98 
CoivORADo Experiment Station 
age protein content of the 1914 crop for this variety of wheat was 5 
9.82 percent, against 13.63 in 1913. This is a very surprising result 
considering the advanced stage of development of the wheat at the 
time of the attack. My opinion at the time was that the crop was al¬ 
most safe against this kind of injury, but it evidently was not. Accord¬ 
ing to our observations of 1913 and 1915 this effect is very probable 
if the attack took place, as it must have done just at, or during the 
period of most active transfer. In 1915 the rust was very bad, I have 
no measure by which I can express the severity of the attack, but it is 
evident from the data given that it practically stopped the transfer of 
nitrogen to the heads, which is equivalent to saying the kernels- If 
it did this in 1915, we argue that it did the same in 1914, and that this 
is the cause of the low protein content of the grain. 
It may be true that the weather influenced the course of the de¬ 
velopment; it may also be true that the succession of crops may have 
been ill-advised, still, on 30 July, 1915, the nitrogen in the plants com¬ 
pared favorably in quantity in the stems and leaves with that present 
in 1913, and had the normal transfer taken place we should have had 
excellent wheat, for the plants were at this time large and thrifty, and 
the nitrogenous material already accumulated appeared ample to pro¬ 
duce wheat of good quality, but, as we have seen, this did not take place, 
and we had wheat with 8.41 percent of protein. The observations of 
Shutt and Snyder on the high proteid content of rusted wheat-straw 
are in harmony with this view. 
We have many samples of shrunken wheat in the crops of 1914 
and 1915, but these samples are not high in nitrogen, which we inter¬ 
pret as the natural result of the stoppage of the transfer of the nitro¬ 
gen. It seems that the movement of the carbohydrates is also interfered 
with and the shriveled wheat represents practically the condition of the 
kernel at the time of the attack. Some growth of the kernel takes place 
after the attack but it is so much less than would normally take place 
that it does not make the above statement wrong. 
Deposition of Nitrogen and Starch Takes Place Simultaneously 
This is not the view generally held, so far as I have been able to 
gather. The prevalent view is that the nitrogenous components of the 
kernel are the first and the carbohydrates the last to be laid down, so 
that shrunken kernels are considered to be caused by deficiency of car¬ 
bohydrates, chiefly starch. I have already called attention to the fact 
that the percentage of starch in the samples'of 1913 and 1915 are very 
nearly alike, though the weight of the kernels is very different, as the 
average weight per 1,000 kernels for the respective years may indicate 
in a general way. The weight per 1,000 kernels in 1913 averaged 38.35 
grams, in 1915 26.61 grams, a difference of 11.74 grams per 1,000 
