Corn Investigations 
45 
Fig. 10. — Elemental strains of Hogue’s Yellow Dent corn after six years 
of inbreeding. The almost absolute uniformity of plants within 
each of the strains is suggested in the picture. Many such distinct 
strains form the foundation of an ordinary corn variety, in which 
they occur in hybrid combinations. 
several weeks, until all possible danger of chance fertilization 
of belated silks is past. The source of pollen is indicated with 
hardware black pencil, on the bag, which serves for temporary 
identification. As soon after pollination as is convenient, fully 
marked identification tags are tied to each ear. Rain is some- 
times a very disturbing element and may necessitate the renewal 
of bags over the tassels. Very satisfactory modifications of the 
above procedure are possible. 
LIFE OF POLLEN 
In controlled pollination it is desirable to know how long 
pollen will retain viability after being shed. It is necessary 
that any foreign pollen which may have lodged upon the tassel 
at the time of covering should have lost its viability before the 
pollen is used in fertilization. For the purpose of approximat- 
ing the life of pollen, the following tests were made: One hun- 
dred ear shoots of Hogue’s Yellow Dent corn were bagged to 
exclude pollen. A quantity of pollen was shaken into a bag 
from a large number of plants. This was immediately stored in 
a dry building of T5°-85° F. At intervals of 10,24,30,34,38,51, 
