32 
BULLETIN 1489, U. S. DEPARTMENT OF AGRICULTURE 
plat. In both cases seed was selected only from detasseled plants 
of the selected rows and from the better available plants. 
In each of the 10 years beginning with 1913, seed from the high- 
yield plat, the low-yield plat, and the nonpedigreed strain was com- 
pared for productiveness. The average yield of each selection for 
the first and the second 5-year periods of the experiment and the dif- 
ferences between the selections are shown in Table 5. The data 
show clearly the failure of ear-to-row selection to increase the yield 
of corn above that which was obtained from mass-selected seed. The 
efficacy of ear-to-row selection in decreasing productiveness in these 
experiments is an interesting basis for speculation, but of little im- 
portance in the present connection. 
Table 5. — The average excess acre yield of the high-yield selection over the 
nonpedigreed^ strain and of the high-yield selection and the nonpedigreed strain 
over the low-yield selection of corn in Illinois 
[Adapted from Smith and Brunson (72, p. 572) ] 
Designation 
Excess of acre yield 
over— 
Nonpedi- 
greed 
strain 
Low-yield 
selection 
High-yield selection: 
1913-1917 
bushels . 
1.3 
1.5 
5.8 
1918-1922 
do...- 
15.2 
Nonpedigreed strain: 
1913-1917 
do... 
4.5 
1918-1922 
rio 
13.7 
Varieties that have been developed by ear-to-row selection have been 
included in many varietal comparisons and frequently have ranked 
at or near the top of the list. There are few if any varietal com- 
parisons which have continued over a series of years, however, in 
which A^arieties developed by ear-to-row selection have been signifi- 
cantly more productive than the better of the mass-selected varieties. 
This failure to produce outstanding varieties constitutes the best 
evidence of the fallacy of ear-to-row selection as a method of corn 
improvement. 
PLACE OF EAR-TO-KOW SELECTION 
It is probable that the yield of an entirely unselected or unadapted 
variety could be improved by one or two years of careful ear-to-row 
selection. It is questionable, however, whether the improvement 
would be enough more than that which could be had by mass selec- 
tion to warrant the extra trouble and expense of the more elaborate 
method. Certainly there is nothing in the experimental evidence to 
show that ear-to-row selection is worth while in a variety that already 
is well adapted. More rapid progress in altering such character- 
istics as height of ear, height of plant, chemical composition of the 
kernel, and the like probably can be made by ear-to-row selection 
than by mass selection. Such alterations, however, can be achieved 
so much more rapidly by selection within selfed lines that it is im- 
probable that ear-to-row selection has any real place in present- 
day corn improvement. 
