U. S. DEPARTMENT OF AGRICULTURE 
MATERIAL AND METHODS 
A strain of Boone County White, Cereal Investigations (C. I.) 
Xo. 119, was used in the investigation. This previously had been 
selected for productiveness by the ear-to-row method for about 15 
years. Only sound well-formed ears were taken for seed during this 
time, but little effort was made to have the seed ears uniform as to 
particular characters. At the beginning of the present investiga- 
tion the ears of C. I. iSTo. 119 varied from smpoth with almost flinty 
kernels to very rough with pinched-dented kernels, but they were 
not as rough as in many^strains of Boone County White. 
ESTABLISHING THE STRAINS 
Selection of five strains was begun in 1915, a sixth strain being 
added in 1919. The basis of selection was as follows : 
Strain No. 1. — Rough ears, 8 inclies or more long, with 20 or more rows of 
pinched-dented kernels. 
Strain No. 2. — Rough ears, 8 inches or more long, with 16 rows of crease- 
dented to pinched-dented kernels. 
Strain No. 3. — Smooth ears, 10 inches or more long, 20 or more rows of 
dimple-dented to slightly crease-dented kernels. 
Strain No. 4- — Smooth ears, 10 inches or more long, with 14 rows of dimple- 
dented kernels. 
Strain No. 5. — Smooth ears, 10 inches or more long, with 12 rows of dimple- 
dented kernels. 
Strain No. 6. — Smooth ears, any length, with 8 rows of dimple-dented ker- 
nels. This strain originated from a few 8-rowed ears found among those in 
strains Nos. 4 and 5 in 1918. 
All the strains were grown in the vicinity of Washington, D. C, 
on essentially the same kind of soil. The mixed seed from 50 or 
more typical ears of a strain was planted in a field or plat. These 
plats were isolated as much as possible from each other and from 
other corn. Seed for the succeeding year was taken from only the 
interior rows when the plats were not completely isolated. 
During the period of selection, 1,000 ears of each strain were clas- 
sified on the basis of the number of kernel rows. These data are 
shown in connection with those from a similar classification of the 
ears from the yield comparison conducted in 1923. 
GROWING SEED FOR COMPARISON 
All of the seed planted in the 1923 experiments was growm in 
1922. Strains Nos. 2 and 4 were grown on private farms near 
Washington, and the other strains, including the original C. I. Xo. 
119, were grown in isolated plats at the Arlington Experiment 
Farm, Eosslyn, Va. Crosses were obtained by growing plants of 
the different strains in each of these plats and detasseling. All 
sound ears of the crosses were used in the experiment, without 
reference to the number of rows or indentation of their kernels. 
METHOD OF COMPARISON 
The productiveness of the different lots of seed was compared at 
the Arlington Experiment Farm in 1923. The soil was a uniformly 
productive silt loam that had been pumped onto a low area in 
dredging out the channel of the Potomac River. The corn was 
planted in hills 3.3 feet apart each way. Excess seeds were planted, 
and the plat was thinned to an almost perfect stand of two plants 
per hill when the seedlings were about 8 inches high. The climate 
