30 The Colorado Experiment Station 
The two things are entirely distinct. We have flinty berries, wholly 
unobjectionable in any respect except that of having a blackened 
end, we also* have spotted or yellow-berries both witn and without 
such ends. The blackened ends are due to fungi; this fact is quite 
easily established by placing the black-ended berries in a culture 
dish under proper conditions when an abundant growth of the 
fungus affecting the berry will be obtained. Simple cases of yellow- 
berry do not afford this proof of fungous affection. 
The question of a “tendency” which is heritable is fully set 
aside by the fact that we can, iro-m the same lot of seed, under 
identical conditions of climate, grow crops affected with or free 
from yellow-berry. 
Furthermore, the question is not one of the total supply of 
plant food. I have given the yields per acre for two succeeding 
years for the same varieties of wheat planted on the same sections 
of ground, every fourth one of which is a check plot. The min¬ 
imum crop on any check plot for the two years is 31 bushels per 
acre, with the wheat weighing 63^ pounds per bushel. The same 
plot the succeeding year, without the application of any fertilizer 
and planted to the lowest yielding variety experimented with, 
yielded 43 bushels, weighing 63^ pounds per bushel. This yield 
and weight per bushel does not indicate any deficiency of fertility 
and yet this wheat is badly affected with yellow-berry. I deem it 
altogether justifiable to conclude that yellow-berry is not a matter 
of total available plant food in the soil. It is no more a matter of 
starvation than of fungous trouble, which has nothing whatever 
to do with it, nor of a total excessive supply, but evidently a ques¬ 
tion of the ratio in which these food elements', are present. In our 
case it is evidently the ratio between the potassium and nitrogen 
which determines the absence or presence of yellow-berry. I am 
satisfied that this is the cause of our yellow-berry and believe that 
the explanation is applicable to all cases. We have red wheats from 
some sections of Colorado which are white and mealy or starchy. 
These samples are as white and as mealy as any white wheat that I 
have seen. We have all degrees of this affection from a single, 
minute, yellow spot set in a flinty mass to the degree just desig¬ 
nated in which the whole kernel is mealy. The cause of this is the 
one just stated, the ratio of the available potassium to the available 
nitrogen. 
While it is possible that mealy wheat grown in Idaho or Cali¬ 
fornia might owe its mealiness or starchiness to some other cause, 
I hold it as quite certain that this is not the case, but that it is due 
to the fact that in these soils the ratio of available potassium to the 
available nitrogen is too high. There may be. as in our case 
