8 
BULLETIN 1157, U. S. DEPARTMENT OF AGRICULTURE. 
The data from the experiments at the Arlington Experiment Farm, 
Rosslyn, Va., from 1917 to 1920 are recorded in Table 4. The 
figures in the columns " Number of plants per hill" represent the 
actual number in each hill and not a calculated average. In 16 com- 
parisons the prolific outyielded the single-ear type 14 times and tied 
once. A comparison of the two types, based on the results obtained 
at the closest spacing in each experiment, shows that in 12 com- 
parisons the- single-ear type made the greater gain five times in yield 
per plant, eleven times in weight of ear, and once in the number of 
ears per plant. 
ANALYSIS OF THE YIELDS. 
A summary of the results of the nine experiments conducted at 
Clarksdale, San Antonio, and at the Arlington Experiment Farm 
shows that in a total of 41 comparisons of yield per plant the prolific 
exceeded the single-ear type 38 times, tied once, and was exceeded 
twice. In the number of ears per plant the prolific led in every 
comparison, whereas in the weight of ear the single-ear type led 
in every comparison. In a total of 32 comparisons the prolific 
exceeded the single-ear type 22 times in the relative gain in yield 
per plant, 26 times in the relative gain in number of ears per plant, 
and 7 times in the relative gain in the weight of ear. 
Three of the comparisons in which the single-ear type made rela- 
tively greater gains than the prolific in number of ears per plant 
and four of the comparisons in which it made relatively smaller 
gains than the prolific in the weight of ear occurred at San Antonio 
in 1919. In these experiments the single-ear type showed a marked 
tendency to produce more than one ear per plant and showed losses 
in the weight of ear as the spacing increased, producing its heaviest 
ear at the closest spacing. This was the only instance in the ex- 
periments that the single-ear type reacted in this manner. 
The average yield per plant, the weight of ear, and the number 
of ears per plant of the two types in the nine experiments are given 
in Table 5. 
Table 5. — Average yield per plant, weight of ear, and number of ears per plant in nine 
experiments at Clarksdale, Miss., San Antonio, Tex., and Rosslyn, Va. 
Type. 
Weight of dry ear 
corn (pound). 
Number 
of ears 
per plant. 
Yield 
per plant. 
Yield 
per ear. 
0.536 
.640 
0.514 
.388 
1.04 
Prolific . 
1.65 
These averages of the results of the nine experiments again indi- 
cate that an increase in the number of ears per plant has been more 
effective than an increase in the weight of ear in increasing the yield 
per plant. 
Considering the nine experiments as a unit, the yields of both 
types at each of the first four spacings are compared on a ratio basis 
in Table 6. The relative yields within each type at the different 
spacings are shown in the same table on a basis of 100 for the yields 
at the closest spacing. 
