8 
BULLETIN 1341, U. S. DEPABTMENT OF AGRICULTURE 
20-rowed ears, Nos. 1 and 3. The difference is not large, however, 
and the outstanding fact is the reduced yield of all the selected 
strains. 
Three of the fifteen crosses yielded more than C. I. Xo. 119, and 
a fourth, No. SX^^^o- 6, probably was more productive. The other 11 
crosses all yielded significantly less than C. I. No. 119. Only one 
cross, No. 3xNo. 1, yielded less than the better parent, and it yielded 
less than the poorer parent. There is a tendency for the crosses with 
a lower mean value for number of kernel rows to be more productive. 
These crosses also are between strains differing more with respect to 
number of rows. 
The mean values for number of kernel rows and for the relative 
productiveness of the crosses and their parent strains have been 
brought together in Table 3, where the crosses are arranged in the 
order of increasing differences between the number of kernel rows 
on the ears of the parent strains. These fall into three more or 
less natural groups, those in which the parents differed (1) by 
less than 4 rows, (2) by 4 to 8 rows, and (3) by 8 to 12 rows. The 
average productiveness of the crosses in these groups is 91.1, 96.7, 
and 100.2 per cent, respectively. 
Table 3. — Summary of data showing the relations 'between nuinders of kernel 
rows and productiveness in six selected strains of corn and of crosses between 
them 
Parent strains 
Average number of kernel rows on ears 
Relative productiveness as com- 
pared to C. I. No. 119 (per cent) 
Parent strains 
Cross 
Parent strains 
9 
[ 
c? 
Aver- 
age 
Differ- 
ence 
9 
c? 
Aver- 
age 
Cross 
No. 4... 
No. 1 
No. 3.. 
No. 2 
No. 3 
No. 3.. 
No. 2.._ 
No. l._ 
No. 3 
No. l.__ 
No. 1- 
No. 3._. 
No. 6 
No. 1 
No. 6 
No. 5 
No. 3 
No. 1 
No. 3... 
No. 2 
No. 4 
No. 1 
No. 2 
No. 5 
No. 4 
No. 5 
No. 6 
No. 3.. 
No. 6 
No. 1 
14.4 
22.0 
19.6 
16.2 
19.6 
19.6 
16.2 
22.0 
19.6 
22.0 
22.0 
19.6 
10.2 
22.0 
10.2 
13.1 
19.6 
22.0 
19.6 
16.2 
14.4 
22.0 
16.2 
13.1 
14.4 
13.1 
10.2 
19.6 
10.2 
22.0 
13.8 
20.8 
20.8 
17.9 
17.9 
17.0 
19.1 
19.1 
16.4 
18.2 
17.6 
14.9 
14.9 
16.1 
16.1 
1.3 
2.4 
2.4 
3.4 
3.4 
5.2 
5.8 
5.8 
6.5 
7.6 
8.9 
9.4 
9.4 
11.8 
11.8 
13.7 
21.4 
21.1 
17.7 
17.5 
16.6 
18.8 
19.8 
16.5 
17.2 
17.9 
14.9 
13.5 
16.7 
14.5 
91.6 
87.5 
85.7 
90.3 
85.7 
85.7 
90.3 
87.5 
85.7 
87.5 
87.5 
85.7 
88.3 
87.5 
88.3 
87.5 
85.7 
87.5 
85.7 
90.3 
91.6 
87.5 
90.3 
87.5 
91.6 
87.5 
88.3 
85.7 
88.3 
87.5 
89.6 
86.6 
86.6 
88.0 
88.0 
88.7 
88.9 
88.9 
86.6 
89.6 
87.5 
87.0 
87.0 
87.9 
87.9 
96.7 
90.6 
8.5.5 
92.2 
90.7 
91.9 
96.6 
95.2 
103.5 
96.3 
95.2 
99.7 
105.7 
96.0 
104.5 
The coefficient of correlation for productiveness of the crosses 
with the difference between the numbers of kernel rows in the two 
parent strains, as determined from the ungro'uped data, is 0.67±0.10. 
The correlation between the mean num.bers of rows of the crosses 
and their productiveness is — 0.78±0.07. Because of the way the 
strains were combined a large difference between the parents necessi- 
tates a lower average number of rows in the cross. There was no 
important relation between the number of rows and productiveness 
in the parent strains. Consequently it seems likety that the dif- 
ference between the parental numbers was the more important fac- 
tor influencing yield and that most of the relation indicated by 
