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Seed ears should be selected in the field before husking, from nor- 
mal, vigorous plants that have produced sound, well-developed ears. 
Plants showing any evidence of disease, such as corn smut or the 
ear, stalk, and root rots, should be carefully avoided. The specific 
type of ear and plant is unimportant if selection is toward a kind 
that is adapted to the environment in which the crop is to be grown. 
The selection of unadapted types, such as large ears from late-ma- 
turing plants for conditions requiring smaller ears and earlier 
maturity, or plants that mature too quickly to utilize the full avail- 
able growing season, and the like, is the thing to be avoided. 
EAR-TO-ROW SELECTION 
Breeding corn by ear-to-row selection was introduced by the Illi- 
nois Agricultural Experiment Station aboirt 1896. It became popu- 
lar almost immediately and soon was in wide use. Ear-to-row selec- 
tion consists in planting the seed from each of a number of ears in 
individual rows and basing selection on the performance of these 
rows. That is, each row is harvested separately, the yield and 
quality of product is determined, and seed is selected from the better 
and more productive ear rows for continued selection and is multi- 
plied for general planting. 
Fundamentally, then, ear-to-row breeding is based upon the prin- 
ciple that the measured ability of the seed on a selected ear to pro- 
duce a crop of large size or specific character is evidence of the value 
of that ear for breeding stock. The exact method of applying this 
principle differs according to the means used (1) to overcome the 
influence of variation in the productivity of the soil on the indicated 
value of the different ears and (2) to obtain seed for continued selec- 
tion and for general planting. 
It was recognized that differences in the productivity of the soil 
from row to row frequently were more important in determining the 
yield of the various rows than were the inherent differences among 
the individual seed ears. Thus, a row from an ear that potentially 
was unproductive might yield well because of the soil in which this 
row grew. On the other hand, an ear row which should have yielded 
well might yield poorly because it occurred in an unproductive part 
of the plat. Two methods were used to overcome this effect of soil 
variation. A mixture of seed was planted in rows distributed at 
regular intervals among the rows of the ear-to-row plat. These 
check (or control) rows were harvested in the same way as the' ear 
rows, and their yields were used as a measure of the productiveness 
of the different parts of the plat. The other method of eliminating 
the effect of soil variation was to plant the seed from each ear in two 
or more rows in different parts of the plat instead of in one row. 
The average yield of two or more separate rows from the same ear 
is more likely to represent the true value of that ear for breeding 
stock than is a single row. The use of check rows, or replication, or 
both, became general in an effort to make the results of the ear-to-row 
plat a more reliable basis for selecting the productive ears. The 
length of row, number of replications, and frequency of check rows 
were details that differed with the individuals practicing this method 
of selection and need not be considered. 
