68 
Journal of Agricultural Research 
Vol. XXXI, No. 1 
Table I. —Relation between two heritable properties of wheat varieties and their 
capacity to increase the protein content of grain 
A 
Capacity to increase in protein 
B 
Ratio of grain to total weight 
C 
Capacity to ripen after treatment 
Bunyip_ 
1.738 
Bunyip- 
.44.5 
Bunyip__ 
.3.00 
Cedar__ 
_1.635 
Cedar_ 
_40.5 
Cedar... 
.2.76 
Fulcaster_ 
_1.625 
Sonora___ 
_38.9 
Fulcaster_ 
_2.36 
Sonora_ 
.... 1.576 
Fulcaster__ 
_37. 7 
Sonora__ _ 
.2.29 
Dart’s Imperial _ 
— _ 1.559 
Hard Federation__ 
_35.1 
Early Baart__ 
_2.22 
Hard Federation_ 
_1.500 
Dart’s Imperial.. 
_32. 8 
Hard Federation. 
_2.21 
Early Baart_ 
1.498 
Early Baart_ 
_32.7 
Dart’s Imperial. 
_2.06 
White Australian_ 
_1.395 
White Australian_ 
.32.6 
White Australian_ 
_1.95 
Marquis a . .. 
.1.350 
Marquis... 
_30.2 
Marquis_ 
_1.88 
° For some reason, Marquis did not grow well. There was considerable mortality among the cultures. 
It is probable, therefore, that the order given it does not indicate its true value among these varieties. 
The way these varieties (which represent a range of very early to 
very late wheats) fall in order of correlation at once suggests causa¬ 
tive relations in some of their heritable properties and in the capacity 
of wheat varieties to produce high-protein grain. Owing to the fact 
that the protein content of grain can be increased by merely supply¬ 
ing nitrogen to the plants at certain phases of their growth, it follows 
that the genetic characters of varieties which are correlated to the 
capacity of the plants to increase the protein content of the grain 
must be agencies which influenced the physiological processes deter¬ 
mining the protein content of wheat. As this factor obviously bears 
on the relative rate of intake of nitrogen to that of other processes of 
growth, it follows that the effect of these genetic properties on the 
protein content of wheat must influence the rate of absorption and 
utilization of nitrogen by the plants. 
The ratio of grain to total dry matter is an expression of the rel¬ 
ative power of varieties to utilize absorbed material, including 
nitrogen, for grain production. However, as the per cent of protein 
in grain of any variety is determined by the amount of nitrogen those 
plants utilize for grain, and by the amount of grain produced, it 
follows that any change in this value must be due to changes in either 
or both factors. Whether wheat varieties which have the genetic 
property to produce nigh values of grain to total dry weight also 
possess correspondingly great capacity to produce high-protein grain 
when physiological conditions supervene which make this possible, 
has apparently not been determined. The fact of correlation be¬ 
tween these properties, as shown by the data, is evidence that varieties 
which have great efficiency for production of grain to total dry weight 
likewise have correspondingly great capacity to augment the protein 
content of the grain above the minimum for that variety. This, of 
course, does not mean that those varieties characterized by high 
percentage of grain to total dry weight invariably produce higher 
protein grain per se than do those varieties that do not have this genetic 
feature. The ratio of grain to total dry matter is only a measure of 
the capacity of the plants to increase the nitrogen in the grain and can 
not by itself determine what the absolute protein content of the 
grain will be. Furthermore, this property is also an expression of the 
degree of fluctuation to which the variety is subject. 
Whether or not high-protein grain will result from the capaqity 
of any variety of wheat to produce high percentage grain to tqtal 
