CERTAIN RELATIONS BETWEEN ROOT DEVELOPMENT AND 
TILLERING IN WHEAT: SIGNIFICANCE IN THE 
PRODUCTION OF HIGH-PROTEIN WHEAT 
W. F. Gericke 
(Received for publication December 7, 192 1) 
In two other papers/ the writer has shown how differences in the protein 
content and in the consequent quahty of a ''soft white" spring wheat 
(White AustraHan) are causally related to the nitrogen nutrition of the 
wheat plant. The conditions that made for the production of high-protein 
wheat in the investigation cited arose from appHcations of nitrogen at 
much later growth phases of the plant than that indicated by the seeding 
or early seedling stage. Abundant tillering and culm production were 
obtained from the cultures which received nitrogen late in the growing 
period, that is, from 48 to no days after planting. The cultures that 
received nitrogen at the time of planting tillered sparsely and produced 
fewer culms, usually only one per plant. 
That such marked differences in tillering could be obtained from equiva- 
lent applications of nitrogen per culture, applied, however, at different 
growth periods of the plant, suggested further study as to the causal con- 
ditions for these results. The cultures that produced the high-protein 
wheat also produced a much larger amount of total dry matter, this being 
partly accounted for by the abundant tillering. Obviously, this fact would 
suggest that the high-protein wheat cultures absorbed and utilized more 
nitrogen than the plants which produced the low-protein wheat, and this 
in view of the facts that all the cultures received the same amounts of 
nitrogen and that those that had the application of nitrogen during the 
longest period of time absorbed less than did those that had it for a much 
shorter period. 
That these differences in the amount of nitrogen absorbed by the 
plant may be accounted for by conditions arising out of differences in the 
extent of the root development of the cultures at the time nitrogen was 
supplied seemed to be a plausible explanation. It is generally known, and 
was also observed by the writer in the investigation cited, that the root 
development of wheat (and the same seems to hold for many other plants) 
is decidedly affected by the supply of nutrients in the soil in which the 
plants are rooted. The quantitative relation, however, of differences in the 
^ On the protein content of wheat. Science, n. ser. 52 : 446, 447. 1920. Certain rela- 
tions between the protein content of wheat and the length of the growing period of the 
head-bearing stalks. Soil Sci. 13: 135-138. 1922. 
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