oct. 22,1917 Indirect Effects of Selections in Breeding Indian Corn 125 
of the selections on the four physical characters of ears mentioned 
above. 
Our data on the upper-ear plots cover four crops, 1908 to 1911. Our 
data on the lower-ear plots cover nine crops, 1908 to 1916, with the one 
exception of the single ears for 1911, owing to the fact that the records 
are not available for that case. 
DIFFERENCES IN MEANS 
[Table III and fig. 9 to 12] 
It is true in every case that the upper ears have a significantly larger 
mean value in length, weight, and circumference than have the corre¬ 
sponding lower ears of the same stalks. This fact stands out promi¬ 
nently in the graphic representations of figures 9 to 12. 
In mean length of ears these differences range from 5 to 30 per cent of 
the mean length of the shorter group of ears. 
In mean weight of ears the differences range from 14 to 70 per cent 
of the mean length of the lighter group of ears. 
In mean circumference of ears the differences range from a little less 
than 5 to 13 per cent of the mean circumference of the smaller group of 
ears. 
Table III. Type and variability of the two-ear strains of Indian corn 
upper-ear plot, crop of 1908 
Character and strain. 
Length of ear, in inches: 
Single ears. 
Upper ears. 
Lower ears. 
Circumference of ear, in 
inches: 
Single ears. 
Upper ears. 
Lower ears. 
Weight of ear, in ounces: 
Single ears. 
Upper ears. 
Lower ears. 
Rows of kernels on ear: 
Single ears. 
Upper ears. 
Lower ears.. 
Mean. 
Empir¬ 
ical 
mode. 
Standard devia¬ 
tion. 
Coefficient of varia¬ 
bility. 
. 7. 87o±o. 054 
■ 8- 739 ± -°52 
6. 840± . 072 
9.0 
8-5 
7 - S 
I. 750±0. 038 
. 956 ± . 037 
i- 344 ± .052 
22. 24±0. 51 
10. Q4± .42 
I 9 - 6 s± -77 
6. 067 ± . 020 
6. o6o± . 025 
5 - 479 ± -030 
6 .0 
5 * 75 
5 - 50 
.6301I: .014 
• 454± .018 
• 533 i • 021 
10.38* .24 
- 7 - 49 ± • 29 
9. 73± . 40 
8. 64 ± . 11 
8. 786 ± .098 
5* 69 ± . 13 
10. 0 
9.0 
6. 0 
2. 986± . 071 
1. 658 ± . 070 
2. 034^ .091 
34 - 57 ± -97 
18.88 ± .81 
35 - 75 ± r - 68 
18. 35 ± . 086 
18. 03 ± . 14 
18. 25 ± . 20 
18. 0 
18. 0 
18. 0 
2. 516 ± . 060 
2. 55 ± • 10 
2. 74 ± . 14 
I 3 . 7 i± -34 
14. ° 5 ± . 56 
IS- ° 4 ± -78 
