73 Nebraska Agricultural Exp. Station , Research Bui. 20 
suits suggest that farmers in general would not increase their 
corn yields by exchanging seed with neighbors for the purpose 
of crossing with their own variety, except where seed selection 
has been so restricted that a measurable degree of close breed- 
ing has resulted. 
Table 29. — Summary showing comparison of F \ hybrids and 
their parents. Average for thirteen hybrids for four years , 
19U-1917. 
Average 
of 
female 
parent 
Average 
of 
male 
parent 
Average 
of 
both 
parents 
Average 
of 
hybrids 
Deviation of 
hybrids from 
Average 
of both 
parents 
Highest 
yielding 
parent 
(1) 
(2) 
(3) 
(4) 
(5) 
(6) 
(7) 
Date tasseling 
7/30 
8/1 
7/31 
8/1 
+ 1 
0.0 
Date ripe 
9/23 
9/23 
9/23 
9/24 
+ 1 
+ 1.0 
Days to maturity 
53.8 
53.0 
53.4 
53.9 
+0.5 
+0.9 
Stalk height, inches 
83.1 
88.0 
85.5 
86.8 
+ 1.3 I 
—1.2 
Ear height, inches 
41.0 
43.0 
42.0 
42.4 
+0.4 
—0.6 
Suckers per 100 plants. . . . 
10.0 
24.0 
17.0 
15.0 
2 
—9.0 
Lodged per 100 plants. . . . 
13.8 
15.0 
14.4 
15.4 
+ 1 
+0.4 
Ears per 100 plants 
82.5 
84.0 
83.2 
83.3 
+0.1 
—0.7 
Two-eared plants, per 100. 
3.0 
4.0 
3.5 
3.0 
■ — 0.5 
-1.0 
Shrinkage, per cent 
8.5 
10.2 
9.3 
9.7 
1 +0.3 
— 0.5 
Shelled corn, per cent .... 
83.0 
84.0 
83.5 
85.0 
+ 1.5 1 
+1.0 
Yield per acre, bushels. . . . 
40.5 
45.2 
42.8 
41.2 
—1.6 
—4.0 
FIRST, SECOND, AND THIRD GENERATIONS OF VARIETY HYBRIDS COMPARED 
The comparative yields of the first and second generations 
of the variety hybrids are given in Table 30 for a three- 
year period, 1915-1917. Comparative yields for the first, second, 
and third generation hybrids are also given for the two-year 
period 191G-1917. The second and third generation crops did 
not deviate on an average more than 1.5 bushels from the F, 
hybrid, with the slight difference in favor of the later genera- 
tions. Allowing this amount of difference for experimental 
error, we might conclude that the later generations of a variety 
cross tend to yield as well as the first generation. 
