CONTINUOUS SELECTION FOR EAR TYPE IN CORN 7 
In order to determine whether any strain was grown on consist- 
ently better soil than the average, the yield of each plat was com- 
puted as a percentage of the average 3deld of the kind grown in that 
plat. A five-row moving average of these percentage yields then 
was computed, as described in a previous paper.* The means of the 
values so obtained for all of the plats of each strain or cross are 
shown in column 7 of Table 2. These values afford another measure 
of the reliability of the comparisons, as they indicate the relative 
productiveness of the soil on which the different lots were grown. 
Table 2. 
-Yields of grain of C. I. No. 119, of six strains of corn selected from it, 
and of ci'osses between these strains oMained in 1923 
strain or cross designation 
Total 
number 
of plants 
Shrink- 
age in 
drying 
Grain 
Average yield of air-dry 
shelled grain 
Mean 
of 5-row 
Per row 
Ratio to 
C.I. No. 119 
moving 
average 
1 
2 
8 
* 
5 
6 
7 
Section 1: 
C.I. No. 119 
No. 1 -- 
491 
329 
329 
328 
331 
329 
334 
333 
489 
330 
329 
332 
328 
335 
333 
330 
488 
331 
334 
331 
338 
338 
337 
339 
Per cent 
28.5 
33.1 
28.8 
29.8 
28.6 
25.4 
26.0 
25.7 
28.5 
28.7 
32.1 
29.7 
33.0 
31.0 
30.4 
29.9 
28.5 
33.6 
29.5 
27.5 
27.6 
26.8 
30.2 
26.8 
Per cent 
83.1 
83.2 
80.1 
83.6 
83.1 
82.0 
81.8 
82.5 
83.1 
83.6 
82.4 
82.9 
83.3 
83.8 
84.0 
83.2 
83.1 
79.0 
84.0 
83.3 
82.5 
81.5 
82.7 
82.5 
Pounds 
12. 3±0. 15 
10. 8± . 15 
10. 5± . 14 
11. 1± . 08 
11. 3± . 16 
10. 8± . 11 
10. 9± . 12 
11. 9± . 10 
12. 1± . 12 
11. 5± . 16 
10. 9± . 16 
11. 6± .19 
11. 5± . 15 
11. 6± . 12 
11. 7± . 15 
11. 1± . 16 
12. 0± . 14 
10. 2± . 14 
10. 9± . 13 
11. 0± . 10 
12. 4± . 13 
11. 9± . 15 
12. 5± . 12 
12. 6± . 12 
Per cent 
100. Od=0. 12 
87. 5± . 12 
85. 7± . 12 
90. 3± .06 
91. 6± . 13 
87. 5± . 09 
88. 3± . 10 
96. 7± . 08 
100. 0± . 10 
95. 2± . 13 
90. 6d= . 13 
96. 3± . 16 
95. 2± . 12 
96. 0± . 10 
96. 6± . 13 
92. 2± . 13 
100. 0± . 12 
85. 5± . 12 
90. 7± . 11 
91. 9± .08 
103. 5± . 11 
99. 7± . 12 
104. 5± . 10 
105. 7± . 10 
Per cent 
101 
100 
No. 3 
98 
No. 2 
99 
No. 4 
100 
No. 5 
99 
No. 6 
99 
No. 4XNo. 5 
101 
Section 2: 
C. I. No. 119 
No. IXNo. 2 .. . 
101 
99 
No. IXNo. 3 
98 
No. IXNo. 4 
100 
No. IXNo. 5 - - 
100 
No. IXNo. 6 
100 
No. 2XNo. 1 
100 
No. 2XNo. 3 
99 
Section 3: 
C. I. No. 119... 
No. 3XNo. 1 -. 
101 
100 
No. 3XNo. 2 
99 
No. 3XNo. 4 
100 
No. 3XNo. 5 
102 
No. 3XNo. 6 
99 
No. 6XNo. 1 
100 
No. 6XNo. 3... 
99 
DISCUSSION 
Without regard to the reason, it is evident that close selection to 
an}^ type, as practiced in these experiments, resulted in decreased 
productiveness. The most productive strain. No. 4, the 14-rowed 
smooth selection, yielded 8.4±0.20-per cent less than C. I. No. 119 
and the least productive, No. 3, the 20-rowed smooth selection, 
14.3 ±0.19 j)er cent less. The 14-rowed smooth and 16-rowed rough 
selections, Nos. 4 and 2, were more productive and also departed 
less from the characteristic condition of the parent variety than the 
otliers. If the difference in the productivity of the plats on which 
the strains were grown, as indicated by the data in Table 2 (column 
T), is taken into accoimt, the selections for 8-rowed and 12-rowed 
ears, Nos. 6 and 5, Avere more productive than the two selections for 
Richey, F. D. Op. cit. 
