40 MISCELLANEOUS PAPERS. 
the case in certain cotton hybrids, and if it should also prove to be 
an important factor in the increased yields of corn hybrids the 
results would warrant the production of hybrid seed in a breeding 
plot each year for field planting the following year. To secure 
hybrid seed it would only be necessary to plant two distinct varieties 
in alternate rows, detasseling one variety and using the seed from 
the detasseled variety for the next year’s general planting. Seed 
from the variety that was not detasseled would not be mixed and 
selections could be made to supply the breeding plot for the two 
following years. By detasseling the other variety in the next year a 
stock of pure seed of this also could be grown. By this system of 
alternation pure stocks of seed of the two varieties could be main- 
tained. There would be produced every year a stock of hybrid seed 
for the field planting of the next year and a stock of pure seed of one 
of the varieties for planting the seed plots of the two following years. 
The same result could be approximated by planting in the same 
way and detasseling one of the varieties in one half of the field and 
the other variety in the other half of the field. By this method 
seed of both the varieties would be secured each year, but there 
would be considerable indiscriminate crossing. 
The fact that corn is wind-pollinated makes the continual pro- 
duction of conjugate or first-generation hybrids on a commercial 
scale immensely more practicable with corn than with any other 
field crop. 
In still another way the artificial crossing of two varieties may be 
expected to increase the yield. With such hybrids none of the seed 
is self-pollinated, while with the crop grown in the usual way the 
percentage of self-fertilized grain must be very considerable. In 
most of our varieties the natural proterandrous tendency of corn has 
been reduced, until under ordinary climatic conditions the pollen of 
nearly every plant is still being shed when the silks become receptive. 
Unless the wind is blowing when the pollen is shed a large amount 
of self-pollination is inevitable. It is to be expected, therefore, that 
any method of treatment that would eliminate or reduce this self- 
pollination would result in an increase of the vigor and yield of the 
resulting corn plants, even without hybridization. The use of detas- 
seled plants for the production of seed may thus be found worth 
while, quite apart from the question whether detasseled plants them- 
selves yield more than those that are not detasseled. 
Whatever may be the true explanation of the increased fertility of 
hybrid corn plants, the fact remains that larger yields of corn can 
be secured in this way. The study of the methods by which these 
important factors can be made most effective should at least receive 
a place by the side of the study of elementary species and the quest 
of uniformity. 
al Ey 
