will be noted that 
the prevailing opinion is that wheat grown on affected plants is richer 
in protein than such as is matured on unaffected plants; it is also 
stated that shrunken wheat is higher in nitrogen than well-filled wheat. 
This may be correct, but it is certainly not the case with our wheat nor 
is the percentage of starch perceptibly affected, as is shown by the 
percentages of starch in the crops of 1913 and in 1915 grown without 
application of nitrates. The average percentage of starch in the 27 
samples of 1913 is 62.2, and for the same number of samples in 1915, 
grown under the same conditions of fertilization, the average is 61.5* 
There is a difference of only 0.7 of i percent in favor of the crop of 
higher quality. We must frankly admit that our results are contrary 
to the prevailing opinion on this subject. 
THE NITROGEN CONTENT 
In 1913 we studied the development of the nitrogen compounds in 
the plant from time of blooming till maturity. It is entirely sufficient 
for our present purposes to follow the course of the total nitrogen. 
This will be found in detail for the crop of 1913 on page 36 of Bulletin 
208. The percentages are given for the fresh plants, but the per¬ 
centages of dry matter are given on page 34. The variety used for these 
may be used to recognize the corresponding sample of grain given in 
