RELATION BETWEEN CERTAIN HERITABLE PROPERTIES 
OF WHEAT AND THEIR CAPACITY TO INCREASE PRO¬ 
TEIN CONTENT OF GRAIN 1 
W. F. Gericke, 
Laboratory of Plant Nutrition , University of California 
Table I gives the relation of two heritable characters of wheat 
with the percentage of increase in protein of the grain produced by 
an application of nitrogen supplied relatively late in the growth period 
of the plants. Explanation of the values ot the data is as follows: 
Column A gives the maximum per cent of gain in protein assumed 
to be due to application of nitrogen to the plant. The values were 
obtained by dividing the per cent protein in the grain of cultures that 
received nitrogen when 90 days old by that contained in the cultures 
which produced the lowest per cent of protein. The lowest values 
were obtained either from the cultures that did not receive nitrogen 
or those that received it at the time of planting. (That nitrogen 
supplied to wheat in pot cultures, or in the field at the time of plant¬ 
ing does, in some cases, result in a product lower in protein than 
would obtain if this material were not supplied, has been observed 
by some other investigators. As the explanation for this phenomenon 
would be aside the subject matter of this article, it will not be con¬ 
sidered in this paper.) 
Column B gives the per cent grain to total dry matter. These 
values represent differences considered as heritable among the vari¬ 
eties. (While the characters in columns B and C are considered by 
agronomists to be heritable and represent distinctions among vari¬ 
eties, it is known that the values of these characters may be changed 
by environmental conditions. Varieties showing marked differen¬ 
tiations, however, usually maintain appioximately their relative 
order for these characters even under diverse conditions. However, 
it is necessary, in a study of this kind, to appreciate that the relative 
values of any of the characters may change. 2 ) 
Column C represents the relative capacity of the varieties to ripen 
after nitrogen was applied, which factor may also be considered 
as genetic. The values were obtained by dividing the number of 
days required for ripening of plants which did not receive nitrogen 
by the number of days before ripening that nitrogen was applied to 
the cultures which produced the grain that had the highest per cent 
protein. # 
Column B differs from column A in that the order for Sonora and 
Fulcaster for third and fourth places, and for Hard Federation and 
Dart’s Imperial for fifth and sixth places, are interchanged. When 
columns A and C are compared, it is to be noted that the varieties 
for fifth and seventh places are interchanged. 
1 Received for publication Sept. 19, 1924; issued September, 1925. 
2 Gericke, W. F. some effects of physiological conditions on genetic characters of wheat 
Amer. Jour. Bot. 10: 275-277. 1923. 
Journal of Agricultural Research, 
Washington, D. C. 
( 67 ) 
Vol. XXXI, No. 1 
July 1,1925 
Key No. Calif.-40 
