THE IMPORTANCE OF BROAD BREEDING IN CORN. 30 
In the early stages of corn breeding it was thought sufficient to 
select the largest and best-filled ears for seed. With the idea that 
like produces like, this was obviously the way to increase the size of 
the ear. It was soon found that some of the plants that produced 
large ears had undesirable characteristics and selection was moved 
from the crib to the field. 
The next stage was reached when it was realized that, though the 
ear was large and well filled and the plant had no objectionable fea- 
tures, some of the plants failed to reproduce their desirable character- 
istics In subsequent generations. ‘The finest plants are sometimes due 
to particularly favorable locations in the field rather than to inher- 
ent superiority. This led to the study of the behavior of the progeny 
of particular ears before deciding whether they were worthy of 
being used as the foundation of new varieties, and the so-called 
“ear to row.’ method of selection was developed. These more labori- 
ous methods of breeding have ail operated to limit the number of 
individuals tested and to restrict the crossing. 
The increased yields which follow an intelligent application of this 
method of selection when applied to an unimproved stock have caused 
two important factors to be largely overlooked: (1) The number of 
plants from which careful selection can be made by any one person 
is reduced from thousands to hundreds with a correspondingly re- 
duced chance of securing the individuals really superior as breeders; 
(2) these methods restrict the free crossing that 1s normal to the 
species, unless accompanied by the extremely laborious method of 
hand-pollination, which still further reduces opportunity of selection 
and renders the method inadequate, except where experiments are 
conducted on a very large scale, beyond the reach of the average 
farmer. 
It has long been known that seif-pollinated ears yield plants of 
greatly reduced vigor, and that a few generations of self-pollination 
usually result in sterility. Yet in spite of this obvious danger sign, 
nearly all of our corn breeders have continued to produce varieties 
with the narrowest possible foundation, often by using a single ear 
as the basis of the new variety and taking measures to prevent the 
bringing in of any new strains for fear of contamination. 
Had corn breeding developed independently the danger from nar- 
row breeding would doubtless have been more fully appreciated, but 
modern corn-breeding methods have been largely adapted from meth- 
ods that have proved successful with other crops, such as wheat, oats, 
and barley, in which self-pollination is the rule. With self-fertilized 
species it is as safe to start a variety from a single plant as it is 
to start a variety of apples from a single bud. Furthermore, these 
autogamous strains tend to show great varietal uniformity, and the 
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