Corn Investigations 
9 
These methods differ primarily in the manner of continuing the 
high yielding ear-to-row strains as established in the initial ear- 
to-row tests. They are: (1) Continuous ear-to-row breeding: 
(2) increasing a single high yielding strain in isolation; (3) 
increasing a composite of several high yielding strains in isola- 
tion; and (4) crossing several high yielding strains. 
During a seven-year yield test, seed derived by these four 
practices yielded respectively 0.6 per cent less, 10.9 per cent less, 
2.6 per cent more, and 1.7 per cent more than the original corn. 
The great reduction in yield resulting from a single high yield- 
ing ear-to-row strain continuously grown in isolation is doubt- 
less due to close breeding. 
In a five-year test of ear-to-row strains with a different 
local variety, (1) continuous ear-to-row breeding resulted in 0.8 
per cent lower yield than the original, (2) increasing the eight 
best strains in composite under isolation yielded 4.7 per cent less 
than the original, and (3) crossing of ear-to-row strains yielded 
1.7 per cent more than the original corn. 
Improvement in yield of an adapted variety thru ear-to-row 
breeding seems rather uncertain, and 2.6 per cent increase is the 
maximum attained in these experiments. In the initial ear-to- 
row tests, the strains which were continued in these experiments 
had yielded approximately 20 per cent more than the original 
corn. 
9. As an average for eleven years, corn selected from an 
isolation seed plat in which the poorest half of the stalks were 
annually detasseled gave a grain yield 1.8 per cent greater than 
seed from a corresponding plat in which the best half of the 
stalks were kept detasseled. However, both yielded slightly less 
than the original, thus indicating that no actual improvement 
resulted from continuous detasseling of the stalks that appeared 
to be inferior. 
10. Three plants per hill in hills 42 inches apart is re- 
garded as the standard planting rate for corn in eastern Ne- 
braska and in a large part of the corn growing area elsewhere. 
Seed selected continuously from corn grown at this rate has 
yielded, during seven years, 0.6 per cent less than seed grown at 
the heavy planting rate of five plants per hill and 4.0 per cent 
more than seed grown continuously at the rate of one plant per 
hill. In all cases the best developed seed ears were selected from 
each seed plat, and compared for yield at a standard uniform 
planting rate. In a similar eight-year test with a different va- 
riety, the best ears selected from continuous planting rates of 
