24 
BULLETIN 1164, U. S. DEPARTMENT OF AGRICULTURE. 
Table 6. — Frequency distributions for petal spot of the F 3 progenies of 1920 and of the 
parental and F. 2 populations of 1919 of the Holdon-Pima cotton hybrids. 
[The nature of the seed from which each Fs progeny was grown, the grade values of the F 2 parents, and the 
mean grades of the several populations are stated in columns 3, 4, and 5, respectively. In column 3 
the symbols S and Op indicate, respectively, seed from selfed or open pollinated flowers.] 
Num- 
ber of 
indi- 
viduals. 
Nature 
of the 
seed 
planted. 
Grade 
value 
of the 
F 3 
parent. 
Moan 
grade 
of F, 
prog- 
en v or 
other 
popu- 
lation. 
Frequency distributions (grades). 
Designation of the F? parent 
and the F 3 progeny. 

1 
2 
3 
4 
5 
6 
7 
8 
1 
2 
3 
S 4- On. 
4 
r> 
- 


No. 82 
9 




1 
2 
2 
2 
3 
3 
3 
3 
4 
4 
4 
4 
5 
5 
5 
6 


.2 
.4 

3.1 
1.0 
1.6 
2.0 

2.2 
2.5 
3.5 
1.9 
1.9 
3.1 
3.4 
2.8 
4.0 
4.9 
6.3 
6.6 
9 
12 
9 
12 
9 
3 
7 
16 
5 
10 
19 
7 
1 
4 
No. 172 
12 S 
No. 161 
10 
13 
9 
22 
10 
32 
16 
10 
37 
31 
23 
11 
13 
8 
Op. 
S - Op. 
S + Op. 
s 
s 
s 
s 
s 
s 
s 
s 
s 
s 
S 4- On. 
1 

No. 123 
1 
No. 19 
No. 61 
No. .102 
3 
4 
2 
2 
3 
3 
2 
1 
1 
2 
5 
2 
1 
No. 13 
4 
2 
1 
3 
1 
No. 178 
4 
No. 171 
No. 156 
2 
3 
7 
2 
2 
i 
2 
1 
1 
.... 
2 
4 
2 
.... 
"3* 
1 
1 
4 
7 
6 
1 
8 
No. 40 
No. 20 ; 
No. 9 
4 
1 
2 
2 
6 
"3' 
5 
5 
6 
1 
No. 140 

No. 16 
2 1 
8 1 
4 3 
4 
,. 2 . 
2 
3 
7 
No. 142 
No. 45 
No. 70 
21 i 
14 i S 
14 S 
1 
1 
2 
2 
1 
1 
3 
1 
B 
10 
2 
No. 134 
16 
18 
28 
s 
s 
s 
1 
1 
1 
No. 44 
4 
1 
No. 29 
3 
Holdon 
13 S 
13 S 

6.5 
2.5 
13 
Pima 
2 
28 
3 
15 
8 
F 2 
215 
s 
63 15 
25 30 3*8 
00 
/ 2 
.i 
<s* s- 
& 
T 
a s 
4 
&- 
■*o 
S? 
^ 
O 
\ 
ft 
1 
/=> // 
FIG. 35.— Boll index: Frequency distribution of 
Holdon X Pima F2 cotton plants, by grades, 
as used in computing the correlations. The 
ordinate figures indicate the number of plants 
as a percentage of the total population. 
^0 
JO 
A 
:> 
"5> 
<< 
^ 
J 
/ 
' 
X 
/ 
> 
\ 
-/■/' 
Fig. 36.— Bo'.I apex index: Frequency distribu- 
tion of Holdon X Pima F 2 cotton "plants, by 
grades, as used in computing the Correlations. 
The ordinate figures indicate the number of 
plants as a percentage of the total population. 
It will be seen from Table 6 that the four F 2 parents which had 
shown complete absence of the spot gave spotless F 3 progenies except 
that one individual each in progenies 161 and 123 showed presence of 
